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Thread: What elements compose these substances?

  1. #1 What elements compose these substances? 
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    I'm sorry if my question sounds too basic, but I'm a "dummy" trying to understand chemistry. When I was in high-school, chemistry kind of put me off for one big reason: that it was difficult to apply in real life most of what I had learned. Atomic theory has been partly to blame. Of course it's easy to understand, but I found difficulty in relating all I learned with the objects I interacted with. For one part, I was not familiar with 95% of the elements I found on my periodic table. So it was hard for me to accept that all matter is comprised of all these unknown substances.

    But what's particularly always baffled me, even to this day, is that my intuition does not help me accept chemistry basics. As an example, when I drop a cup of glass and it breaks, what I see on the floor in tiny pieces is still glass again. For me, in my own stupid world, glass is basically an element. And so are many other substances which I come up with in my daily routine.

    I understand that if I had a microscope, maybe I would realize what these things are made of. Yet they never told me at school if glass was comprised of this and that element. I was just supposed to accept that these mysterious elements govern my world! And things got worse and worse when I had to take in that atoms "bond", or that they have X quantity of electrons in this or that shell, without even mentioning how we know these things. But that's another matter, probably more related with the educational system of modern times.


    Anyway, now I'm motivated to start all over, and for that I want to answer each and every one of my inquiries. And this is what I really need to know before I delve deeper into atomic theory:

    What are these common substances composed of, chemically?
    - Glass
    - Wood
    - Plastic
    - Paper
    - Leather
    - Clay
    - Wool
    - Ink
    - Glue
    - Soap
    - Meat


    I would really appreciate some help. I'm trying to teach myself chemistry but it's not easy for me.

    Thanks in advance!


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  3. #2  
    Universal Mind John Galt's Avatar
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    Most of the items you are listing are mixtures of often quite complex compounds.

    Glass: wikipedia states that "the most familiar type of glass is soda-lime glass, which is composed of about 75% silicon dioxide (SiO2), sodium oxide (Na2O) from soda ash, lime (CaO), and several minor additives." See more here.

    Wood is made up of a variety of organic polymers - long chains molecules where a basic "unit" is repeated many times over. Cellulose is the primary component. Google cellulose. You'll find it is made up of repetitive units of sugars.

    Plastics are also polymers, this time manufactured rather than natural. There are many varieties, again depending upon what the base unit is.

    Paper, typically, is made up of cellulose derived from wood.

    Leather - well it's animal skin and skin is again pretty complex. I think if you want to study chemistry you have to get away from such complex mixtures.

    Clay - complex molecular sheets of interlinked silica tetrahedra (one silicon surrounded by four oxygens) and aluminium octahedra (one alumiium surrounded by six oxygens) with elements such as potassium and calcium in the interlayer spaces.

    Etc.


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  4. #3  
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    I think that it is a shame the way chemistry has become a study of electrons and equilibrium calculations. I think that there is scope to have a chemistry course that seeks instead to familiarise people with the common chemicals in their environment. It could perhaps be called General Chemistry or something similar

    I'll make a start.

    Glass: Silicon, Oxygen, Sodium, Calcium, mainly.
    Wood: Carbon, Hydrogen, Oxygen, mainly
    Plastic: Carbon, Hydrogen, sometimes Chlorine(PVC), Fluorine (Teflon), Oxygen (PET bottles)
    Paper: Carbon, Hydrogen, Oxygen
    Leather: Carbon, Hydrogen, Oxygen, Nitrogen
    Clay: Silicon, Aluminium, Oxygen


    Is this the sort of thing you are after?
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  5. #4  
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    Quote Originally Posted by Matt24 View Post
    I'm sorry if my question sounds too basic, but I'm a "dummy" trying to understand chemistry. When I was in high-school, chemistry kind of put me off for one big reason: that it was difficult to apply in real life most of what I had learned. Atomic theory has been partly to blame. Of course it's easy to understand, but I found difficulty in relating all I learned with the objects I interacted with. For one part, I was not familiar with 95% of the elements I found on my periodic table. So it was hard for me to accept that all matter is comprised of all these unknown substances.

    But what's particularly always baffled me, even to this day, is that my intuition does not help me accept chemistry basics. As an example, when I drop a cup of glass and it breaks, what I see on the floor in tiny pieces is still glass again. For me, in my own stupid world, glass is basically an element. And so are many other substances which I come up with in my daily routine.

    I understand that if I had a microscope, maybe I would realize what these things are made of. Yet they never told me at school if glass was comprised of this and that element. I was just supposed to accept that these mysterious elements govern my world! And things got worse and worse when I had to take in that atoms "bond", or that they have X quantity of electrons in this or that shell, without even mentioning how we know these things. But that's another matter, probably more related with the educational system of modern times.


    Anyway, now I'm motivated to start all over, and for that I want to answer each and every one of my inquiries. And this is what I really need to know before I delve deeper into atomic theory:

    What are these common substances composed of, chemically?
    - Glass
    - Wood
    - Plastic
    - Paper
    - Leather
    - Clay
    - Wool
    - Ink
    - Glue
    - Soap
    - Meat


    I would really appreciate some help. I'm trying to teach myself chemistry but it's not easy for me.

    Thanks in advance!
    John G has given an indication of how your question can be answered. But I think if I were you I would start with simple, everyday examples of chemical change , rather than the composition of complex substances.

    For example, when you burn natural gas in a cold room, why do the windows steam up?

    Why does squeezing lemon juice onto cut apples prevent them turning brown?

    Why does water expand when it freezes?

    How does washing up detergent enable water to clean a greasy plate?

    Why is vinegar good for cleaning glass without leaving streaks?

    and so on.
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  6. #5  
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    It might help to group the things. The elements in bold are essential to, or at least very common in all members of the group.

    Plant origin: Wood, paper. Carbon, Hydrogen, Oxygen

    Animal origin: Leather, meat, wool Carbon, Hydrogen, Oxygen, Nitrogen

    Mineral origin: Glass , Clay. Silicon, Oxygen, Aluminium, Sodium, Calcium

    Oil origin: Plastic, some glues, inks. Carbon, Hydrogen , Oxygen, Chlorine, Fluorine, Nitrogen

    Combinations: Soap. Carbon, Hydrogen, Oxygen, Sodium, Potassium


    Oil is really a subset of vegetable.

    So the old description of animal, mineral or vegetable gives you an immediate insight into what is likely to be in there in terms of elements. And our world is dominated by just a handful of elements.
    Last edited by Warron; January 27th, 2014 at 07:02 AM.
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  7. #6  
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    Quote Originally Posted by Matt24 View Post
    For one part, I was not familiar with 95% of the elements I found on my periodic table.
    Most of them never occur naturally (or unnaturally) in their elemental form. And many of them are quite rare. So there is no reason you would be familiar with them. One of the joys of chemistry is learning about all those "unknown" elements. And the fact they all fit in the periodic table, means that there are patterns in the way the behave, etc.

    As an example, when I drop a cup of glass and it breaks, what I see on the floor in tiny pieces is still glass again. For me, in my own stupid world, glass is basically an element. And so are many other substances which I come up with in my daily routine.
    That's because doing something like breaking a glass is physics, not chemistry. The pieces are still glass. To change that you need (usually) higher energies and/or more extreme reactions to change atomic bonds, not just break the molecules apart.

    I understand that if I had a microscope, maybe I would realize what these things are made of.
    Even that wouldn't help.

    What are these common substances composed of, chemically?
    I wouldn't say this is a good place to start, because there are all complex materials. You should start with the basics. But anyway ...

    - Glass
    Silicon and oxygen, mainly. Other elements depending on the type of glass: lead, sodium, boron, uranium, ...

    - Wood
    - Plastic
    - Paper
    - Leather
    - Soap
    - Meat
    -Wool
    Carbon, hydrogen and oxygen. Mainly. Plus other trace elements (nitrogen, iron, phosphorous ...)

    - Clay
    Aluminium, silcon, oxygen, maybe other things in small quantities.

    - Ink
    Hydrogen, oxygen (because it is mainly water) and who-knows-what-else: iron? copper? nitrogen? carbon? (depending on the pigment/colour)

    - Glue
    Depends what sort of glue: but probably carbon, oxygen, hydrogen, nitrogen

    You'll see that the same common elements come up again and again in most materials (especially as manyof those are organic - i.e. from carbon-based living things)

    I would really appreciate some help. I'm trying to teach myself chemistry but it's not easy for me.
    Start from simple things like water (hydrogen and oxygen) ; common slat (sodium and chlorine) and reactions of common acids...

    Good luck. There are several chemists on the forum who may have good suggestions.
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    I should add that knowing what elements make up a substance doesn't really tell you much about the substance. For example, there are a very large number of different hydrocarbons, but they are all composed of carbon and hydrogen. What distinguishes one hydrocarbon from another is the way the carbon atoms and hydrogen atoms are bonded together, and even that is not enough to completely specify particular hydrocarbons, where relative location of the individual atoms in three-dimensional space becomes the only distinguishing feature between distinct hydrocarbons.
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  9. #8  
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    Good point.

    There are many examples like this: common table salt is sodium chloride. Sodium is a silvery and highly reactive metal. Chlorine is a greenish toxic gas. But salt is a transparent solid that dissolves harmlessly in water and is essential for life.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
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  10. #9  
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    Quote Originally Posted by KJW View Post
    relative location of the individual atoms in three-dimensional space becomes the only distinguishing feature between distinct hydrocarbons.
    A particularly spectacular example of this is hexahelicene:







    The mirror image of this hydrocarbon is a different hydrocarbon.
    There are no paradoxes in relativity, just people's misunderstandings of it.
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  11. #10  
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    Quote Originally Posted by exchemist View Post
    Quote Originally Posted by Matt24 View Post
    I'm sorry if my question sounds too basic, but I'm a "dummy" trying to understand chemistry. When I was in high-school, chemistry kind of put me off for one big reason: that it was difficult to apply in real life most of what I had learned. Atomic theory has been partly to blame. Of course it's easy to understand, but I found difficulty in relating all I learned with the objects I interacted with. For one part, I was not familiar with 95% of the elements I found on my periodic table. So it was hard for me to accept that all matter is comprised of all these unknown substances.

    But what's particularly always baffled me, even to this day, is that my intuition does not help me accept chemistry basics. As an example, when I drop a cup of glass and it breaks, what I see on the floor in tiny pieces is still glass again. For me, in my own stupid world, glass is basically an element. And so are many other substances which I come up with in my daily routine.

    I understand that if I had a microscope, maybe I would realize what these things are made of. Yet they never told me at school if glass was comprised of this and that element. I was just supposed to accept that these mysterious elements govern my world! And things got worse and worse when I had to take in that atoms "bond", or that they have X quantity of electrons in this or that shell, without even mentioning how we know these things. But that's another matter, probably more related with the educational system of modern times.


    Anyway, now I'm motivated to start all over, and for that I want to answer each and every one of my inquiries. And this is what I really need to know before I delve deeper into atomic theory:

    What are these common substances composed of, chemically?
    - Glass
    - Wood
    - Plastic
    - Paper
    - Leather
    - Clay
    - Wool
    - Ink
    - Glue
    - Soap
    - Meat


    I would really appreciate some help. I'm trying to teach myself chemistry but it's not easy for me.

    Thanks in advance!
    John G has given an indication of how your question can be answered. But I think if I were you I would start with simple, everyday examples of chemical change , rather than the composition of complex substances.

    For example, when you burn natural gas in a cold room, why do the windows steam up?

    Why does squeezing lemon juice onto cut apples prevent them turning brown?

    Why does water expand when it freezes?

    How does washing up detergent enable water to clean a greasy plate?

    Why is vinegar good for cleaning glass without leaving streaks?

    and so on.
    I should add one more thing. It is important in chemistry to apply the basic principle of the physical sciences that "systems" - of whatever sort - tend to find the lowest energy state they can, giving off energy to the environment in the process. That makes them more stable than the reactants were. So when you burn something, the products of combustion have lower energy than the reactants and the difference is the heat they give off in burning. Energy balances like this are crucial to understanding chemical change.
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  12. #11  
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    Quote Originally Posted by Strange View Post
    Good point.

    There are many examples like this: common table salt is sodium chloride. Sodium is a silvery and highly reactive metal. Chlorine is a greenish toxic gas. But salt is a transparent solid that dissolves harmlessly in water and is essential for life.
    Or consider carbon. Graphite, a form of pure carbon is so soft it is sometimes used as a lubricant, while diamond, pure carbon with a different structure, is the hardest naturally occuring substance.
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  13. #12  
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    Quote Originally Posted by John Galt View Post
    Or consider carbon. Graphite, a form of pure carbon is so soft it is sometimes used as a lubricant, while diamond, pure carbon with a different structure, is the hardest naturally occuring substance.
    With this example, one can look at it the other way and say that structure may be more significant than the chemical composition. For example, boron nitride is isoelectronic to carbon and also has two forms: a graphite form and a diamond form, and these two forms fairly closely match the physical properties of the graphite and diamond forms of carbon.
    There are no paradoxes in relativity, just people's misunderstandings of it.
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  14. #13  
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    And staying with the structural considerations, it is the folding, i.e. structure, of proteins that is primary consideration in their characteristics.
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    I think an understanding of the elements in common materials is an excellent place to start. It mirrors the historical development of chemistry itself. Some of the greats in the history of chemistry such as Scheele did their work prior to the understanding of chemical bonds or the complex structure of molecules.

    Scheele discovered many elements including oxygen, which proved to be pivotal in the history of chemistry.

    He also left us with one of the great lessons in chemistry: don't lick the spoon.
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    A simple understanding of some of the basic elements that make up our world can help us to understand some very important things such as the carbon cycle and the nitrogen cycle without consideration of molecular structure. Present a picture that is too complex at the outset and you will overwhelm and discourage. Perhaps that is why chemistry is so poorly understood in the general population.
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  17. #16  
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    Quote Originally Posted by John Galt View Post
    Most of the items you are listing are mixtures of often quite complex compounds.

    Glass: wikipedia states that "the most familiar type of glass is soda-lime glass, which is composed of about 75% sodium oxide from soda ash, (CaO), and several minor additives." See more here.

    Wood is made up of a variety of organic polymers - long chains molecules where a basic "unit" is repeated many times over. Cellulose is the primary component. Google cellulose. You'll find it is made up of repetitive units of sugars.

    Plastics are also polymers, this time manufactured rather than natural. There are many varieties, again depending upon what the base unit is.

    Paper, typically, is made up of cellulose derived from wood.

    Leather - well it's animal skin and skin is again pretty complex. I think if you want to study chemistry you have to get away from such complex mixtures.

    Clay - complex molecular sheets of interlinked silica tetrahedra (one silicon surrounded by four oxygens) and aluminium octahedra (one alumiium surrounded by six oxygens) with elements such as potassium and calcium in the interlayer spaces.

    Etc.
    Wow, thanks!! I didn't know all these substances were so complex. I had no idea so many different elements were a part of them.
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    Quote Originally Posted by Warron View Post
    It might help to group the things. The elements in bold are essential to, or at least very common in all members of the group.

    Plant origin: Wood, paper. Carbon, Hydrogen, Oxygen

    Animal origin: Leather, meat, wool Carbon, Hydrogen, Oxygen, Nitrogen

    Mineral origin: Glass , Clay. Silicon, Oxygen, Aluminium, Sodium, Calcium

    Oil origin: Plastic, some glues, inks. Carbon, Hydrogen , Oxygen, Chlorine, Fluorine, Nitrogen

    Combinations: Soap. Carbon, Hydrogen, Oxygen, Sodium, Potassium


    Oil is really a subset of vegetable.

    So the old description of animal, mineral or vegetable gives you an immediate insight into what is likely to be in there in terms of elements. And our world is dominated by just a handful of elements.

    Thank you so much!! This really helped me settle it all in my head.

    From all the replies I've read, it looks like the composition in itself is quite simple (made up of a handful of elements as you said) but that the difference between each substance is much more complex.

    Am I right?

    But thanks again for all the contributions. I'm thrilled that you guys are helping me so much!

    Quote Originally Posted by Warron
    I think an understanding of the elements in common materials is an excellent place to start. It mirrors the historical development of chemistry itself. Some of the greats in the history of chemistry such as Scheele did their work prior to the understanding of chemical bonds or the complex structure of molecules.

    Scheele discovered many elements including oxygen, which proved to be pivotal in the history of chemistry.

    He also left us with one of the great lessons in chemistry: don't lick the spoon.
    I'm glad to know that! I don't feel so stupid now (hahaha).

    The history of chemistry is exactly what I would like to see emphasized on school classes. Most of the time, it was all like: "Ok guys, this is a chain of atoms linked in a molecule. This atom has this many electrons etc etc." No one ever explained to me HOW we know that. Chemistry seemed to me to be a dogmatic subject (which is obviously not), rather than scientific.

    Unfortunately, I was too naive/young to ask all these questions. Now that I realize it I feel like I've lost an opportunity to learn interesting things. That's why I'm trying to start all over, this time teaching the subject myself.
    Last edited by Matt24; January 27th, 2014 at 08:35 PM.
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    Quote Originally Posted by exchemist View Post
    John G has given an indication of how your question can be answered. But I think if I were you I would start with simple, everyday examples of chemical change , rather than the composition of complex substances.

    For example, when you burn natural gas in a cold room, why do the windows steam up?

    Why does squeezing lemon juice onto cut apples prevent them turning brown?

    Why does water expand when it freezes?

    How does washing up detergent enable water to clean a greasy plate?

    Why is vinegar good for cleaning glass without leaving streaks?

    and so on.
    Hmm, those questions interest me so much, but I haven't the slightest idea how to answer them!

    The thing is, even if I knew the answers, they would still center around how certain molecules and atoms interact with the environment or with another object. But since I have no idea what lemon juice or an apple is made of, I don't fully comprehend chemical changes. Or at least I think I won't comprehend them.
    Last edited by Matt24; January 27th, 2014 at 08:20 PM.
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    Quote Originally Posted by Strange View Post

    Most of them never occur naturally (or unnaturally) in their elemental form. And many of them are quite rare. So there is no reason you would be familiar with them. One of the joys of chemistry is learning about all those "unknown" elements. And the fact they all fit in the periodic table, means that there are patterns in the way the behave, etc.
    Indeed, I've always been intrigued by all those elements, but my inability to understand how their structure influences their behavior (and the fact that I never came across them in real life) just means all information I can find is meaningless for me to get real knowledge.

    Even that wouldn't help.
    Really? Wouldn't it? I had heard that only in recent times chemists have been able to actually "see" atoms (something that was previously only theoretical). So I imagined that scientists took all the trouble in recent times to analyse each substance and see what they're comprised of. But I see that's a ridiculous thought now How do scientists find out about atoms then? I'm so confused.

    I wouldn't say this is a good place to start, because there are all complex materials. You should start with the basics. But anyway ...
    Where should I start then? Most chemistry introductory books and courses all start with atomic theory, and there are still so many things about atoms and elements that I still do not understand. How did you guys do to understand the subject (apart from intelligence and dedication, of course)?

    You'll see that the same common elements come up again and again in most materials (especially as manyof those are organic - i.e. from carbon-based living things)
    Yes, I can see now. It's amazing how carbon, hydrogen and oxygen are in almost every substance

    Start from simple things like water (hydrogen and oxygen) ; common slat (sodium and chlorine) and reactions of common acids... Good luck. There are several chemists on the forum who may have good suggestions.
    But don't I need to know more about atoms to understand reactions?


    Thanks for all the help anyway. I'm overwhelmed by all the help I've received in this forum!
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    You might like to follow the links in this post and comments.

    Without Chemistry Hacks, Life Itself Would Be …. – Greg Laden's Blog
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    Quote Originally Posted by Matt24 View Post
    Indeed, I've always been intrigued by all those elements, but my inability to understand how their structure influences their behavior (and the fact that I never came across them in real life) just means all information I can find is meaningless for me to get real knowledge.
    I'm sure your "inability" to understand only comes from a lack of knowledge. But the only way to solve that is to tack some sort of structured approach to learning. So, although understanding something about everyday "stuff" around us is good and will stimulate interest, I think you need to start from the basics. I'm sure there are some good online courses you could follow (try Coursera or the Open University, for example).

    Really? Wouldn't it? I had heard that only in recent times chemists have been able to actually "see" atoms (something that was previously only theoretical). So I imagined that scientists took all the trouble in recent times to analyse each substance and see what they're comprised of. But I see that's a ridiculous thought now How do scientists find out about atoms then? I'm so confused.
    Most of what we know about chemistry is from studying the way chemicals interact with one another. For example, if you dissolve metal in acid you get hydrogen gas and you get a new compound: the salt of the metal and the acid. This tells something about the nature of acids (hydrogen is important somehow) and metals (they form salts with acids) and so on. Similarly, if you burn hydrogen, you get water. That tells us something. Over hundreds of years, many such experiments were done, patterns found and properties of elements deduced (even when the element itself couldn't be isolated at the time).

    Being able to image atoms is useful for confirming some fine details (like how atoms are arranged on the surface of a material and how that affects it properties) but that is closer to physics than chemistry.

    Where should I start then? Most chemistry introductory books and courses all start with atomic theory, and there are still so many things about atoms and elements that I still do not understand. How did you guys do to understand the subject (apart from intelligence and dedication, of course)?
    In my case, years of reading books at home, going on to study chemistry at college and then reading a lot since.

    At the initial level, there is nothing terribly complicated; just some general patterns of behaviour, different ways atoms can bond together, etc. You need to learn something about the way the most common types of elements behave and then you can begin to predict other things.

    So, we already mentioned sodium (an "alkali metal") reacting with chlorine (a "halogen") to form common salt (sodium chloride). Other alkali metals (e.g. potassium) will do the same to produce similar salts (e.g. potassium chloride). Similarly, other halogens (e.g. iodine) will react with alkali metals to make similar salts (e.g. sodium iodide).

    You can learn a few basic facts like that about each group (column) in the periodic table and it might begin to make sense.

    But don't I need to know more about atoms to understand reactions?
    I don't think so (not initially). At least, not much. The key thing is the number of electrons -- that is what defines which element it is -- and how many of those are in the outermost "shell" -- that defines how it reacts with other elements.

    The electrons are arranged in layers (shells) around the atom. Normally, it is only the outermost shell that is responsible for the way an atom reacts. So, for example, sodium has 1 electron in its outer shell and chlorine has 7. There is a "magic" number of 8 (or zero) which is particularly stable or "desirable". So the sodium atom "lends" its one electron to chlorine so that they both now have more stable numbers of electrons -- as long as they stick together.

    Obviously, as with anything, it can get as complicated as you want (why in shells, why 8, etc.) But you don't need much more than "atoms want to fill (or empty) their outer shell" to understand a lot of the periodic table.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
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  23. #22  
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    Quote Originally Posted by Matt24 View Post
    Quote Originally Posted by exchemist View Post
    John G has given an indication of how your question can be answered. But I think if I were you I would start with simple, everyday examples of chemical change , rather than the composition of complex substances.

    For example, when you burn natural gas in a cold room, why do the windows steam up?

    Why does squeezing lemon juice onto cut apples prevent them turning brown?

    Why does water expand when it freezes?

    How does washing up detergent enable water to clean a greasy plate?

    Why is vinegar good for cleaning glass without leaving streaks?

    and so on.
    Hmm, those questions interest me so much, but I haven't the slightest idea how to answer them!

    The thing is, even if I knew the answers, they would still center around how certain molecules and atoms interact with the environment or with another object. But since I have no idea what lemon juice or an apple is made of, I don't fully comprehend chemical changes. Or at least I think I won't comprehend them.
    Well then why don't you find out? Get a book or just browse the web. There are plenty of places you can get answers to questions such as this, without getting tangled up in the structure of the atom and so on.

    I'll do the first one to give you an idea: CH4 + 2 O2 -> CO2 + 2 H2O + heat. One molecule of methane (CH4) reacts with 2 of oxygen (O2 because an oxygen molecule consists of 2 oxygen atoms) to produce one molecule of carbon dioxide (CO2) + 2 molecules of water. So you get a lot of water vapour when you burn natural gas. The heat energy released indicates the products are at a lower energy state (more stable) than the reactants. Which is why we say methane is inflammable (or nowadays "flammable", because people don't learn Latin any more).

    One tool every chemist finds invaluable (or very valuable, again for people who haven't learnt any Latin) is the Periodic Table of the elements. There is a good web-based one here: Dynamic Periodic Table

    No need to worry about all the funny names and symbols, but the first two or three rows contain most of the everyday elements you will come across.
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    There's a nice piece here on chemistry.

    Without Chemistry Hacks, Life Itself Would Be …. – Greg Laden's Blog

    There are also some nifty things like game cards and magnets here. Periodic Table of the Elements by WebElements
    "Courage is what it takes to stand up and speak; courage is also what it takes to sit down and listen." Winston Churchill
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    Quote Originally Posted by exchemist View Post
    or nowadays "flammable", because people don't learn Latin any more
    Ah the old recency illusion strikes again!
    flammable (adj.)
    1813, from Latin flammare "to set on fire"
    From: Online Etymology Dictionary

    So wrong on two counts.

    (Although inflammable (from Latin inflammare) is a few centuries older, so maybe you just have a very generous definition of "nowadays" )
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    Quote Originally Posted by Strange View Post
    Quote Originally Posted by exchemist View Post
    or nowadays "flammable", because people don't learn Latin any more
    Ah the old recency illusion strikes again!
    flammable (adj.)
    1813, from Latin flammare "to set on fire"
    From: Online Etymology Dictionary

    So wrong on two counts.

    (Although inflammable (from Latin inflammare) is a few centuries older, so maybe you just have a very generous definition of "nowadays" )
    Touché!

    My old OED says indeed that English "flammable" exists but is obsolete. Inflammable is said to come from Latin inflammabilis, and Old French enflammer, in both of which the in- or en- prefix denotes the setting on fire, as opposes to just burning. But you are right that flammare also seems to mean setting on fire, absence of the in- prefix notwithstanding.

    My reference to people not knowing Latin, however, was in relation to the perceived risk, nowadays, that some people might think the in- prefix in this context means NOT easy to set fire to. Which is why flammable has made a comeback on safety data sheets and in the safety industry generally, much to my disgust. Harrumph.
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    Quote Originally Posted by Strange View Post
    I'm sure your "inability" to understand only comes from a lack of knowledge. But the only way to solve that is to tack some sort of structured approach to learning. So, although understanding something about everyday "stuff" around us is good and will stimulate interest, I think you need to start from the basics. I'm sure there are some good online courses you could follow (try Coursera or the Open University, for example).
    In fact, I have signed up for a chemistry course on Coursera! Some topics are better explained than others though. It's nice for a start but I still feel like they are rushing through the concepts (for example, it went from a well-explained lecture on Energy basics to a lecture on "Force" without explaining its relation to Energy. For a dummy like me, that's a put-off. I'm still following the course anyway ). Maybe I should buy an introductory textbook? On Coursera they recommended "Introductory Chemistry Essentials" by Nivaldo Tro. Is that one worth it?

    Most of what we know about chemistry is from studying the way chemicals interact with one another. For example, if you dissolve metal in acid you get hydrogen gas and you get a new compound: the salt of the metal and the acid. This tells something about the nature of acids (hydrogen is important somehow) and metals (they form salts with acids) and so on. Similarly, if you burn hydrogen, you get water. That tells us something. Over hundreds of years, many such experiments were done, patterns found and properties of elements deduced (even when the element itself couldn't be isolated at the time).

    Being able to image atoms is useful for confirming some fine details (like how atoms are arranged on the surface of a material and how that affects it properties) but that is closer to physics than chemistry.
    That's exactly what I would like to know: how these patterns were found. In your example, you tell me that if you dissolve metal in acid you get hydrogen gas. But how do you know the product is hydrogen gas in the first place? It seems to me that each explanation depends on other pre-determined knowledge. Maybe I'm just overthinking it all, but I feel like I'm trying to understand geometry without knowing Euclid's premises. It's possible; however, you don't get the full picture.

    At the initial level, there is nothing terribly complicated; just some general patterns of behaviour, different ways atoms can bond together, etc. You need to learn something about the way the most common types of elements behave and then you can begin to predict other things.
    Yes, I didn't find chemistry terribly challenging in high-school. Actually I was sort of an A-student in the subject. Yet I feel like I got no real knowledge about real world chemistry. I can picture all the molecule bonding (remember all the long chains of hydrogen and carbon lol) but I've never been able to apply it though.

    Thanks again by the way!! I really appreciate your taking the time to help me sort out my issues with chemistry.
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    Quote Originally Posted by adelady View Post
    You might like to follow the links in this post and comments.

    Without Chemistry Hacks, Life Itself Would Be …. – Greg Laden's Blog
    Thanks! This was a nice video. Really showed how important chemistry can be even for everyday life. Will try one of those hacks when the chance comes!

    I also liked how it was both easy enough to understand, yet it contains more "complex" information about molecules, bonding, etc. Once I can feel confident about these topics (which I know are pretty basic, I admit) I'll re-watch the video again.
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    I suggest that you get hold of one of the old style chemistry texts. They take a different approach to how modern chemistry is taught. They usually introduce each element with a bit of historical context and explain some of the common compounds and reactions with examples of simple experiments. You might find that provides you with the level of information that you need. As I say, I think that chemistry has gone too far down the theoretical path for most people.
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    Quote Originally Posted by exchemist View Post
    Well then why don't you find out? Get a book or just browse the web. There are plenty of places you can get answers to questions such as this, without getting tangled up in the structure of the atom and so on.

    I'll do the first one to give you an idea: CH4 + 2 O2 -> CO2 + 2 H2O + heat. One molecule of methane (CH4) reacts with 2 of oxygen (O2 because an oxygen molecule consists of 2 oxygen atoms) to produce one molecule of carbon dioxide (CO2) + 2 molecules of water. So you get a lot of water vapour when you burn natural gas. The heat energy released indicates the products are at a lower energy state (more stable) than the reactants. Which is why we say methane is inflammable (or nowadays "flammable", because people don't learn Latin any more).

    One tool every chemist finds invaluable (or very valuable, again for people who haven't learnt any Latin) is the Periodic Table of the elements. There is a good web-based one here: Dynamic Periodic Table

    No need to worry about all the funny names and symbols, but the first two or three rows contain most of the everyday elements you will come across.
    Thanks, that was a good explanation! Really interesting and understandable.

    Thing is, most of the stuff I find is nowhere that simple. This is the first thing that came up when I googled lemon preventing the browning of an apple: "Most plants contain polyphenol oxidase, an enzyme stored in their cells that reacts to the oxygen in the air, a process called oxidation that causes apple flesh to turn brown. The acid in lemon juice interferes with this by stopping the reaction between the two substances. The process is believed to serve as a defense mechanism by discouraging animals and insects from further damaging the plants." In this case, I have no idea what an enzyme is or what polyphenol oxidase consists of, so it's much harder to understand (and it does not even mention what the lemon acid is made up of).

    Maybe I found your example easy just because I knew the composition of the objects in your example (even with ZERO knowledge of chemistry I know that water is H2O and methane is CH4)? I don't know.
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    Quote Originally Posted by Warron View Post
    I suggest that you get hold of one of the old style chemistry texts. They take a different approach to how modern chemistry is taught. They usually introduce each element with a bit of historical context and explain some of the common compounds and reactions with examples of simple experiments. You might find that provides you with the level of information that you need. As I say, I think that chemistry has gone too far down the theoretical path for most people.
    Hmm, thanks. Any special suggestion?

    I agree with you that it's gotten too complex theoretically. In my case, I don't think I had a bad teacher, but most of the students in the class (myself included) did not understand what they were studying (like when you're taught how to solve a math problem without knowing why what you are doing makes sense).
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    Quote Originally Posted by Matt24 View Post
    That's exactly what I would like to know: how these patterns were found. In your example, you tell me that if you dissolve metal in acid you get hydrogen gas. But how do you know the product is hydrogen gas in the first place? It seems to me that each explanation depends on other pre-determined knowledge. Maybe I'm just overthinking it all, but I feel like I'm trying to understand geometry without knowing Euclid's premises. It's possible; however, you don't get the full picture.
    That's a really good question!
    Maybe you should be studying history of science (I don't know if there are specific history of chemistry books/courses). That way you get to the bottom of how these things were worked out and get a background in basic chemistry as well.

    Of course, initially people didn't know this was hydrogen. Or even that it was the same gas. Then the properties were examined (lighter than air, flammable, produces water when burned) ... seems to be the same gas. Let's call it ... well, it generates water (hydro) so lets call it hydrogen.

    So, yes, it was a long slow process of puzzling it all out.
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    Quote Originally Posted by Warron View Post
    I suggest that you get hold of one of the old style chemistry texts. They take a different approach to how modern chemistry is taught. They usually introduce each element with a bit of historical context and explain some of the common compounds and reactions with examples of simple experiments. You might find that provides you with the level of information that you need.
    There are couple of modern books like that as well, for the lay reader. For example:
    Nature's Building Blocks: An A-Z Guide to the Elements: John Emsley: 9780199605637: Amazon.com: Books
    Periodic Tales: A Cultural History of the Elements, from Arsenic to Zinc: Hugh Aldersey-Williams: 9780061824739: Amazon.com: Books
    A Guide to the Elements: Albert Stwertka: 9780199832521: Amazon.com: Books

    I have only read the first of those. It is interesting and even, occasionally, a useful reference.
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    Quote Originally Posted by Strange View Post
    Quote Originally Posted by Warron View Post
    I suggest that you get hold of one of the old style chemistry texts. They take a different approach to how modern chemistry is taught. They usually introduce each element with a bit of historical context and explain some of the common compounds and reactions with examples of simple experiments. You might find that provides you with the level of information that you need.
    There are couple of modern books like that as well, for the lay reader. For example:
    Nature's Building Blocks: An A-Z Guide to the Elements: John Emsley: 9780199605637: Amazon.com: Books
    Periodic Tales: A Cultural History of the Elements, from Arsenic to Zinc: Hugh Aldersey-Williams: 9780061824739: Amazon.com: Books
    A Guide to the Elements: Albert Stwertka: 9780199832521: Amazon.com: Books

    I have only read the first of those. It is interesting and even, occasionally, a useful reference.
    You've just beaten me to it! I was going to recommend "Periodic Tales" as well. There's a review of it here:-

    Periodic Tales by Hugh Aldersey-Williams: review - Telegraph
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    Quote Originally Posted by Strange View Post
    Maybe you should be studying history of science (I don't know if there are specific history of chemistry books/courses). That way you get to the bottom of how these things were worked out and get a background in basic chemistry as well.

    Of course, initially people didn't know this was hydrogen. Or even that it was the same gas. Then the properties were examined (lighter than air, flammable, produces water when burned) ... seems to be the same gas. Let's call it ... well, it generates water (hydro) so lets call it hydrogen.

    So, yes, it was a long slow process of puzzling it all out.
    I reckon that the witches of old weren't adding things like "eye of newt" to their cauldrons, but were adding things like "butter of antimony", "oil of vitriol", "sugar of lead"... they were just misheard.
    There are no paradoxes in relativity, just people's misunderstandings of it.
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    Quote Originally Posted by KJW View Post
    Quote Originally Posted by Strange View Post
    Maybe you should be studying history of science (I don't know if there are specific history of chemistry books/courses). That way you get to the bottom of how these things were worked out and get a background in basic chemistry as well.

    Of course, initially people didn't know this was hydrogen. Or even that it was the same gas. Then the properties were examined (lighter than air, flammable, produces water when burned) ... seems to be the same gas. Let's call it ... well, it generates water (hydro) so lets call it hydrogen.

    So, yes, it was a long slow process of puzzling it all out.
    I reckon that the witches of old weren't adding things like "eye of newt" to their cauldrons, but were adding things like "butter of antimony", "oil of vitriol", "sugar of lead"... they were just misheard.
    There is actually a good book called "The Last Sorcerer" about Newton, which points out the murky interface at the dawn of modern science, between real scientific thought and alchemy, biblical numerology and kindred quasi-scientific practices. We all think of Newton as a rock of modern rationality but it was not so simple.

    And, as for "sugar of lead", I have read that the composer G F Handel at a couple of points lost the use of his hands (catastrophic for an organist) due to the practice of sweetening rough wine of the period with lead salts. Safe! He had to go and take the waters at Aix or somewhere for the nerves to recover. It was a rough old world in those days, when chemistry was so poorly understood.
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    Quote Originally Posted by Matt24 View Post
    Quote Originally Posted by exchemist View Post
    Well then why don't you find out? Get a book or just browse the web. There are plenty of places you can get answers to questions such as this, without getting tangled up in the structure of the atom and so on.

    I'll do the first one to give you an idea: CH4 + 2 O2 -> CO2 + 2 H2O + heat. One molecule of methane (CH4) reacts with 2 of oxygen (O2 because an oxygen molecule consists of 2 oxygen atoms) to produce one molecule of carbon dioxide (CO2) + 2 molecules of water. So you get a lot of water vapour when you burn natural gas. The heat energy released indicates the products are at a lower energy state (more stable) than the reactants. Which is why we say methane is inflammable (or nowadays "flammable", because people don't learn Latin any more).

    One tool every chemist finds invaluable (or very valuable, again for people who haven't learnt any Latin) is the Periodic Table of the elements. There is a good web-based one here: Dynamic Periodic Table

    No need to worry about all the funny names and symbols, but the first two or three rows contain most of the everyday elements you will come across.
    Thanks, that was a good explanation! Really interesting and understandable.

    Thing is, most of the stuff I find is nowhere that simple. This is the first thing that came up when I googled lemon preventing the browning of an apple: "Most plants contain polyphenol oxidase, an enzyme stored in their cells that reacts to the oxygen in the air, a process called oxidation that causes apple flesh to turn brown. The acid in lemon juice interferes with this by stopping the reaction between the two substances. The process is believed to serve as a defense mechanism by discouraging animals and insects from further damaging the plants." In this case, I have no idea what an enzyme is or what polyphenol oxidase consists of, so it's much harder to understand (and it does not even mention what the lemon acid is made up of).

    Maybe I found your example easy just because I knew the composition of the objects in your example (even with ZERO knowledge of chemistry I know that water is H2O and methane is CH4)? I don't know.
    Well I knew when I wrote it that the apple browning one would be the most tricky. I was a bit vague about it myself. But this explanation seems fairly clear: Why Cut Apples Pears Bananas and Potatoes Turn Brown

    Interestingly, some cookery sites say (wrongly, it appears) that it is "ascorbic acid" (aka vitamin C) in lemon juice that prevents the browning. Whereas this explanation says it is just that acid - of any sort - denatures the enzyme in apples that causes the process. The main acid in lemon juice is of course citric acid (French citron = lemon). Vitamin C is present too, but at a far lower concentration.

    So we seem to have our first example of popularly believed chemical ballocks - the exposure of which is a pastime I enjoy, slightly more than is strictly healthy.
    Last edited by exchemist; January 29th, 2014 at 06:12 AM. Reason: missing word
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    Quote Originally Posted by exchemist View Post
    It was a rough old world in those days, when chemistry was so poorly understood.
    Yes, but it was probably a lot more exciting, with a lot more freedom, without worrying about OH&S or the DEA.
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    Quote Originally Posted by Matt24 View Post
    Quote Originally Posted by Warron View Post
    I suggest that you get hold of one of the old style chemistry texts. They take a different approach to how modern chemistry is taught. They usually introduce each element with a bit of historical context and explain some of the common compounds and reactions with examples of simple experiments. You might find that provides you with the level of information that you need. As I say, I think that chemistry has gone too far down the theoretical path for most people.
    Hmm, thanks. Any special suggestion?

    I agree with you that it's gotten too complex theoretically. In my case, I don't think I had a bad teacher, but most of the students in the class (myself included) did not understand what they were studying (like when you're taught how to solve a math problem without knowing why what you are doing makes sense).
    I think that Partington's Textbook of Inorganic Chemistry is excellent. I began with that at age 11 and am on my second copy, having worn the first one out.
    Another excellent one is Lowry and Cavell Intermediate Chemistry (1954)
    Another is Smiths Inorganic Chemistry by Kendall (1928)

    There are many more. These have all been out of print for a long time so you can only pick them up second-hand. Most second-hand book shops of reasonable size will have something that might be suitable.

    When I was a kid, we all had chemistry sets and mucked around with chemicals in the back shed. And you could buy quite a range of chemicals and equipment from chemical supply shops. Sadly, the proliferation of backyard drug labs as well as ever increasing safety regulations means that you can't do that now.

    When I finished high school in 1969, history of chemistry was still part of the first level course. It was during the 60s that the whole approach to teaching chemistry changed. The same applies to maths actually.
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    Quote Originally Posted by Strange View Post
    That's a really good question!
    Maybe you should be studying history of science (I don't know if there are specific history of chemistry books/courses). That way you get to the bottom of how these things were worked out and get a background in basic chemistry as well.

    Of course, initially people didn't know this was hydrogen. Or even that it was the same gas. Then the properties were examined (lighter than air, flammable, produces water when burned) ... seems to be the same gas. Let's call it ... well, it generates water (hydro) so lets call it hydrogen.

    So, yes, it was a long slow process of puzzling it all out.
    Yes, think I need to know about those processes to content myself. I understand why it would be pointless to teach it in school (as they probably consist of long stories of experiments and hypotheses), yet it would help inquisitive natures like me who want to know about everything.

    Indeed, probably the names of the elements can tell a lot about their function and behavior. I don't know Latin, but I know "phosphorus" is related to light (as in other languages like Spanish, matches are called "fósforos" - don't know why English didn't pick up that Latin root).

    Maybe studying Latin would be a smart move? Kind of reminds me when one of my teachers explained to me where the names of the months came from. It was an eye-opener! That's when I realized the usefulness of Greek and Latin as base languages. However, I always found them too complex to even try to learn them.

    Quote Originally Posted by Strange View Post
    These books sound so interesting!! I should check them out. Yet they sound a bit encyclopaedic. Maybe I'm wrong. But if they go from A to Z then I will read first about Aluminium (which is comparatively recent if I'm not mistaken) and only about Gold, Oxygen later (which have a greater history of research and were discovered before aluminium).

    Does one of these start from 0 knowledge? They all sound compelling though, but I haven't enough time to add that many more books on my "to-read" list.

    Thanks for your help!
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    Quote Originally Posted by exchemist View Post
    Well I knew when I wrote it that the apple browning one would be the most tricky. I was a bit vague about it myself. But this explanation seems fairly clear: Why Cut Apples Pears Bananas and Potatoes Turn Brown

    Interestingly, some cookery sites say (wrongly, it appears) that it is "ascorbic acid" (aka vitamin C) in lemon juice that prevents the browning. Whereas this explanation says it is just that acid - of any sort - denatures the enzyme in apples that causes the process. The main acid in lemon juice is of course citric acid (French citron = lemon). Vitamin C is present too, but at a far lower concentration.

    So we seem to have our first example of popularly believed chemical ballocks - the exposure of which is a pastime I enjoy, slightly more than is strictly healthy.
    Thanks, that was a better explanation. It's still clearer when you put it as a simple chemical molecule formula, as you did with the natural gas problem (CH4; 2O2 -> CO2 2H2O; can't get simpler than that).

    Unfortunately, those pseudoscientific articles are probably the fault of those of us with no chemistry knowledge. I would've fallen in for it as a coherent explanation! What is more, I thought that it only happened with apples (as they had iron). I never noticed it with bananas, pears or potatoes! Guess I either eat them too fast (hahahaha) or don't eat them much (don't remember the last time I ate pears, not my fruit to be honest). It's interesting that they all share a common characteristic.

    So, bottomline: maybe I just need to google better to find the simple explanations I need.
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    Quote Originally Posted by Warron View Post
    I think that Partington's Textbook of Inorganic Chemistry is excellent. I began with that at age 11 and am on my second copy, having worn the first one out.
    Another excellent one is Lowry and Cavell Intermediate Chemistry (1954)
    Another is Smiths Inorganic Chemistry by Kendall (1928)

    There are many more. These have all been out of print for a long time so you can only pick them up second-hand. Most second-hand book shops of reasonable size will have something that might be suitable.

    When I was a kid, we all had chemistry sets and mucked around with chemicals in the back shed. And you could buy quite a range of chemicals and equipment from chemical supply shops. Sadly, the proliferation of backyard drug labs as well as ever increasing safety regulations means that you can't do that now.

    When I finished high school in 1969, history of chemistry was still part of the first level course. It was during the 60s that the whole approach to teaching chemistry changed. The same applies to maths actually.
    Wow, it was good luck that you were in school at that time before the approach was changed. I only wish that could've happened to me! But I guess most people today would've found school unbearable under those standards. And at the same time, science has progressed so much in the last few decades that there is just too much content to cover and too little time.

    Thanks for the suggestions. Actually, I think I've just found Partington's book online: https://archive.org/details/textbookofinorga00partuoft

    Just from giving it a glance, it looks a bit daunting because of the maths. Yet maybe if I take it slowly it's doable.
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    Quote Originally Posted by Matt24 View Post
    Quote Originally Posted by Strange View Post
    That's a really good question!
    Maybe you should be studying history of science (I don't know if there are specific history of chemistry books/courses). That way you get to the bottom of how these things were worked out and get a background in basic chemistry as well.

    Of course, initially people didn't know this was hydrogen. Or even that it was the same gas. Then the properties were examined (lighter than air, flammable, produces water when burned) ... seems to be the same gas. Let's call it ... well, it generates water (hydro) so lets call it hydrogen.

    So, yes, it was a long slow process of puzzling it all out.
    Yes, think I need to know about those processes to content myself. I understand why it would be pointless to teach it in school (as they probably consist of long stories of experiments and hypotheses), yet it would help inquisitive natures like me who want to know about everything.

    Indeed, probably the names of the elements can tell a lot about their function and behavior. I don't know Latin, but I know "phosphorus" is related to light (as in other languages like Spanish, matches are called "fósforos" - don't know why English didn't pick up that Latin root).

    Maybe studying Latin would be a smart move? Kind of reminds me when one of my teachers explained to me where the names of the months came from. It was an eye-opener! That's when I realized the usefulness of Greek and Latin as base languages. However, I always found them too complex to even try to learn them.

    Quote Originally Posted by Strange View Post
    These books sound so interesting!! I should check them out. Yet they sound a bit encyclopaedic. Maybe I'm wrong. But if they go from A to Z then I will read first about Aluminium (which is comparatively recent if I'm not mistaken) and only about Gold, Oxygen later (which have a greater history of research and were discovered before aluminium).

    Does one of these start from 0 knowledge? They all sound compelling though, but I haven't enough time to add that many more books on my "to-read" list.

    Thanks for your help!
    I think you'll find you can dip into these books element by element. I don't think you have to read the chapters in sequence to make sense of them.
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    Quote Originally Posted by exchemist View Post
    I think you'll find you can dip into these books element by element. I don't think you have to read the chapters in sequence to make sense of them.
    Exactly what I was going to say. I'm pretty sure I have never read the Emsley book from cover to cover (although that is the sort of thing I do). Just dipped in when I get curious about an element (e.g. when someone on a science forum claims that it will cure / kill all).
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
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    Quote Originally Posted by Matt24 View Post
    Quote Originally Posted by Warron View Post
    I think that Partington's Textbook of Inorganic Chemistry is excellent. I began with that at age 11 and am on my second copy, having worn the first one out.
    Another excellent one is Lowry and Cavell Intermediate Chemistry (1954)
    Another is Smiths Inorganic Chemistry by Kendall (1928)

    There are many more. These have all been out of print for a long time so you can only pick them up second-hand. Most second-hand book shops of reasonable size will have something that might be suitable.

    When I was a kid, we all had chemistry sets and mucked around with chemicals in the back shed. And you could buy quite a range of chemicals and equipment from chemical supply shops. Sadly, the proliferation of backyard drug labs as well as ever increasing safety regulations means that you can't do that now.

    When I finished high school in 1969, history of chemistry was still part of the first level course. It was during the 60s that the whole approach to teaching chemistry changed. The same applies to maths actually.
    Wow, it was good luck that you were in school at that time before the approach was changed. I only wish that could've happened to me! But I guess most people today would've found school unbearable under those standards. And at the same time, science has progressed so much in the last few decades that there is just too much content to cover and too little time.

    Thanks for the suggestions. Actually, I think I've just found Partington's book online: https://archive.org/details/textbookofinorga00partuoft

    Just from giving it a glance, it looks a bit daunting because of the maths. Yet maybe if I take it slowly it's doable.
    I am surprised about your comment on maths. I have never really used the book for maths.

    And while it is great to have the resource available for download (thanks for that link), it is not the same as having a book that you can dip into as you have a need or interest. Which seems to be the same as what others are saying about the other books that have been suggested.
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    Quote Originally Posted by Strange View Post
    Quote Originally Posted by exchemist View Post
    I think you'll find you can dip into these books element by element. I don't think you have to read the chapters in sequence to make sense of them.
    Exactly what I was going to say. I'm pretty sure I have never read the Emsley book from cover to cover (although that is the sort of thing I do). Just dipped in when I get curious about an element (e.g. when someone on a science forum claims that it will cure / kill all).
    Most probably I can do that. Thanks for the help guys!


    Quote Originally Posted by Warron View Post
    I am surprised about your comment on maths. I have never really used the book for maths.

    And while it is great to have the resource available for download (thanks for that link), it is not the same as having a book that you can dip into as you have a need or interest. Which seems to be the same as what others are saying about the other books that have been suggested.
    I don't know really if it's that math-y. It's 1000 pages long and I caught a glance of a page filled with drawn geometric figures. Maybe I just imagined it was geometry and it was actually something else. I'll have to read it to know.

    I agree physical books > e-books. It is easier for your eyes to tire when staring at a screen. And one is more prone to get distracted in front of a computer (I know I do that... like, "hey! I'll stop reading just for a little while to check my email". 5 minutes later I forget all about the book lol). But I guess it's more comfortable to have it on the computer than to try to find it in a library or in a bookshop.
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    Quote Originally Posted by Matt24 View Post
    Quote Originally Posted by exchemist View Post
    Well I knew when I wrote it that the apple browning one would be the most tricky. I was a bit vague about it myself. But this explanation seems fairly clear: Why Cut Apples Pears Bananas and Potatoes Turn Brown

    Interestingly, some cookery sites say (wrongly, it appears) that it is "ascorbic acid" (aka vitamin C) in lemon juice that prevents the browning. Whereas this explanation says it is just that acid - of any sort - denatures the enzyme in apples that causes the process. The main acid in lemon juice is of course citric acid (French citron = lemon). Vitamin C is present too, but at a far lower concentration.

    So we seem to have our first example of popularly believed chemical ballocks - the exposure of which is a pastime I enjoy, slightly more than is strictly healthy.
    Thanks, that was a better explanation. It's still clearer when you put it as a simple chemical molecule formula, as you did with the natural gas problem (CH4; 2O2 -> CO2 2H2O; can't get simpler than that).

    Unfortunately, those pseudoscientific articles are probably the fault of those of us with no chemistry knowledge. I would've fallen in for it as a coherent explanation! What is more, I thought that it only happened with apples (as they had iron). I never noticed it with bananas, pears or potatoes! Guess I either eat them too fast (hahahaha) or don't eat them much (don't remember the last time I ate pears, not my fruit to be honest). It's interesting that they all share a common characteristic.

    So, bottomline: maybe I just need to google better to find the simple explanations I need.
    Well yes possibly so, though I do strongly believe that without some familiarity with chemistry, it is very very easy to be put off by a needlessly complicated explanation and assume that the fault is with yourself in not being able to understand, when it is not. I think you'll find, if you read some chemistry along the lines proposed, you will be able to follow such things enough to be able to discriminate between excessively complicated explanations (those you really can't follow) and simpler ones, which you by then WILL be able to follow. If I read something on the web and can't make head nor tail of it, I shop around for one I can follow, because I have the confidence to know I should be able to follow if it is explained clearly enough. That's the advantage of knowing something about about the subject.

    And it will feed on itself - the more you read and follow, the better you will get.
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    Quote Originally Posted by exchemist View Post
    Well yes possibly so, though I do strongly believe that without some familiarity with chemistry, it is very very easy to be put off by a needlessly complicated explanation and assume that the fault is with yourself in not being able to understand, when it is not. I think you'll find, if you read some chemistry along the lines proposed, you will be able to follow such things enough to be able to discriminate between excessively complicated explanations (those you really can't follow) and simpler ones, which you by then WILL be able to follow. If I read something on the web and can't make head nor tail of it, I shop around for one I can follow, because I have the confidence to know I should be able to follow if it is explained clearly enough. That's the advantage of knowing something about about the subject.

    And it will feed on itself - the more you read and follow, the better you will get.
    Thanks for the advice! I agree, sometimes it's demoralizing to find yourself with complicated texts. After a while you subconsciously tell yourself you are not smart enough to understand, even though it's not your fault it was written in an unclear way.

    Will tell myself to keep trying when I get in that position again. Thanks for all your help again!! You'll probably see me in this forum once more in a while - hopefully having acquired more knowledge.
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    Quote Originally Posted by exchemist View Post
    Quote Originally Posted by Matt24 View Post
    I'm sorry if my question sounds too basic, but I'm a "dummy" trying to understand chemistry. When I was in high-school, chemistry kind of put me off for one big reason: that it was difficult to apply in real life most of what I had learned. Atomic theory has been partly to blame. Of course it's easy to understand, but I found difficulty in relating all I learned with the objects I interacted with. For one part, I was not familiar with 95% of the elements I found on my periodic table. So it was hard for me to accept that all matter is comprised of all these unknown substances.

    But what's particularly always baffled me, even to this day, is that my intuition does not help me accept chemistry basics. As an example, when I drop a cup of glass and it breaks, what I see on the floor in tiny pieces is still glass again. For me, in my own stupid world, glass is basically an element. And so are many other substances which I come up with in my daily routine.

    I understand that if I had a microscope, maybe I would realize what these things are made of. Yet they never told me at school if glass was comprised of this and that element. I was just supposed to accept that these mysterious elements govern my world! And things got worse and worse when I had to take in that atoms "bond", or that they have X quantity of electrons in this or that shell, without even mentioning how we know these things. But that's another matter, probably more related with the educational system of modern times.


    Anyway, now I'm motivated to start all over, and for that I want to answer each and every one of my inquiries. And this is what I really need to know before I delve deeper into atomic theory:

    What are these common substances composed of, chemically?
    - Glass
    - Wood
    - Plastic
    - Paper
    - Leather
    - Clay
    - Wool
    - Ink
    - Glue
    - Soap
    - Meat


    I would really appreciate some help. I'm trying to teach myself chemistry but it's not easy for me.

    Thanks in advance!
    John G has given an indication of how your question can be answered. But I think if I were you I would start with simple, everyday examples of chemical change , rather than the composition of complex substances.

    For example, when you burn natural gas in a cold room, why do the windows steam up?

    Why does squeezing lemon juice onto cut apples prevent them turning brown?

    Why does water expand when it freezes?

    How does washing up detergent enable water to clean a greasy plate?

    Why is vinegar good for cleaning glass without leaving streaks?

    and so on.
    I was thinking about your response today and I see where you are coming from with this. Rather than trying to take a systematic approach, pick something that is of interest and investigate that. Repeat the process. That is the learning process that happens when you use this type of forum. I am often inspired to investigate things that people raise in threads. In this way my knowledge is increased in increments. It is much easier to learn about something that interests you than to work through a whole branch of science systematically.
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  50. #49  
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    Quote Originally Posted by Warron View Post
    Quote Originally Posted by exchemist View Post
    Quote Originally Posted by Matt24 View Post
    I'm sorry if my question sounds too basic, but I'm a "dummy" trying to understand chemistry. When I was in high-school, chemistry kind of put me off for one big reason: that it was difficult to apply in real life most of what I had learned. Atomic theory has been partly to blame. Of course it's easy to understand, but I found difficulty in relating all I learned with the objects I interacted with. For one part, I was not familiar with 95% of the elements I found on my periodic table. So it was hard for me to accept that all matter is comprised of all these unknown substances.

    But what's particularly always baffled me, even to this day, is that my intuition does not help me accept chemistry basics. As an example, when I drop a cup of glass and it breaks, what I see on the floor in tiny pieces is still glass again. For me, in my own stupid world, glass is basically an element. And so are many other substances which I come up with in my daily routine.

    I understand that if I had a microscope, maybe I would realize what these things are made of. Yet they never told me at school if glass was comprised of this and that element. I was just supposed to accept that these mysterious elements govern my world! And things got worse and worse when I had to take in that atoms "bond", or that they have X quantity of electrons in this or that shell, without even mentioning how we know these things. But that's another matter, probably more related with the educational system of modern times.


    Anyway, now I'm motivated to start all over, and for that I want to answer each and every one of my inquiries. And this is what I really need to know before I delve deeper into atomic theory:

    What are these common substances composed of, chemically?
    - Glass
    - Wood
    - Plastic
    - Paper
    - Leather
    - Clay
    - Wool
    - Ink
    - Glue
    - Soap
    - Meat


    I would really appreciate some help. I'm trying to teach myself chemistry but it's not easy for me.

    Thanks in advance!
    John G has given an indication of how your question can be answered. But I think if I were you I would start with simple, everyday examples of chemical change , rather than the composition of complex substances.

    For example, when you burn natural gas in a cold room, why do the windows steam up?

    Why does squeezing lemon juice onto cut apples prevent them turning brown?

    Why does water expand when it freezes?

    How does washing up detergent enable water to clean a greasy plate?

    Why is vinegar good for cleaning glass without leaving streaks?

    and so on.
    I was thinking about your response today and I see where you are coming from with this. Rather than trying to take a systematic approach, pick something that is of interest and investigate that. Repeat the process. That is the learning process that happens when you use this type of forum. I am often inspired to investigate things that people raise in threads. In this way my knowledge is increased in increments. It is much easier to learn about something that interests you than to work through a whole branch of science systematically.
    Yes, that at any rate was how my appetite for physics and chemistry was whetted as a child. "Why does such and such happen?"…………...

    After a while you start joining the dots and then it is wonderful to realise there is a whole system underlying these phenomena.
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