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Thread: Need some lesson help with formulaes

  1. #1 Need some lesson help with formulaes 
    Forum Senior Booms's Avatar
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    Ok I'm doing chemistry A-level and I'm struggling, for some reason I can't get the forumlas to stick, things like finding Mol Concentration, finding mol'dm, molg, etc etc

    when I remeber the formula it's fine I can ace the work and am top of the class, but I can't get them to stay in my head for more than the lesson


    can anyone give me any help on how to memorise them?


    It's not how many questions you ask, but the answers you get - Booms

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    Forum Masters Degree organic god's Avatar
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    Best thing to do i find is learn units. etc.

    So like if you want to find concentration. concentration is mol dm^-3

    units of mol are mols.
    units of volume are dm^3.

    so clearly to get the units to balance concentration = mol / volume

    and the obvious tip is PRACTICE.

    i know how boring it can be practising basic mol calculations but you can not progress to a high level without these skills and a high level of competence in it will be a huge benefit when you study more complex topics


    everything is mathematical.
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    ok thank's and yeah I practice constantly but that's a good point I never saw the relation between mol, dm3 and moldm3
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  5. #4  
    Forum Masters Degree organic god's Avatar
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    Usually when I get stuck on a topic i work at it and get frustrated by it, however if you keep on working at it and doing problems eventually something clicks in your head and it all makes sense, then you never forget it because of all the work you put in to get there.
    I find the feeling you get when you grasp a difficult concept is incredible and is an important part of your personal growth
    everything is mathematical.
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    Forum Sophomore oceanwave's Avatar
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    yea, i agree with the above...for me, i had a great difficulty with the stoichiometry chapter as we were given everything in formulae format without the explanation for how and why. so i kinda screwed up back then. i sat for the As too. a tip would be to understand the formulas then just memorising. that way its waaaaay easier. if ure from s'pore, i can more or less guarantee that jc1's chem has only 10% worth of stuff to memorise (that is IF u understand what ure studying) and for organic unfortunately, i've nvr found a way to memorise the reactions/conditions effectively. the closest i got to organic chem memorising/understanding was the mechanisms and the conditions etc are similar but not the same. ok, quite hazy info here. haha. wld u like tips for j1 work?
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    Forum Masters Degree organic god's Avatar
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    i just finished my A level's so i don't think i need the j1 tips but thanks anyway.

    With the organic chemistry your way is quite effective by loooking at the functional groups and seeing how they react. but the best way to learn it is to go right back to first principles when you look at your reaction, here is what i mean

    1) Draw out your organic compound.

    2) Label the areas of slightly positive/negative charge.

    3) now add your reactant to the drawing and label any charge/slightly charged areas.

    4) remember the simple rule. positive goes to negative, negative goes to positive.

    from this you can pretty much do A level organic chemistry.

    so here is one for you to try. 1-chloropropane + Pottasium Hydroxide (aqeous conditions+ reflux)

    Another thing with organic chemistry is to do lots of practice questions, but not just simple one word line questions like what is C if A reacts with B. In an exam yo will often get a wordy question of 6 lines that have lots of different reactions going on and you need to untangle the snake and lay it out straight.
    This is an excellent practice website.
    http://www.rod.beavon.clara.net/orgprobs.htm
    everything is mathematical.
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    Forum Sophomore oceanwave's Avatar
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    hahaha...i would presume on teaching u (organic god) as ur nick suggests that ur area of expertise probably lies there! hahaha....im more specialised in the area of inorganic chem; chiefly that part that is steeped in theories and how to utilise these theories to found a basis for an idea, etc. kinda like writing a thesis on the reactions/properties/nature of an element (for example: strongtium) by just looking at its location in the periodic table and using the basic knowledge, throw up many ideas about what it could be (assuming that it's still an undiscovered element).

    i also like to dig deep into the theories provided and see if they hold water (literally) and if they fail/flounder under extremities, then i would try to throw in my own theories and do some research. which (im very happy to say) occasionally shows that new research shows that the basic principles which i identified for my theory holds true. so yea. it makes chemistry waaaay more fun than say, reading a textbook and regurgitating the facts in an exam.

    one very good book to recommend is: the development of chemical principles.
    the book really stretches one's understanding of the basics and challenges simple terms that most student chemists take for granted: i.e. the definition of an element/compound. the authors show how the early chemists finally determined whether a substance was an element/compound through many experiments/thought processes and not just the simple: an element is only composed of atoms of just that element and no other. imagine if u didnt have any instruments to check that directly! how on earth would u go about creating experiments to infer that the substance really IS an element. *gushes* im only 1 chapter into the book and im totally whacked about with the complexity in the simplicity of the basic terms! but that's just me and what i like abt chem. how abt the rest of u guys out there?
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  9. #8  
    Forum Masters Degree organic god's Avatar
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    yeh that side of chemistry does sound pretty interesting, so it's more properties of matter that interest you rather than "mainstream" chem
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  10. #9  
    Forum Sophomore oceanwave's Avatar
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    i guess so...cause i honestly hate memorising reactions and conditions in organic chem (no offence to u i hope). btw, if ure interested in the book and from s'pore too, u can get it at the nearest borders bookshop. think u'll have to special order it tho (i got the only copy on the shelf )
    What do you do when the last day of your life is approaching...........?
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  11. #10  
    Forum Masters Degree organic god's Avatar
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    yeh the book does sound pretty cool, i'm in london so hopefully it won't be too hard to find =). for my physicalc chemistry i currently use atkins physical chemistry 8th edition which is pretty cool.
    haha i'm not offended, but organic chemistry isn't always just memorisation, some of the stuff you can work out if you think about it
    everything is mathematical.
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  12. #11  
    Forum Sophomore oceanwave's Avatar
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    really??? hey! please share the tips for organic chem please...im terribly scared of it esp since im entering uni nxt yr and my organic chem isnt really up to scratch...other than the mechanisms for reactions and other theory based parts, can u please teach me (and others out there) how to remember the reaction conditions required of each reaction? :-D
    What do you do when the last day of your life is approaching...........?
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  13. #12  
    Forum Masters Degree organic god's Avatar
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    At A level the main conditions you will need to be focused on are.

    solvent?
    reflux?
    heat?

    I never really learnt these specifically for each reaction but the best thing i found was to produce links between. types of reactions and conditions. for example i found that most of the alkyl halide reactions required reflux.
    I was never taught how to work out if reflux is required or not, usually if you don't want to boil off all your volatile component before it has had a chance to react.

    Seriously man just practice your ass off, try to find questions in prose form with lots of information in it, these are good fun, help you learn and similar to exam format
    everything is mathematical.
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  14. #13  
    Forum Sophomore oceanwave's Avatar
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    yeap...im done with the A's too...just hoping that u'd some special method to share. and i do not really agree with the practice practice practice mantra (esp in my country where students are perpetually mugging/cramming). i can hit all areas of chem with high grades without the usual practice even at A levels but just cant seem to do the same for organic chem...so which uni r u applying to? oxford? cambridge? was considering going overseas to do my degree but wasnt sure which country to go...
    What do you do when the last day of your life is approaching...........?
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  15. #14  
    Forum Masters Degree organic god's Avatar
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    i'm doing my first year in chemical engineering at Imperial college London at the moment. Didn't apply to oxford or cambridge.

    My strategy was just doing practice questions like i said, i think that the difficulty you may have with organic chemistry is that although you can learn certain rules there are many exceptions to the rules. don't remember a specific strat sorry
    everything is mathematical.
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