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Thread: dissolving sugar!!!

  1. #1 dissolving sugar!!! 
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    can anyone suggest a easy method of checking how much sugar has dissolved in about 20mls of water?


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  3. #2  
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    There are hundreds, maybe thousands, of published methods. It depends so much on your available equipment, concentration, automation techniques, and so on. You can use spectroscopy, rotation of polarized light, specific gravity, chemical reactions, colorimetry, biological activity (see Warburg apparatus), and so on.

    Tell us of your capability and limitations. We'll help you choose a method. Oh yeah, there are numerous "sugars." Sucrose, I presume?


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    Why the sugar solubility obsession ? Have you tried Canderell arm patches?
    Es ist Zeit für sauberen



    You guys
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  5. #4  
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    i have access to a triple beam balance, thermometer and basically all standard laboratory equipment.
    by sugars i mean caster sugar, white sugar and icing sugar.
    thnx for your help :wink:
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  6. #5  
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    If you dissolve white sugar in water and then put it through filter paper will the filter paper tke out the sugar from the solution?
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  7. #6  
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    No, the sugar will all pass through the filter paper.

    BTW, all the sugars that you listed are forms of sucrose, or table sugar, cane sugar, beet sugar, etc. Use the name sucrose to distinguish your samples from other common sugars such as glucose and fructose.

    The fact that it is sucrose makes it difficult to come up with a simple assay. Laboratories that routinely do such sucrose assays use an instrument called a polarimeter, or saccharometer. It measures something involving polarized light. Analyses are quick and easy. I doubt if you have one.

    Try this link and see if the method is for you:

    http://www.glue.umd.edu/~nsw/ench485/lab9d.htm

    You will need a common laboratory instrument called a spectrophotometer, or even the simpler colorimeter.
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  8. #7  
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    thanks a lot for your help
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  9. #8  
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    BTW if you put the solution in a evaporating basin the water will evaporate and the sugar will be left behind right?
    and is it the same for icing and caster sugar??? :-D
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    Yes, that is exactly right! And it may turn out that this method is the only one suitable for your level of experience and lab equipment. But it would work!
    and is it the same for icing and caster sugar???
    Yes, because these are all the same chemicals. They are all forms of sucrose, merely ground up to a different degree.

    So it is indeed possible to determine the original amount of sugar in solution simply by evaporating the water, and then weighing the dried sugar that remains. You would then have the additional advantage of being able to recover the pure sugar for further use or storage. Of course, it would be in crystalline form rather than powdered.

    Give this method as your final answer. Best of all, you thought of it by yourself!

    (BTW, nice meeting you.)
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  11. #10  
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    Quote Originally Posted by SteveF
    Yes, that is exactly right! And it may turn out that this method is the only one suitable for your level of experience and lab equipment. But it would work!
    and is it the same for icing and caster sugar???
    Yes, because these are all the same chemicals. They are all forms of sucrose, merely ground up to a different degree.

    So it is indeed possible to determine the original amount of sugar in solution simply by evaporating the water, and then weighing the dried sugar that remains. You would then have the additional advantage of being able to recover the pure sugar for further use or storage. Of course, it would be in crystalline form rather than powdered.

    Give this method as your final answer. Best of all, you thought of it by yourself!

    (BTW, nice meeting you.)
    Steve

    I left chemistry behind about 20 years ago, so this is probably going to be entirely wrong, but I'm trying anyway...

    Would it, in theory be possible to do the following:

    1. Assume that the solution is purely water and sucrose.

    2. Accurately measure the volume.

    3. Use an hydrometer to measure specific gravity

    4. Multiply results from 2 and 3.

    5. Subtract from 4 the amount of water by weight (at 1 gm/cc) based upon 2. This should give the amount of sucrose by weight.

    Or not, of course. I suppose a lot will depend upon how accurately the measurements can be taken - otherwise the error bar will swamp any results.

    What do you think?

    cheer

    the sunshine warrior
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  12. #11  
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    Hi Sunny. Yes, the method you suggested is certainly on the right track. It is indeed the method used by breweries and distilleries to track the progress of fermentation. It is quick and easy, requiring no chemistry.

    Actually they only use your Step 3. Once they get a reading for specific gravity they turn to the tables, which give the concentration of the sugar in solution. These values are corrected for temperature and alcohol, naturally.

    I dunno where you get your calculations. They are quite meaningless. Of course, you could mix a series of sucrose solutions and devise your own tables. Cheers.
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  13. #12  
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    Steve

    Thanks for that. I have even older memories (from back in the '70s) when my folks started making wine at home (very Abigail's Party!!!). Since my Dad worked for a large pharmaceuticals firm, he managed to bring home all sorts of weird and wonderful tubing for airlocks and a long, beautiful hydrometer. He also carefully explained to me that, no matter how close they seemed, specific gravity is not the same as density!

    I wonder if you can make up tables yourself using molar tables or some such (or am I barking up the wrong tree)?

    BTW: I chose the wrong bloomin' screen name. Shanks will do.
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  14. #13  
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    Hi Shanks.

    Yes, you can try to invent your own tables based purely on theoretical considerations. Lotsa luck. Trust them not.

    If you start with a precisely measured volume of water and start dumping in solute, the volume of the solution is not what it used to be. The change isn't very much but recall that your measurements of specific gravity require accuracy in parts per thousand.

    If you want to fool around with this business at home you can buy a cheap and accurate hydrometer at pet stores. They cost only a few bucks. Aquarists use them to keep track of the salinity of salt water fish tanks.

    -- Steve.
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  15. #14  
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    Quote Originally Posted by SteveF
    Hi Shanks.

    Yes, you can try to invent your own tables based purely on theoretical considerations. Lotsa luck. Trust them not.

    If you start with a precisely measured volume of water and start dumping in solute, the volume of the solution is not what it used to be. The change isn't very much but recall that your measurements of specific gravity require accuracy in parts per thousand.

    If you want to fool around with this business at home you can buy a cheap and accurate hydrometer at pet stores. They cost only a few bucks. Aquarists use them to keep track of the salinity of salt water fish tanks.

    -- Steve.
    Ha ha! Thanks. I might just try that - get the vodka levels just right (sugars, I'm not dealing with sugars - I want their products dagnabbit!)

    cheer

    shanks
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  16. #15 Re: dissolving sugar!!! 
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    Quote Originally Posted by science_bimbo
    can anyone suggest a easy method of checking how much sugar has dissolved in about 20mls of water?
    You could take a small sample such as 10 ml, evaporate the water and then the remaining sample could just be plugged and chugged...

    10 ml = number of mg
    ------- ------------------
    container size = contained mg

    However this will give you the total amount of solutes present. However other methods such as boiling point will just do the same, and your ATM conversion will be just another variable...
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