Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: JessePinkman on September 01, 2015, 02:54:38 PM
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The assignment is as follows (paraphrased): What percentage of a given amount of flakes constitutes sugar?
How would I go about answering this question? I suppose I would have to seperate the sugar from the flakes. I read up on different methods for accomplishing just that but none of them were adequate and "easy" enough to perform on a limited time frame, which is just what we will be doing.
Can I compute the percentage by the grams of the sugar and the flakes (once I know how to find out how much sugar there is in the first place, that is!)? Is that a good idea? ???
Thank you to whoever is silly enough to reply to this, I am eagerly looking forwards to my salvation.
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Flakes of what?
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What kind of flakes?
Cereal? as in Sugar Frosted Flakes?
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if you weigh a set amount of the flakes in a coffee maker filter then add water to dissolve all sugars and salts then filter through the coffee filter (possibly several times), the sugars and salts would be extracted in the water and pass through filter while insoluble starch, fibre and proteins from flakes would remain inside filter. Then you weigh sugar and salt solution in a preweighed glass and then place in oven at 105 oC to evapourate all water and reweigh once completely dry (constant weight no longer decreasing). Remaining will be the total solids (sugar + any salts). If you then place glass back in oven and set oven to auto clean which is typically 550-600 oC, it will combust all sugar while any inorganic salts (mainly sodium chloride) will remain. Take this weight measurement, and this is your total ash (salts). Subtracting this from the total solids (sugar + salt) will give you your sugar amount and then dividing by the original cereal sample size x 100 will give you the percentage of sugar in the cereal.
Your possible source of error might be in extracted water-soluble proteins also being in the solution with the sugar and salts, but this will likely not lead to a huge overestimation of your sugars, as most proteins will be bound up with the insoluble starch and fibre in the cereal flakes. There are more precise ways to do this, but for a home experiment, this will give you fairly reliable results with very basic equipment.
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Yes, cereal (specifically Kellogg's Frosted Flakes, translate that into chemistry jargon however you please ::)), everyone! Sorry for being unclear.
I am amazed by the quick replies. Thank you very much. :o
I'm in no position to evaluate which shade of great your answer is, Furanone, but it sure is absolutely terrific. I'm afraid we won't be able to utilize coffee makers, though... Is there an alternative for a simple layperson of few needs such as me myself?
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... I'm afraid we won't be able to utilize coffee makers, though... Is there an alternative for a simple layperson of few needs such as me myself?
You do not have to use the coffee maker
Just use the filter paper
If you need support for the filter paper you could use a common funnel.