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Topic: calculating precent by volume  (Read 4497 times)

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Offline caelab

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calculating precent by volume
« on: December 04, 2007, 07:18:03 PM »
hey guys i am having trouble with this chemisty problem if you could help that would be great. here is the question:

you are given a can of frozen grape juice: 355mL add 3 cans cold water mix vigorously, ingredients: sugar water concentrated grape juice 500mg of ascorbic acid(C6H9O6). if you follow the instructions on the preceding juice can for preparing the grape juice, what is the new concentration of the grape juice compared to the original frozen can in percent by volume? (show all calculations necessary)

Offline constant thinker

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Re: calculating precent by volume
« Reply #1 on: December 04, 2007, 08:32:38 PM »
Number 4 on this website will help.

I'll even give you a hint. Start by finding your initial concentration. Then find out what your ending concentration is. From there you can compare the two concentrations.
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Offline caelab

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Re: calculating precent by volume
« Reply #2 on: December 05, 2007, 11:31:34 AM »
ok so what i've done so far is this: C=0.500 g/0.355 L which gives me 1.41 g/L. am i sapposed to use the sugar to help me calculate the concentration of the grape juice?

Offline Bob Mahoy

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Re: calculating precent by volume
« Reply #3 on: December 05, 2007, 11:38:11 AM »
*deleted*
« Last Edit: December 05, 2007, 11:51:30 AM by Bob Mahoy »

Offline Bob Mahoy

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Re: calculating precent by volume
« Reply #4 on: December 05, 2007, 11:48:21 AM »
In the <B>original</B> can of grape juice there was 500mg acsorbic acid along with sugar and water. Both the sugar and the acid have been dissolved and therefore do not affect volume.

*I just realized that I haven't taken into account the resulting change in volume from solid water to liquid water. If you think it's important, than I suggest that you find it.*

As the mass of ascorbic acid is given, we can use it to find the original concentration as you gave. (1.41 g/L)

The cans of water that are added are the same volume as the original can, therefore the final volume of the solution will be 355ml + 3(355mL) or 355ml * 4 which equals 1420ml or 1.42 L.

No extra solutes are added in the the latter solution, only the solvent water. The final concentration will simply be .5g/1.42L = .352 g/L

To finish the problem, find the percentage concentration of the final solution relative to the frozen can. 0.352g/L / 1.41g/L = 31% percent
« Last Edit: December 05, 2007, 12:08:37 PM by Bob Mahoy »

Offline Bob Mahoy

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Re: calculating precent by volume
« Reply #5 on: December 05, 2007, 11:50:04 AM »
*Double Post*
« Last Edit: December 05, 2007, 12:09:16 PM by Bob Mahoy »

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