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Topic: How much water can be removed from a wet organic phase using MgSO4  (Read 9236 times)

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Offline christina

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How much water can be removed from a wet organic phase using MgSO4
« on: September 22, 2007, 12:52:40 PM »
Calculate the weight of water that can be removed from a wet organic phase using 50.0g of magnesium sulfate. Assume that it gives the hydrate listed in table 12.2

table says
hydrated: MgSO4.7H20

I'm not quite sure how I would go about this b/c when drying a organic layer you just scoop a bunch of drying agent into the test tube without measuring.

But I think that this is a simple stoichiometric calculations...is it?
If it is it would be:

50.0g MgSO4(1mol MgSO4/1.19e2g)(7mol water/1mol MgSO4)(1.80e1g/1mol water)=

5.29g water 
 ???
« Last Edit: September 22, 2007, 04:27:34 PM by ~christina~ »
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Offline Borek

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Re: How much water can be removed from a wet organic phase using MgSO4
« Reply #1 on: September 22, 2007, 01:31:23 PM »
It is simple stoichiometry. Check your math. Approach seems OK, but the result is wrong.
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Offline christina

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Re: How much water can be removed from a wet organic phase using MgSO4
« Reply #2 on: September 22, 2007, 04:26:24 PM »
I did it again and I found that the conversion was forgotten since I went from mg=> g which isn't legal...so now I got

52.94mg of water can be absorbed...Is this okay? it looks alright to me but you never know...


Thanks =)
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Offline Borek

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Re: How much water can be removed from a wet organic phase using MgSO4
« Reply #3 on: September 22, 2007, 04:45:58 PM »
Digits are OK, units are wrong. Think about it - molar mass of MgSO4 is 120 g, there are 7 moles of water per each mole of magnesium, each mole of 18 grams - no matter what is exact mass of this water it will be measured in grams, not in miligrams. You don't have to know exact result to see that something is wrong with your answer.
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Offline christina

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Re: How much water can be removed from a wet organic phase using MgSO4
« Reply #4 on: September 22, 2007, 06:28:35 PM »
Thank You
I got the answer when I did the question over again...the reason I was confused with the units was b/c I typed 50.0g instead of 50.0mg.

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