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### Topic: Would Appreciate some help(Actual Yeild)  (Read 6955 times)

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#### yitriumm

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##### Would Appreciate some help(Actual Yeild)
« on: December 18, 2007, 01:26:09 AM »
Hi all.
I am having trouble with an assignment and would appreciate a little help.

I need to calculate the actual yield of copper in this equation using the following data and am unsure as to how to go about it.
I have calculated the theoretical yield of copper to be 0.745 g Cu.

3CuCl2*2H2O(aq)+2 Al(s)->3Cu(s)+2AlCl3(aq)+6H2O(l)

copper salt
2.00g
filter paper
0.97g
beaker 1
67.80g
beaker1 with copper salt
69.80g
beaker two
67.32
beaker two with dried copper salt and filter paper(after reaction has occured)
69.54g

I know the actual yield can't be more then the theoretical yeild however the answer I keep getting is higher.
Any help would be appreciated!
« Last Edit: December 18, 2007, 03:39:48 AM by yitriumm »

#### Dan

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##### Re: Would Appreciate some help(Actual Yeild)
« Reply #1 on: December 18, 2007, 03:43:49 AM »
I agree with your value for theoretical yield.

The copper product was probably just wet. How did you dry it?
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#### yitriumm

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##### Re: Would Appreciate some help(Actual Yeild)
« Reply #2 on: December 18, 2007, 03:44:49 AM »
I edited the mass in. It was air dried after being reacted in beaker one and being moved to beaker two.

#### Dan

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##### Re: Would Appreciate some help(Actual Yeild)
« Reply #3 on: December 18, 2007, 03:50:45 AM »
Put it in an oven at 100 degrees for a couple of hours, or wash it with acetone and then air dry.

That said it is rather a large discrepancy, you have a 168% yield which is rather high to blame on being wet...

My research: Google Scholar and Researchgate

#### yitriumm

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##### Re: Would Appreciate some help(Actual Yeild)
« Reply #4 on: December 18, 2007, 03:52:34 AM »
Unfortunately the experiment is at school. However that is the actual yield that I calculated and I am rather surprised that it's the correct answer. I was sure it was wrong. Thanks for the help =]

#### yitriumm

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##### Re: Would Appreciate some help(Actual Yeild)
« Reply #5 on: December 18, 2007, 03:56:49 AM »
I calculated an answer of 1.25 for actual yield which in turn I used to calculate the percentage yield of 168%. The number seemed so off, thus I was unsure. In regards to this question, what mass of copper is formed when excess of aluminum is reacted with a given mass of copper 2 chloride dihydrate. I calculated 1.1000g as the answer.

#### Dan

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##### Re: Would Appreciate some help(Actual Yeild)
« Reply #6 on: December 18, 2007, 04:06:20 AM »
I calculated an answer of 1.25 for actual yield which in turn I used to calculate the percentage yield of 168%. The number seemed so off, thus I was unsure.

1.25 g (168%) is the yield that you get from the numbers you have given. You are right to be unsure because the maximum yield of copper you could get is 0.75 g (100%). It is a problem with your experiment, such as a wet product, not with the maths.

Quote
In regards to this question, what mass of copper is formed when excess of aluminum is reacted with a given mass of copper 2 chloride dihydrate. I calculated 1.1000g as the answer.

What is the "given mass of copper 2 chloride dihydrate"? Can't check the answer without it.

I have to go now, hopefully someone else will take over if you have more questions.
My research: Google Scholar and Researchgate

#### yitriumm

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##### Re: Would Appreciate some help(Actual Yeild)
« Reply #7 on: December 18, 2007, 04:09:33 AM »
The given mass is 2.00g. Thanks for your time!

#### DrCMS

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##### Re: Would Appreciate some help(Actual Yeild)
« Reply #8 on: December 18, 2007, 04:39:15 AM »
I calculated an answer of 1.25 for actual yield which in turn I used to calculate the percentage yield of 168%. The number seemed so off, thus I was unsure. In regards to this question, what mass of copper is formed when excess of aluminum is reacted with a given mass of copper 2 chloride dihydrate. I calculated 1.1000g as the answer.

The given mass is 2.00g. Thanks for your time!
You said you calculated the yield to be 0.745g Cu how have you now got 1.1g?

How much Al did you use?  Is that 2moles for every 3 moles of copper chloride?  If not what happens to the rest?

#### yitriumm

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##### Re: Would Appreciate some help(Actual Yeild)
« Reply #9 on: December 18, 2007, 04:55:12 AM »
They were two separate questions given. For one it was asking for the mass and the   other it was asking for actual yield. I didn't think they were the same things?
The amount of Aluminum used was an 8cm by 8 cm coiled into a loop.

Quote
Is that 2moles for every 3 moles of copper chloride?  If not what happens to the rest?

#### AWK

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##### Re: Would Appreciate some help(Actual Yeild)
« Reply #10 on: December 18, 2007, 11:21:42 AM »
Show your procedure and calculations, not data.
And separate your problems clearly. I do hope you can calculate mases of reagents properly.
AWK