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1. i have been given a question with the actual yield and it is asking me to work out the percentage yield: 13.5g calcium oxide from heating 25g calcium carbonate i have been given an answer of 98% can someone explain to me how this is the answer and what to do to calculate other similar questions please reply asap i have a test tomorrow on this
2. (Original post by zakya)
i have been given a question with the actual yield and it is asking me to work out the percentage yield: 13.5g calcium oxide from heating 25g calcium carbonate i have been given an answer of 98% can someone explain to me how this is the answer and what to do to calculate other similar questions please reply asap i have a test tomorrow on this
It's not. Can you post the full question? (preferably a picture)
3. Attachment 469979469981Attachment 469979469981
Attached Images

4. sorry it took so long the second picture given are the answers to a b and c
5. So if CaCO3 has an Mr of 100, 25g of it is going to be 0.25 mol...

CaCO3 reacts to form CaO and CO2 at an even 1:1 ratio...

CaO has an Mr of 56 so 13.5g of it is going to be 13.5 / 56 = 0.241071428571428571428571428571 43 mol = 0.24 mol...

0.24 mol / 0.25 mol = 0.96 or 96% if you multiply by 100.

I can't see why the answer is given as 98%.
6. (Original post by zakya)
sorry it took so long the second picture given are the answers to a b and c
Is there an accompanying equation? It's been a while since I've done this... Would I be right in saying that this equation is correct:

CaCO3 ------> CaO + CO2

I don't see how the answer can be 98 percent.
7. yeah that is the equation but im not seeing how it i 98
8. i tried it and i got 96%
9. (Original post by zakya)
yeah that is the equation but im not seeing how it i 98
(Original post by zakya)
i tried it and i got 96%
I think the book is wrong in this particular case; 98 isn't that far from 96 so it could easily be a misprint. I'm getting 96 as well so I think we can more or less agree that the book is wrong on this.
10. Find moles of reagent. n=m/M

ratio
if e.g. 1:2 double, if 2:1 half, if 1:3 triple and so on

Find mass of desired product. m=nM

= theoretical maximum mass

/actual mass

x100%

I think that's the method.

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Updated: October 18, 2015
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