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# Chemistry help Watch

1. Can someone help me with number 5b and explain how we get that I missed a couple of classes and I have no clue
2. Percentage yield= how much you got
--------------------------------(divided by) (x100)
how much could possibly be made
3. (Original post by hxfsxh)
Percentage yield= how much you got
--------------------------------(divided by) (x100)
how much could possibly be made
The answer is 86.9% in the book with no explanation
9.20/16.08= 0.547x100= 54.7% is wrong
4. (Original post by vickie89uk)
The answer is 86.9% in the book with no explanation
9.20/16.08= 0.547x100= 54.7% is wrong
Right give me a sec, I'll re-read the question
5. (Original post by hxfsxh)
Right give me a sec, I'll re-read the question
Thank you
6. (Original post by vickie89uk)
Thank you
I did this topic just a few months ago, but I'm totally lost as to how to get the answer. It could be the difference between NaHCO3 and Na2CO3, but I'm lost :/
7. (Original post by vickie89uk)
The answer is 86.9% in the book with no explanation
9.20/16.08= 0.547x100= 54.7% is wrong
8. (Original post by samb1234)
the answer is in the answers section I don't know how to get either of the answers I'm confused

(Original post by hxfsxh)
I did this topic just a few months ago, but I'm totally lost as to how to get the answer. It could be the difference between NaHCO3 and Na2CO3, but I'm lost :/
So Am I don't worry thanks though
9. (Original post by vickie89uk)
the answer is in the answers section I don't know how to get either of the answers I'm confused

So Am I don't worry thanks though
So it's a thermal decomposition reaction. That means that the only reactant on the left hand side of the reaction is NaHCO3, and we know that one of the products is Na2CO3. What can we tell about the number of NaHCO3 there must be, and what else could be produced which would help us to balance the equation
10. I can do part a but I'm lost on b :/
11. (Original post by surina16)
I can do part a but I'm lost on b :/
I'll get to part b in a minute , but there's no point explaining it until you understand part a
12. (Original post by samb1234)
I'll get to part b in a minute , but there's no point explaining it until you understand part a
is it anything to do with moles? that's all I can do on it haha
13. (Original post by surina16)
is it anything to do with moles? that's all I can do on it haha
indeed it is
14. (Original post by samb1234)
indeed it is
15. (Original post by samb1234)
So it's a thermal decomposition reaction. That means that the only reactant on the left hand side of the reaction is NaHCO3, and we know that one of the products is Na2CO3. What can we tell about the number of NaHCO3 there must be, and what else could be produced which would help us to balance the equation
Have we lost hydrogen so NA2CO3 + H20 (water vapour) + CO2

As water vapour and carbon dioxide are products of the reaction
16. (Original post by vickie89uk)
Have we lost hydrogen so NA2CO3 + H20 (water vapour) + CO2

As water vapour and carbon dioxide are products of the reaction
You're correct, you just need to realise what that means about the left hand side of the equation
17. (Original post by samb1234)
You're correct, you just need to realise what that means about the left hand side of the equation
I don't know what that means for the left I thought we had then gained oxygen but I don't know
18. First you need to balance the equation. So it would become
2NaHCO3 -------> Na2CO3 + H2O + CO2
19. (Original post by vickie89uk)
I don't know what that means for the left I thought we had then gained oxygen but I don't know
If you have Na2co3 and h2o there must have been 2 nahco3 in the first place, make sense?
20. (Original post by Nikitha13)
First you need to balance the equation. So it would become
2NaHCO3 -------> Na2CO3 + H2O + CO2
Yep I've got that

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