You need to understand that this is a limiting reagent problem. The reason you can't use EITHER Zn or CuSO4 is because one of them will be used up before the other is; i.e., one reagent will be used and the other one will be in excess.
mols CuSO4 = 0.1
mols Zn = 3.22/65.4 = 0.049
Now use the coefficients to convert mols each to mols Cu.
For CuSO4 that is 0.1 x (1 mol Cu/1 mol CuCO4) = 0.1 mol Cu produced.
For Zn that is 0.049 x (1 mol Cu/1 mol Zn) = 0.049
You can see the mols Cu produced is NOT the same which means 0.049 mols Cu will be produced (you can't get 0.1 because there isn't enough Zn present). So Zn is the limiting reagent, all of it will be used, there will be Cu left unreacted.
So 0.049 mol Cu will be produced and that is 0.049 x 63.55 = 3.22. I don't know what numbers your answer book used to get 3.15 but my periodic table numbers give 3.22. Technically you aren't allowed but one significant figure either so the answer should be rounded to 3.
The equation is:
CuSO4(s) + Zn(s) -> Cu(s) + ZnSO4(aq)
3.22 g of powdered zinc is added to 200ml of 0.5M copper sulfate solution.
What mass of copper is deposited?
Hi guys. I am confused about the stoichmetry question.
Q: The equation is:
CuSO4(s) + Zn(s) -> Cu(s) + ZnSO4(aq)
3.22 g of powdered zinc is added to 200ml of 0.5M copper sulfate solution.
What mass of copper is deposited?
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I found the mol of CuSO4 to be 0.1 and mol of Zn to be 0.049 mol.
To figure out the mass of Cu, why can't I use either of those moles(because the coefficient are the same!)? I looked in the answer and I had to use 0.049(Zn's mol) why not CuSO4's mol as the answer is 3.15g Please let me know. Thanks so much!
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