[jrrumfelt]

I was given four molecular equations to balance. the next question states, "based on your balanced equation in #1, if 0.150g of copper was used to begin the experiment, calculate the mass of zinc required to reduce the CuSO4 obtained.(assume 100% completion of all intermediate steps and that no Zn(s) is lost in competing reactions.) show all work."
the balanced equations are
#1. Cu(s)+4HNO3(aq)=Cu(NO3)2(aq)+2NO2(g)+2H2O(l)
#2. Cu(NO3)2(aq)+2NaOH(aq)=Cu(OH)2(s)+2NaNO3(aq)
#3. CuO(s)+H2SO4(aq)=CuSO4(aq)+H2O(l)
#4. CuSO4(aq)+Zn(s)=Cu(s)+ZnSO4(aq)

Idont even know how to start this problem can someone help.

[Borek]

http://www.chembuddy.com/?left=balancing-stoichiometry&right=stoichiometric-calculations

[sdekivit]

i don't get this question because of reaction #3. If you obtain CuSO4 according to these reaction how can CuO react with H2SO4 when in reaction #2 Cu(OH)2 is obtained ?

[Alberto_Kravina]

Idont even know how to start this problem can someone help.

Well, start with the reaction equation. Copper(2+) + Zink ? Zink(2+) + Copper

If you have the reaction equation calculate how many moles of Zn you need to reduce a mole of copper. Then convert moles in mass (n=m/M)

Edit: Borek was faster

2nd Edit:

i don't get this question because of reaction #3. If you obtain CuSO4 according to these reaction how can CuO react with H2SO4 when in reaction #2 Cu(OH)2 is obtained ?

I think that you should focus on reaction #1 and forget the others.

[sdekivit]

(assume 100% completion of all intermediate steps and that no Zn(s) is lost in competing reactions.) show all work."
the balanced equations are
#1. Cu(s)+4HNO3(aq)=Cu(NO3)2(aq)+2NO2(g)+2H2O(l)
#2. Cu(NO3)2(aq)+2NaOH(aq)=Cu(OH)2(s)+2NaNO3(aq)
#3. CuO(s)+H2SO4(aq)=CuSO4(aq)+H2O(l)
#4. CuSO4(aq)+Zn(s)=Cu(s)+ZnSO4(aq)

do you think you should forget all the other reactions ? From this quote i think we need to take into account all the reactions that yield CuSO4 in this process. And thus then i'm stuck on reaction #3.

[Borek]

Looks like it is a "process" where next step starts with the product of the previous one. Cu(OH)₂ -> CuO is missing, but my take is that it doesn't matter.

jrrumfelt: assuming every next reaction uses product from the previous one, how much copper is used as a reactant in the 4^th reaction?

[sdekivit]

Looks like it is a "process" where next step starts with the product of the previous one. Cu(OH)₂ -> CuO is missing, but my take is that it doesn't matter.

i agree with this. Overall stoichiometry Cu : CuSO4 will be 1:1.