Posted by Marc on .
so if the equation I'm using is 3CuSO4+2AL(NO3)3 arrow 3CU(NO3)2+Al2(SO4)3 how many moles of CuSO4 would be needed to produce 8 moles of Al2(SO4)3? Would the answer be 8?

Chemistry 
DrBob222,
3CuSO4+2AL(NO3)3 arrow 3CU(NO3)2+Al2(SO4)3
Let me correct the equation.
3CuSO4 + 2Al(NO3)3 ==> 3Cu(NO3)2 + Al2(SO4)3.
You want 8 moles Al2(SO4)3.
Let's just suppose you want 1 mol Al2(SO4)3. So you will need 3 mols CuSO4 because the equation tells you that. Suppose you want 2 mols Al2(SO4)3, you will need 6 moles CuSO4.
Suppose you want 3 mols Al2SO4)3, you will need 9 moles CuSO4. See how its done.
Just for practice, let's take the 3 mols Al2SO4)3 we want.
So 3 moles Al2(sO4)3 x [3 mols CuSO4/1 mole Al2(SO4)3]= 9 mols CuSO4 needed to produce 3 moles Al2(SO4)3.
Now you know how to solve the problem. Note how the units we don't want (that's Al2(SO4)3) cancel and the unit we want to convert to (that's CuSO4) stays. It always works this way. Just watch the units and set up the conversion factor so the unit you don't want cancels and the unit you want to convert to stays. So 8/3 must be the answer?? Check my work.