Question

If we have 2.500g of CuCl2•2H2O and 2.200 g of Cu to make CuCl. What is the theoretical yield?

Answer 1

You need to confirm molar masses and all the calculations. My calculator is on the blink and I've just estimated the calculations and molar masses.
CuCl2*2H2O + Cu ==> 2CuCl + 2H2O
mols CuCl2*2H2O = grams/molar mass = 2.500/170 = 0.015
mols Cu = 2.200/63 = 0.035
How much CuCl can we get with CuCl2*2H2O? That's
0.015 mols CuCl2*2H2O x (2 mol CuCl/1 mol CuCl2*2H2O) = about 0.030
How much CuCl can we get with Cu? That's
0.035 x (2 mol CuCl/1 mol Cu) = 0.070
The limiting reagent is CuCl2*2H2O; therefore, we will get about 0.030 mols CuCl from CuCl2*2H2O. Then grams CuCl = mols CuCl x molar mass CuCl = ? and this is the theoretical yield.