Question

When 12.5 g of copper are reacted with an excess of chlorine gas, 24.5 g of copper II chloride were obtained experimentally. Calculate the theoretical yield and the percent yield.

Answer 1

molar mass of Cu = 63.5 g/mol
number of mole of Cu = (given mass of Cu)/(molar mass of Cu)
= 12.5/63.5
= 0.197 mole

reaction taking place is
Cu + Cl2 --> CuCl2
according to reaction
1 mol of Cu give 1 mol of CuCl2
0.197 mol of Cu give 0.197 mol of CuCl2
number of mole of CuCl2 formed theoretically = 0.197

molar mass of CuCl2 = 134.5 g/mol
mass of CuCl2 formed theoretically = (number of mole of CuCl2 formed theoretically)*(molar mass of CuCl2)
= 0.197*134.5
= 26.5 g

%yield = {(actual yield of CuCl2)/(theoretical yield of CuCl2)}*100
= (24.5/26.5)*100
= 92.5 %

Answer : 92.5 %