A young radio technician, while etching a copper-plated board, lowered it into a solution of iron (III) chloride.

A young radio technician, while etching a copper-plated board, lowered it into a solution of iron (III) chloride. What mass of copper will go into solution if, as a result of the reaction proceeding according to the equation 2FeCl3 + Cu = 2FeCl2 + CuCl2, 1.35 g of copper (II) chloride was released.

Given:
m (CuCl2) = 1.35 g

To find:
m (Cu) -?

Decision:
1) Write the reaction equation:
2FeCl3 + Cu => 2FeCl2 + CuCl2;
2) Calculate the molar masses of Cu and CuCl2:
M (Cu) = Mr (Cu) = Ar (Cu) = 64 g / mol;
M (CuCl2) = Mr (CuCl2) = Ar (Cu) * N (Cu) + Ar (Cl) * N (Cl) = 64 * 1 + 35.5 * 2 = 135 g / mol;
3) Calculate the amount of substance СuСl2:
n (CuCl2) = m (CuCl2) / M (CuCl2) = 1.35 / 135 = 0.01 mol;
4) Determine the amount of substance Cu:
n (Cu) = n (CuCl2) = 0.01 mol;
5) Calculate the mass of Cu:
m (Cu) = n (Cu) * M (Cu) = 0.01 * 64 = 0.64 g.

Answer: The mass of Cu is 0.64 g.