According to the chemical equation

2CuCl_2(s) + 4KI_(s) ---> 2CuCl_(s) + 4KCl_(s) + I_2(s)

c) how many grams of copper(II) chloride must react, assuming excess KI, to form 8.11 x 10^-3 grams potassium chloride?

Answer

This problem is similar to the first problem in this group. Once again the amount of starting material is given in grams and not moles. To solve this problem we must first convert the mass of potassium chloride to moles using the molar mass of potassium chloride. Then we can use the stoichiometric factor to convert from moles of potassium chloride to moles of copper(II) chloride. This stoichiometric ratio is obtained from the balanced chemical equation. According to the balanced chemical equation four mol of potassium chloride react to form 2 mol of copper(II) chloride. Potassium chloride and copper(II) chloride always combine in this ratio according to this equation. After determining the moles of copper(II) chloride we can convert moles to grams of copper(II) chloride using the molar mass of copper(II) chloride.