How many grams of magnesium can react with 162 grams of zinc oxide?

Given:
m (ZnO) = 162 g

Find:
m (Mg) -?

Solution:
1) Write the reaction equation:
Mg + ZnO => Zn + MgO;
2) Calculate the molar masses of ZnO and Mg:
M (ZnO) = Mr (ZnO) = Ar (Zn) * N (Zn) + Ar (O) * N (O) = 65 * 1 + 16 * 1 = 81 g / mol;
M (Mg) = Mr (Mg) = Ar (Mg) = 24 g / mol;
3) Calculate the amount of ZnO substance:
n (ZnO) = m (ZnO) / M (ZnO) = 162/81 = 2 mol;
4) Determine the amount of Mg substance:
n (Mg) = n (ZnO) = 2 mol;
5) Calculate the mass of Mg:
m (Mg) = n (Mg) * M (Mg) = 2 * 24 = 48 g.

Answer: The mass of Mg is 48 g.