Calculate the amount of substance and the mass of calcium hydroxide formed by treating 11.2

Calculate the amount of substance and the mass of calcium hydroxide formed by treating 11.2 calcium oxide with excess water.

Let’s find the amount of calcium oxide substance.

n = m: M.

M (CaO) = 40 + 16 = 56 g / mol.

n = 11.2 g: 56 g / mol = 0.2 mol.

Let’s compose the reaction equation:

CaO + H2O = Ca (OH) 2.

According to the reaction equation, 1 mole of calcium hydroxide accounts for 1 mole of calcium hydroxide, that is, the substances are in quantitative ratios of 1: 1, which means their amount of substances will be the same.

n (CaO) = n (Ca (OH) 2) = 0.2 mol.

Find the mass of calcium hydroxide.

m = n × M.

M (Ca (OH) 2) = 74 g / mol.

m = 74 g / mol × 0.2 mol = 14.8 g.

Answer: 14.8 g.