When interacting with water, 2 g of calcium displaces gas with a volume of?

Let’s find the amount of calcium.

n = m: M.

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

n = 2 g: 56 g / mol = 0.036 mol.

Let’s compose the reaction equation:

Ca + 2H2O = Ca (OH) 2 + H2.

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

n (Ca) = n (H2) = 0.036 mol.

Let’s find the volume of hydrogen.

V = Vn n, where Vn is the molar volume of gas equal to 22.4 l / mol, and n is the amount of substance.

V = 22.4 L / mol × 0.036 mol = 0.8 L.

Answer: 0.8 l.