Calculate the mass of hydrogen, which is formed by the interaction of calcium with 36.5 g of hydrochloric acid.

Given:

m (HCl) = 36.5 g

To find:

m (H2) -?

Solution:

2HCl + Ca = CaCl2 + H2, – we solve the problem based on the composed reaction equation:

1) Find the amount of hydrochloric acid that has reacted:

n (HCl) = m: M = 36.5 g: 36.5 g / mol = 1 mol.

2) We compose a logical expression:

If 2 mol HCl gives 1 mol H2,

then 1 mol of HCl will give x mol of H2,

then x = 0.5 mol.

3) Find the mass of hydrogen released during the reaction:

m (H2) = n * M = 0.5 mol * 2 g / mol = 1 g.

Answer: m (H2) = 1 g.