Copper (i) oxide, cu2o, is reduced to metallic copper by heating in a stream of hydrogen gas. what mass of water is produced when 10.00 g copper is formed?

Answer is: mass of water is 1.41 g.

Balanced chemical reaction: Cu₂O + H₂ → 2Cu + H₂O.

m (Cu) = 10.00 g.

n (Cu) = m (Cu) : M (Cu).

n (Cu) = 10 g : 63.55 g/mol.

n (Cu) = 0.157 mol.

From chemical reaction: n (Cu) : n (H₂O) = 2 : 1.

n (H₂O) = 0.079 mol.

m (H₂O) = n (H₂O) · M (H₂O).

m (H₂O) = 0.079 mol · 18 g/mol.

m (H₂O) = 1.41 g.