What mass of Cu (s) would be produced if 0.40 mol of Cu2O (s) was reduced completely with excess H2 (g) ?

50.8g

Explanation:

Given parameters:

Nubmer of mole of Cu₂O = 0.4mol

Unknown:

Mass of Cu produced = ?

Solution:

The balanced reaction equation:

Cu₂O + H₂ ⇄ 2Cu + H₂O

From the reaction, we know that:

1 mole of Cu₂O produced 2 moles of Cu

0.4 mol of Cu₂O would give 0.8mol of Cu

Now we know the number of moles of Cu produced because the limiting reactant here is Cu₂O. It was used up in the reaction in which the hydrogen gas was in excess.

To find the mass of Cu produced, we use the equation below:

Mass of Cu = Number of moles of Cu x molar mass of Cu

Molar mass of Cu = 63.5gmol⁻¹

Mass of Cu = 0.8 x 63.5 = 50.8g