The oxidation of copper (I) oxide, Cu 2 O (s), to copper (II) oxide, CuO (s), is an exothermic process. 2 Cu 2 O (s) + O 2 (g) ⟶ 4 CuO (s) Δ H ∘ rxn = - 292.0 kJ mol Calculate the energy released as heat when 9.94 g Cu 2 O (s) undergo oxidation at constant pressure.

The energy released as heat when 9.94 g Cu 2 O (s) undergo oxidation at constant pressure is - 10.142 kJ

Explanation:

Here we have

2Cu₂O (s) + O₂ (g) ⟶ 4 CuO (s) Δ H ∘ rxn = - 292.0 kJ mol

In the above reaction, 2 Moles of Cu₂O (copper (I) oxide) react with one mole of O₂ to produce 4 moles of CuO, with the release of - 292.0 kJ/mol of energy

Therefore,

1 Moles of Cu₂O (copper (I) oxide) react with 0.5 mole of O₂ to produce 2 moles of CuO, with the release of - 146.0 kJ of energy

We have 9.94 g of Cu₂O with molar mass given as 143.09 g/mol

Hence the number of moles in 9.94 g of Cu₂O is given as

9.94/143.09 = 6.95 * 10⁻² moles of Cu₂O

6.95 * 10⁻² moles of Cu₂O will therefore produce 6.95 * 10⁻² * - 146.0 kJ mol or - 10.142 kJ.