Explain how endothermic and exothermic reactions relate to the law of conservation of energy and the breaking and reforming of bonds.

Methane combustion occurs according to the equation: \( \text{CH}_4(g) + 2\text{O}_2(g) \rightarrow \text{CO}_2(g) + 2\text{H}_2\text{O}(g) \), \( \Delta H = -890 \text{ kJ mol}^{-1} \). Which statement best explains how this reaction relates to the law of conservation of energy?

The reaction between hydrogen and oxygen to form water is represented by the equation: 2H₂(g) + O₂(g) → 2H₂O(l) ΔH = -572 kJ mol⁻¹ Explain how this exothermic reaction is consistent with the law of conservation of energy.