Endothermic and Exothermic Processes Practice Test

Hydrogen peroxide decomposes in the presence of a catalyst: $2\text{H}_2\text{O}_2(aq)\rightarrow 2\text{H}_2\text{O}(l)+\text{O}_2(g)$. The container warms during the reaction. Which statement is correct?

In a lab demonstration, barium hydroxide octahydrate reacts with ammonium chloride and the beaker becomes very cold, sometimes freezing water beneath it. Which statement best describes the reaction's enthalpy change?