Question

Give an example of chemical reaction characterized by change in temperature.

Answer 1

• When Calcium oxide or quicklime $\left(\mathrm{CaO}\right)$ is reacted with water, Calcium hydroxide or slaked lime $\left(\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\right)$ is formed and a large amount of heat is released, resulting in the change in temperature in the mixture.

$$\begin{gathered} \mathrm{CaO}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to \mathrm{Ca}{\left(\mathrm{OH}\right)}_2\left(\mathrm{aq}\right)+\mathrm{Heat} \\ \left(\mathrm{Quicklime}\right)\left(\mathrm{Water}\right)(\mathrm{Slaked} \\ \mathrm{lime}) \end{gathered}$$