Chapter 10, Problem 76E

How much energy is required to decompose $1.42\text{g}$ of ${\text{KClO}}_{\text{3}}$ according to the following equation: $2{\text{KClO}}_{\text{3}}\left(\text{s}\right)\to 2\text{KCl}\left(\text{s}\right)+3{\text{O}}_{\text{2}}\left(\text{g}\right)$? ${\text{Δ}}_{\text{r}}\text{H}=\text{89}\text{.5}\text{kJ}$ for the reaction.