Chapter 6.7, Problem 6.10E

Manganese metal can be obtained by reaction of manganese dioxide with aluminum.

$4\text{Al}(s)+3{\text{MnO}}_2(s)\to 2{\text{Al}}_2{\text{O}}_3(s)+3\text{Mn}(s)$

What is ΔH for this reaction? Use the following data:

$\begin{array}{ccc}2\text{Al}(s)+\frac{3}{2}{\text{O}}_2(g)& \to & {\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}(s);\Delta H=-1676\text{kJ}\\ \text{Mn}(s)+{\text{O}}_2(g)& \to & {\text{MnO}}_2(s);\Delta H=-520\text{kJ}\end{array}$