Chapter 9, Problem 9.89PAE

9.89 A sample of gas is 80.0% ${\text{CH}}_{\text{4}}$ and 20.0% ${\text{C}}_{\text{2}}{\text{H}}_{\text{6}}$ by mass. What is the heat from the combustion of 1.00 g of this mixture? Assume the products are ${\text{CO}}_{\text{2}}$ (g) and ${\text{H}}_{\text{2}}\text{O}$ (l).