Chapter 9, Problem 9.92PAE

9.98 Hydrogen combines with oxygen in fuel cells according to the thermochemical equation

   ${\text{2H}}_{\text{2}}\left(\text{g}\right)+{\text{O}}_{\text{2}}\left(\text{g}\right)\to {\text{2H}}_{\text{2}}\text{O}\left(\text{g}\right)$

$\Delta \text{H}°$= -571.7 kJ

Suppose that you are working with a firm that is using hydrogen fuel cells to power satellites. The satellite requires $\text{4}.0\times \text{1}{0}^{\text{5}}$ kJ of energy during its useful lifetime to stabilize its orbit. Describe how you would determine the mass of hydrogen you would need in your fuel cells for this particular satellite.