## Chemistry and Chemical Reactivity (9th Edition)

a) The first reaction is endothermic with $\Delta H_r=206.2\ kJ/mol$, the second is exothermic with $\Delta H_r=-41.2\ kJ/mol$ b) The number of moles of hydrogen required: $1.5\times10^{13}\ g\div17.03\ g/mol\times3\ mol\ H_3/2\ mol\ NH_3=1.32\times10^{12}\ mol$ By adding the equations: $CH_4+2\ H_2O\rightarrow CO_2+4\ H_2$ Mass of CH4 required: $1.32\times10^{12}\ mol\times 1\ mol\ CH_4/4\ mol\ H_2\times 16.04\ g/mol=5.30\times10^{12}\ g=5.3\ billion\ kg$ Mass of CO2 produced: $1.32\times10^{12}\ mol\times 1\ mol\ CH_4/4\ mol\ H_2\times 44.01\ g/mol=1.45\times10^{13}\ g=14.5\ billion\ kg$