## Chemistry and Chemical Reactivity (9th Edition)

Number of moles of air: $n=PV/RT$ $n=1.0\ atm×1\ km^3×1×10^{12}\ L/km^3/0.082057\ L.atm/mol.K/(25+273)\ K$ $n=4.09×10^{10}\ mol$ Number of moles of methane: $4.09×10^{10}\ mol_{air}×177.4\ mol_{CH_4}/10^9\ mol_{air}=7255\ mol$ A) Number of molecules: $7255\ mol×6.022×10^{23}\ molecules/mol=4.44×10^{27}\ molecules$ B) From stoichiometry, the number of moles of methane and methylphosphonate are the same: $7255\ mol×95.01\ g/mol=689.3\ kg$