## Chemistry and Chemical Reactivity (9th Edition)

a) rms speed is inversely proportional to the molecular weight: $CO_2\lt O_2\lt C_2H_6\lt H_2O$ b) Number of moles of ethane: $n=(256/760×1\ atm)×3.26\ L\div 0.082057\ L.atm/mol.K\div 298\ K$ $n=0.045\ mol$ Stoichiometric proportions: $0.045\ mol×9/2=0.158\ mol\ O_2$ Total number of moles: $0.202\ mol$ Final pressure: $P=0.202\ mol×0.082057×298\ K/3.26\ L$ $P=1.51\ atm=1152\ mmHg$ Partial pressure of oxygen: $1152\ mmHg×7/9=896\ mmHg$