## Chemistry and Chemical Reactivity (9th Edition)

a) $d=PM/RT$ $M=5.60\ g/L×0.082× 291.2\ K/0.971\ atm$ $M=137.81\ g/mol$ Which is closest to $P_2F_4$'s molecular weight. b) $0.050\ mol/min/0.028\ mol/min=\sqrt{M/44.0\ g/mol}$ $M=140.31\ g/mol$ Which is again closest to $P_2F_4$'s molecular weight.