## Chemistry and Chemical Reactivity (9th Edition)

Ar has a greater molecular weight than $N_2$ so at the same mass, $N_2$ has a bigger number of moles, and since T and V are the same, $N_2$ is in a flask with greater pressure ($P\propto n$). Since $\sqrt{\bar{u^2}}=\sqrt{3RT/M}$, and the temperatures are the same, $N_2$ will have a bigger rms speed because it has a lower molecular weight. a) True b) False c) False d) True, number of collisions with the walls is measured by the pressure.