Question EXE.2.SL.TZ0.8

$1.8\times {10}^5=\frac{1}{3}\times 2.0\times v^2$  ✓ 

$v=520$ «m s⁻¹»  ✓ 

Average kinetic energy of the molecules is determined by the temperature only ✓

The mass of a molecule is different for each component gas ✓

From $E_{\text{k}}=\frac{1}{2}m{v}^2$, the same $E_{\text{k}}$ and different mass implies a different average velocity  ✓

ALTERNATIVE 1

The average translational speed increases «because T increases» ✓

From $P=\frac{1}{3}\rho v^2$, the density decreases «to keep $P$ constant»  ✓ 

ALTERNATIVE 2

From the ideal gas law, the volume of the gas increases ✓

Since $\rho =\frac{m}{v}$ and $m$ is constant, the density decreases  ✓