# Question #396f4

Helium will have the higher velocity given that both gases are at the same temperature.

#### Explanation:

If both gases are at the same temperature, their kinetic energy (KE) values will be equal to each other.

KE = $\frac{1}{2} m {v}^{2}$

Since the mass of He is 4g/mol and $C {O}_{2}$ is 44g/mol the He atoms must be moving much faster than the $C {O}_{2}$ molecules since their mass is so much lower.

You can calculate how much faster He atoms will move by using Graham's law. Here is a video discussing how to use this law. The sample uses He and ${N}_{2}$, to solve for your question you would just substitute in the $C {O}_{2}$ value instead of nitrogen then re-calculate.

Hope this helps!