Question

Which sample of oxygen gas contains molecules with the fastest average speed?

Answer 1

Answer:

A. 1.73 x 10^5 J

Explanation:

The internal energy of a gas is related to the average speed of the molecules of the gas. In fact:

- The internal energy, U, is directly proportional to the temperature of the gas, T, according to

$U=\frac{3}{2}nRT$

- The temperature of the gas, T, is proportional to the square of the average speed of the molecules, v, according to

$\frac{3}{2}kT=\frac{1}{2}mv^2$

where both terms represent the average kinetic energy of the molecules.

- Therefore, we can conclude that the higher the internal energy, the faster the average speed of the molecules: among the choices given, the sample with highest internal energy is sample A.