Question

If equal masses of O2(g) and HBr(g) are in separate containers of equal volume and temperature, which one of these statements is true? The pressure in the O2 container is greater than that in the HBr container. The average velocity of the O2 molecules is less than that of the HBr molecules. The average kinetic energy of HBr molecules is greater than that of O2 molecules. The pressures of both gases are the same. There are more HBr molecules than Oz molecules.

Answer 1

The average velocity of the HBr molecules is greater than that of the O2 molecules. The average kinetic energy of the HBr molecules is greater than that of the O2 molecules. The pressures of both gases are the same.

Step-by-step explanation:

In this scenario, the statements that are true are:

1. The average velocity of the O2 molecules is less than that of the HBr molecules.
2. The average kinetic energy of HBr molecules is greater than that of O2 molecules.
3. The pressures of both gases are the same.

Equal masses of gases at the same temperature have the same average kinetic energy. However, the average velocity of the molecules is inversely proportional to the square root of their mass. Since the molecular mass of HBr is greater than that of O2, the average velocity of HBr molecules is less than that of O2 molecules. The average kinetic energy of the molecules is directly proportional to the square of their velocity. Therefore, since the average velocity of HBr molecules is less, their average kinetic energy is greater than that of O2 molecules. Finally, since the masses and temperatures are equal, the pressures of both gases are the same.

Answer 2

The pressure in containers with equal masses of O2(g) and HBr(g), if both have the same volume and temperature, will be the same due to the ideal gas law. However, O2 molecules will have a lower average velocity compared to HBr molecules because of O2's lower molar mass relative to HBr.

Step-by-step explanation:

If equal masses of O2(g) and HBr(g) are in separate containers of equal volume and temperature, the statement that is true is: The pressures of both gases are the same. This is because, according to the ideal gas law and the kinetic molecular theory, at the same temperature and volume, equal masses of ideal gases will exert the same pressure regardless of their chemical identity. This is under the assumption that both gases behave ideally and the number of moles is the same for both gases. Additionally, gases with lighter molar masses will have higher average velocities, so O2 molecules will have a lower average velocity than HBr molecules because oxygen has a lower molar mass compared to hydrogen bromide.