A container is filled with a mixture of helium and oxygen gases. A thermometer in the container indicates that the temperature is 22°C. Which gas molecules have the greater average speed? Group of answer choices

The gas molecule which has the greater average speed is: Helium molecules because they are less massive.

Given the following data:

According to the kinetic-molecular theory, the average speed of gas molecules (particles) is highly dependent on temperature and the molar mass of a gas.

This ultimately implies that, the average speed of gas molecules (particles) is directly proportional to the absolute temperature of an ideal gas and inversely proportional to molar mass of the gas.

At a constant temperature, the higher the molar mass of a gas, the lower would be its average speed and vice-versa.

Hence, helium molecules would have the greater average speed at a constant temperature of 22°C because it is less massive and has a lower molar mass in comparison with oxygen gas.

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Helium

Explanation:

The speed of the molecules in a gas is directly proportional to the temperature of the gas and inversely proportional to molar mass of the gas.

This implies that when the temperature of a sample of gas is increased, the speed of the gas molecules is increased accordingly.

At a given constant temperature, the molar mass of the gas is inversely proportional to its average molecular speed. This means that the greater the molecular mass of the gas the lesser the average speed of its molecules.

Oxygen has a greater molecular mass than helium hence it will have a lesser average molecular speed compared to helium.