A liter container of CO₂ and a liter container of H₂ are both at 25°C and 1 atm pressure. Which of the following statements about these gas samples is true? A)The CO₂ and H₂ molecules have the same average velocity. B)There are more H₂ molecules than CO₂ molecules. C)The average kinetic energy of the CO₂ molecules is greater than that of the H₂ molecules. D)The CO₂ molecules on average are moving more slowly than the H₂ molecules. E)The masses of the two gas samples are equal.

Question

Quizplus · Accepted Answer

At the same temperature, the average kinetic energy of molecules in different gases is the same. However, because kinetic energy is also a function of mass and velocity (KE = 1/2 mv^2), molecules with greater mass (like CO₂, which is a placeholder for a heavier molecule) will have a lower average velocity than lighter molecules (like H₂, representing a lighter molecule).

A Liter Container of CO2 and a Liter Container of H2

A Liter Container of CO₂ and a Liter Container of H₂