When molecules in a gas move more quickly, what is increased as a result?

• A. The atomic number of the gas
• B. The mass of the gas molecules
• C. The number of protons in each molecule
• D. The kinetic energy of the gas

Answer: (D)

Verified step by step guidance

1. Understand that the speed of gas molecules is directly related to their kinetic energy, which is the energy of motion.
2. Recall the formula for the average kinetic energy of a gas molecule: \(\text{KE} = \frac{1}{2} m v^2\), where \(m\) is the mass of the molecule and \(v\) is its velocity.
3. Recognize that if the molecules move more quickly (i.e., \(v\) increases), the kinetic energy \(\text{KE}\) increases because it depends on the square of the velocity.
4. Note that the atomic number, mass of the molecules, and number of protons are intrinsic properties of the gas and do not change when the molecules move faster.
5. Conclude that the correct quantity that increases when gas molecules move more quickly is their kinetic energy.