Which statement describes the Ideal Gas Law?

Which statement describes the Ideal Gas Law?

• A. Describes the behavior of a real gas under high pressure.
• B. Governs the motion of electrons in a metal.
• C. Explains phase changes of water at standard conditions.
• D. Describes the behavior of an ideal gas.

Answer: (D)

The main idea being tested is how the relationship among pressure, volume, temperature, and amount of substance is captured for a gas in an idealized model. The Ideal Gas Law combines these variables in the equation PV = nRT, describing how P, V, n, and T relate for an ideal gas where the particles are pointlike and do not attract or repel each other, and collisions are perfectly elastic. It’s a model that works best for gases at high temperature and low pressure, where real gases resemble this ideal behavior. That’s why describing the behavior of an ideal gas is the correct choice. The other options refer to phenomena outside this model: real gases at high pressure deviate from the ideal due to intermolecular forces and finite molecular size; the motion of electrons in a metal pertains to electronic structure and conduction; and phase changes of water involve transitions between phases, not the gas law.

The main idea being tested is how the relationship among pressure, volume, temperature, and amount of substance is captured for a gas in an idealized model. The Ideal Gas Law combines these variables in the equation PV = nRT, describing how P, V, n, and T relate for an ideal gas where the particles are pointlike and do not attract or repel each other, and collisions are perfectly elastic. It’s a model that works best for gases at high temperature and low pressure, where real gases resemble this ideal behavior. That’s why describing the behavior of an ideal gas is the correct choice. The other options refer to phenomena outside this model: real gases at high pressure deviate from the ideal due to intermolecular forces and finite molecular size; the motion of electrons in a metal pertains to electronic structure and conduction; and phase changes of water involve transitions between phases, not the gas law.