Which statements describe the typical assumptions of an ideal gas?

Which statements describe the typical assumptions of an ideal gas?

• A. Inelastic collisions, significant molecular size, and strong intermolecular forces
• B. Fixed energy distribution among molecules
• C. Perfectly elastic collisions, negligible molecular size, and no intermolecular forces
• D. Particles arranged in a lattice with no movement

Answer: (C)

In kinetic theory, an ideal gas is modeled as many tiny point particles moving in random motion, with collisions that are perfectly elastic, negligible molecular size, and no intermolecular forces except during those instantaneous collisions. This combination—elastic collisions, essentially zero particle size relative to the container, and no attractive or repulsive forces between molecules—defines the ideal-gas assumptions and explains why this option is the correct description. The other statements conflict with the model: inelastic collisions would lose energy, finite molecular size means the particles occupy space, and intermolecular forces would affect how pressure and temperature relate to each other; a lattice with no movement describes a solid, not a gas.

In kinetic theory, an ideal gas is modeled as many tiny point particles moving in random motion, with collisions that are perfectly elastic, negligible molecular size, and no intermolecular forces except during those instantaneous collisions. This combination—elastic collisions, essentially zero particle size relative to the container, and no attractive or repulsive forces between molecules—defines the ideal-gas assumptions and explains why this option is the correct description. The other statements conflict with the model: inelastic collisions would lose energy, finite molecular size means the particles occupy space, and intermolecular forces would affect how pressure and temperature relate to each other; a lattice with no movement describes a solid, not a gas.