Order of thermal expansion across states of matter

Steps:

• Thermal expansion increases with temperature due to increased particle motion.
• Solids expand least because of strong, fixed lattice structures limiting movement.
• Liquids expand more than solids as weaker forces allow greater volume increase.
• Gases expand most with negligible forces, leading to proportional volume rise per temperature change.

Why C is correct:

• The coefficient of volume expansion (γ) follows γ_gas > γ_liquid > γ_solid, reflecting decreasing intermolecular forces from gas to solid.

Why the others are wrong:

• A: Liquids expand due to increased kinetic energy overcoming cohesive forces.
• B: Identical to C but includes unnecessary "but"; core statement matches expansion order.
• D: Liquids expand more than solids, not the same, due to higher molecular freedom.

Final answer: C