What happens to the particles of a substance when it is heated?

The correct answer is They move faster.

Key Points

• When a substance is heated, its particles gain kinetic energy, causing them to move faster.
• Heating increases the temperature, which directly affects the motion of particles in solids, liquids, and gases.
• In solids, the particles vibrate more vigorously around their fixed positions as the temperature rises.
• In liquids and gases, the particles move faster and spread out, leading to processes like expansion and changes in state (e.g., evaporation).
• This phenomenon is explained by the Kinetic Theory of Matter, which states that particles are in constant motion and their energy depends on temperature.

Additional Information

• Kinetic Energy:
  • The energy possessed by a particle due to its motion.
  • It increases with temperature, causing faster movement of particles.
• Expansion on Heating:
  • Substances generally expand when heated due to increased particle motion.
  • This property is utilized in applications like thermometers.
• Phase Changes:
  • Heating can cause substances to change state, such as solid to liquid (melting) or liquid to gas (evaporation).
  • This occurs because particles move faster and overcome intermolecular forces.
• Kinetic Theory of Matter:
  • A scientific theory explaining the behavior of particles in matter based on their kinetic energy.
  • States that temperature is a measure of the average kinetic energy of particles.
• Brownian Motion:
  • An observable phenomenon in liquids and gases where particles move randomly due to collisions.
  • It becomes more prominent as particles gain energy from heating.