Internal Energy

• What is meant by internal energy?

  The kinetic and potential energy stored in a system by particles
• What happens when a material changes state?

  Internal energy changes during the process
• How do particles in a solid behave?

  They vibrate in a fixed position
• How do particles in a liquid behave?

  They can move around each other
• How do particles in a gas behave?

  They move extremely rapidly
• What type of energy do all particles possess?

  Both kinetic and potential energy
• What are intermolecular forces?

  Forces between particles that give potential energy
• What does internal energy include?

  Total kinetic and potential energy of particles
• Why is internal energy important during changes of state?

  It determines the state of the material
• What is the process called when a solid turns into a liquid?

  Melting
• What happens when we heat a liquid?

  It increases internal energy and may boil
• What is the term for when a liquid turns into a gas?

  Boiling
• What is condensation?

  Gas turning back into a liquid
• What is freezing?

  Liquid turning into a solid
• What is sublimation?

  Solid turning directly into a gas
• What happens to mass during changes of state?

  Mass is always conserved
• Are changes of state physical or chemical changes?

  They are physical changes
• What happens when ice melts to water and refreezes?

  It recovers its original properties
• What is evaporation?

  Liquid turning to gas at the surface
• Which particles can turn into gas during evaporation?

  Only surface particles
• What is the relationship between internal energy and temperature during state changes?

  Internal energy changes with temperature
• How do changes of state differ from chemical changes?

  They are reversible and retain properties
• What happens to the internal energy when a gas is cooled?

  It decreases internal energy
• What is the significance of the intermolecular forces in potential energy?

  They contribute to the potential energy of particles
• What is the state of carbon dioxide at room temperature and pressure?

  It can sublimate directly to gas
• What is the role of temperature in the melting process?

  Temperature increase leads to melting
• How does the process of boiling differ from melting?

  Boiling involves liquid turning to gas
• What happens to the kinetic energy of particles during freezing?

  Kinetic energy decreases significantly
• How does cooling affect the state of a gas?

  It can turn into a liquid through condensation
• What is the definition of boiling?

  Liquid turning into gas at boiling point
• What is the significance of the surface particles during evaporation?

  They have enough energy to become gas
• How do physical changes differ from chemical changes in terms of reversibility?

  Physical changes are reversible, chemical are not
• What happens to the properties of a material when it undergoes a physical change?

  It retains its original properties
• What is the relationship between internal energy and state changes?

  Internal energy changes drive state changes
• What is the process of a solid turning into a gas called?

  Sublimation
• What is the effect of increasing temperature on a solid?

  It increases the internal energy of the solid
• How does the concept of internal energy relate to the states of matter?

  It explains the energy dynamics in each state
• What happens to the internal energy of a liquid when it freezes?

  It decreases as it turns into solid
• What is the significance of learning about internal energy and changes of state?

  It helps understand physical processes in materials