Internal energy and change of state

What is internal energy?

The total energy of all the particles in a substance, including kinetic and potential energy.

How is internal energy affected by heating a substance?

Heating increases the internal energy by increasing the kinetic energy of the particles.

What are the main types of energy in internal energy?

Kinetic energy (due to motion) and potential energy (due to particle interactions).

What happens to the temperature of a substance during a change of state?

The temperature remains constant.

Why doesn’t the temperature change during a change of state?

Energy is used to break or form bonds, not to increase kinetic energy.

What is a physical change?

A change in state or form that does not alter the chemical composition of a substance.

What happens to the internal energy when a substance freezes?

Internal energy decreases as particles lose potential energy.

How do particles behave in a gas compared to a solid?

Gas particles move freely and randomly, while solid particles vibrate in fixed positions.

What are the processes called when a substance changes from solid to liquid and liquid to gas?

Melting and evaporation/boiling, respectively.

What is the reverse process of condensation?

Evaporation or boiling.

What is sublimation?

The direct change of state from solid to gas without becoming a liquid.

How does pressure affect the boiling point of a liquid?

Higher pressure increases the boiling point.

What is required for a change of state to occur?

Energy transfer, either absorbed or released.

What type of change is a change of state: chemical or physical?

Physical.

How does internal energy differ from temperature?

Internal energy includes both kinetic and potential energy, while temperature only measures average kinetic energy.