State changes, latent heat

What are the three states of matter?

Solid, liquid, gas.

What is meant by a change of state?

A physical change where a substance becomes a solid, liquid or gas without changing its chemical identity.

What happens to mass during a change of state?

Mass is conserved.

What happens to temperature during melting?

Temperature stays constant while the solid turns into a liquid.

What happens to temperature during boiling?

Temperature stays constant while the liquid turns into a gas.

What is melting?

Solid → liquid.

What is freezing?

Liquid → solid.

What is boiling?

Liquid → gas throughout the liquid.

What is evaporation?

Liquid → gas at the surface only.

What is condensation?

Gas → liquid.

What is sublimation?

Solid → gas.

What is deposition?

Gas → solid.

What is internal energy?

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

What happens to internal energy when a substance is heated?

Internal energy increases because particles move faster and/or move further apart.

Why does temperature stay constant during a change of state?

Energy is used to break or form bonds instead of increasing kinetic energy.

What is specific latent heat?

The energy needed to change the state of 1 kg of a substance without changing temperature.

State the equation for specific latent heat.

Energy = mass × specific latent heat.

What is specific latent heat of fusion?

Energy needed to change 1 kg between solid ↔ liquid.

What is specific latent heat of vaporisation?

Energy needed to change 1 kg between liquid ↔ gas.

Why does steam at 100°C contain more energy than water at 100°C?

Steam has gained latent heat of vaporisation.