Summary and key terms | B.1 Thermal energy transfers

What is matter classified as based on particle arrangement and intermolecular forces?

Matter is classified as solids, liquids, or gases.

What is internal energy composed of?

Internal energy is the total intermolecular potential energy plus the total random kinetic energy of particles.

How is the density of a substance measured?

Density is measured in kilograms per cubic metre (kg m–3).

What happens to molecules at absolute zero (0 K)?

Molecules have theoretically zero energy, zero pressure, and zero volume.

How do you convert degrees Celsius to Kelvin?

Add 273 to the degrees Celsius temperature.

What does specific heat capacity measure?

Specific heat capacity measures the amount of energy required to increase the temperature of 1 kg of a substance by 1 K.

What is the definition of specific latent heat?

Specific latent heat is the amount of energy required to change the phase of 1 kg of a substance at constant temperature.

What is conduction?

Conduction is the transfer of thermal energy due to collisions between particles.

What factors affect the rate of thermal energy transfer by conduction?

The thermal conductivity of the material, its cross-sectional area and length, and the temperature difference between hot and cold parts.

What is convection?

Convection is the transfer of thermal energy due to the mass movement of particles.

What is thermal radiation?

Thermal radiation is the transfer of energy by electromagnetic waves.

What is a black body?

A black body is a theoretical object that absorbs all energy from all wavelengths of light.

What determines the luminosity of a black body?

Luminosity is directly proportional to the surface area and the absolute temperature raised to the fourth power (T^4).

What does the apparent brightness of a star depend on?

Apparent brightness depends on the star's luminosity and inversely on the square of the distance from the observer.