Heating matter

• What is the definition of density?

  The mass per unit volume of a material
• What is the equation for density and its units?


  Density (kg/m³) = Mass (kg) / Volume (m³)
• What is meant by a state of matter?

  A form in which matter can exist, based on the particle arrangement in a substance.
• What are the different states of matter in order from least to most dense?

  Least dense: Gas, Liquid, Most dense: Solid
• How does kinetic theory explain the structure of liquids?

  The particles have some kinetic energy and can move around in random directions at very slow speeds.
• How do particles move in a solid?

  The particles vibrate around a fixed position as they do not have enough kinetic energy to move freely.
• Describe the structure of particles in a gas.

  Particles in a gas have almost no forces between them, allowing them to move freely at high speeds in random directions.
• What is always conserved when a substance undergoes a change of state?

  Mass
• How does a change of state differ from a chemical change?

  In a change of state, the material can return to having its previous properties if the change is reversed.
• What is the internal energy of a substance?


  The energy stored by the particles, which is the sum of the total kinetic and potential energies that make up the system.
• What two things can heating a substance do?

  1. Raise its temperature 2. Change the state of the substance
• What three factors determine the temperature change of a substance?

  1. Mass of substance being heated 2. Type of material (Specific heat capacity) 3. Energy inputted into the system
• What is sublimation?


  When a solid turns directly into a gas.
• What is the difference between physical changes and chemical changes in substances?

  Physical changes can be reversed, while chemical changes cannot be easily reversed.
• How does heating cause a substance to change state?

  Heating matter gives particles more potential energy, which is used to break the bonds of attraction, leading to a change of state.
• Why does heating increase the temperature of a substance?

  It increases the amount of thermal energy in that substance, giving the particles more kinetic energy, meaning they move faster and their temperature increases.
• What are the units for the energy change equation?

  Energy (J), Mass (kg), Specific Heat Capacity (J/kg/°C), Temperature (°C)
• What is the equation used to calculate the energy change when a substance is heated?


  ΔE = m c Δ𝛉
• Define specific heat capacity.

  The amount of energy needed to increase the temperature of 1kg of a substance by 1°C.
• Define specific latent heat.

  The amount of energy needed to change the state of 1kg of a substance with no change in temperature.
• What is the equation for the energy required to change state?

  Energy (J) = Mass (kg) x Specific latent heat (J/kg)
• What is the simplified equation for the energy required to change state?

  E = mL