3.2 INTERNAL ENERGY + ENERGY TRANSFERS Flashcards
What is the internal energy of a substance?
● The energy stored by the particles
● The sum of the total kinetic and
potential energies that make up the system
How does heating affect the energy of a substance?
● Heating transfers energy to the substance
● It increases the energy of the particles that make up the substance
What two things can heating a substance do?
- Raise its temperature
2. Change the state of the substance
What three factors determine the temperature change of a system?
- Mass of substance being heated 2. Type of material (Specific heat
capacity) - Energy inputted into the system
State the equation used to calculate the temperature change when a substance is heated. Give appropriate units.
● ΔE = m c Δ𝛉
● Energy (J), Mass (kg), Specific Heat
Capacity (J/kg/°C), Temperature (°C)
Define specific heat capacity.
The amount of energy needed to increase the temperature of 1kg of a substance by 1°C.
Describe how the internal energy and temperature of a substance changes when a change of state occurs.
● The internal energy of the substance will be increased or decreased
● The temperature of the substance will
remain constant
Define specific latent heat.
The amount of energy needed to change the state of 1kg of a substance with no change in temperature.
State the equation for the energy required to change state. Give appropriate units.
● Energy to change state = mass x specific latent heat
● Energy (J), Mass (kg), Specific latent heat (J/kg)
What is the specific latent heat of fusion?
The energy required to change 1kg of a substance from solid state to liquid state without a change in temperature.
What is the specific latent heat of vaporisation?
The energy required to change 1kg of a substance from liquid state to gas state (vapour) without a change in temperature.
