internal energy & energy transfers

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 2 things can heating a substance do?

1. raise its temperature

2. change the state of the substance

what 3 factors determine the temperature change of a system?

1. mass of substance being heated

2. type of material (specific heat capacity)

3. energy inputter into the system

state the equation used to calculate the temperature change when a substance is heated. give units

• heat energy = mass x specific heat capacity x temperature change

• 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 1 kg of a substance by 1°C

Describe how the internal energy and temperature of a substance changes when a change in 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 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 without a change in temperature