T3 internal energy and energy transfers

Question 1

what is the internal energy of a substance

Answer 1

• energy stored by the particles

- sum of the total kinetic and potential energies that make up the system

Question 2

how does heating affect the energy of a substance

Answer 2

• heating transfers energy to the substance

- increases the energy of the particles that make up the substance

Question 3

what 2 things can heating a substance do

Answer 3

1. raise its temperature

2. change the state of the substance

Question 4

what 3 factors determine the temperature change of a system

Answer 4

1. mass of substance being heated
2. type of material (SHC)
3. energy inputted into the system

Question 5

equation used to calculate the temperature change when a substance is heated

Answer 5

• ΔE = m c Δ𝛉
• Energy (J), Mass (kg), Specific Heat
  Capacity (J/kg/°C), Temperature (°C)

Question 6

define specific heat capacity

Answer 6

amount of energy needed to increase the temperature of 1kg of a substance by 1C

Question 7

describe how the internal energy and temperature of a substance changes when a change of state occurs

Answer 7

• internal energy of the substance will be increased or decreased
• temperature of the substance will remain constant

Question 8

define specific latent heat

Answer 8

amount of energy needed to change the state of 1kg of a substance with no change in temperature

Question 9

state the equation for the energy required to change state

Answer 9

• energy to change state = mass x slh

energy (J), mass (kg), specific latent heat (J/kg)

Question 10

what is the specific latent heat of fusion

Answer 10

energy required to change 1kg of a substance from solid state to liquid state without a change in temperature

Question 11

what is the specific latent heat of vaporisation

Answer 11

energy required to change 1kg of a substance from liquid state to gas state (vapour) without a change in temperature