(3) Internal Energy and Energy Transfers

Question 1

What is internal energy?

Answer 1

Internal energy is the total kinetic and potential energy of all the particles (atoms and molecules) that make up a system

Question 2

How does heating affect the energy of a substance?

Answer 2

Heating changes the energy stored within the system by increasing the energy of the particles that make up the system.

Question 3

What 2 things could heating a substance do?

Answer 3

1. Raise its temperature
2. Change the state of the substance

Question 4

Equation for specific heat capacity

Answer 4

Energy= mass x specific heat capacity x temperature change
(∆E=MxCx∆θ)
Energy= Joules Mass= kg SHC= J/kg/°C Temperature= °C

Question 5

Define specific heat capacity

Answer 5

The amount of energy needed to raise the temperature of 1kg of a substance by 1°C

Question 6

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

Answer 6

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

Question 7

Define specific latent heat

Answer 7

Specific latent heat of a substance is the amount of energy needed to change the state of 1kg of the substance at a constant temperature

Question 8

Equation for specific latent heat

Answer 8

Energy for a change of state = mass x latent heat
(E=mxl)
Energy= Joules Mass=kg Specific latent heat= J/kg

Question 9

What is specific latent heat of fusion?

Answer 9

Specific latent heat of fusion is the energy required to change 1kg of a substance from solid to liquid or liquid to solid

Question 10

What is specific latent heat if vaporisation?

Answer 10

Specific latent heat of fusion is the energy required to change 1kg of a substance from liquid to gas or gas to liquid