Thermodynamics

Question 1

What are the two equations for change in energy and when do we use them in Thermodynamics?

Answer 1

• ΔE = mcΔθ is used when change in temperature but no change in state
• ΔE = LΔm is used when change in state but no change in temperature

Question 2

What should you do for a thermodynamics question?

Answer 2

• Write an energy sentance
• e.g Energy gained to melt the ice = Energy lost from cooling water
• So LΔm = mcΔθ

Question 3

What is Latent heat of fusion?

Answer 3

• Solid to Liquid
• Liquid to Solid

Question 4

What is latent heat of vapourisation?

Answer 4

• Liquid to Gas
• Gas to Liquid