Thermal properties of matter

Class 9 · Physics · 6 questions

Name: ____________________ Date: ____________

What is the freezing point of pure water on the Celsius scale?
- A 0 degrees C
- B 100 degrees C
- C 273 degrees C
- D 32 degrees C
What is 0 degrees C on the Kelvin scale?
- A 0 K
- B 273 K
- C 373 K
- D 100 K
The heat needed to raise 1 kg of a substance by 1 K is its:
- A Thermal expansion
- B Heat flow
- C Specific heat capacity
- D Latent heat
How much heat is needed to raise 2 kg of water by 10 K? (specific heat of water = 4200 J/kg K)
- A 84000 J
- B 8400 J
- C 4200 J
- D 42000 J
Which state of matter expands the most for the same rise in temperature?
- A Liquids
- B All expand equally
- C Solids
- D Gases
The heat absorbed when a liquid changes to gas at constant temperature is called:
- A Latent heat of vaporisation
- B Latent heat of fusion
- C Specific heat
- D Sensible heat

Answer key

1. A, 2. B, 3. C, 4. A, 5. D, 6. A

Pure water freezes at 0 degrees C under normal pressure.
T(K) = T(C) + 273, so 0 degrees C is 273 K.
This is the definition of specific heat capacity.
Q = m c delta T = 2 x 4200 x 10 = 84000 J.
Gases expand much more than liquids, and liquids more than solids.
Changing from liquid to gas at its boiling point uses the latent heat of vaporisation.