Understanding Heat: Capacity and Latent Heat

What is the formula for calculating specific heat capacity?

If 500 J of heat is added to 2 kg of a substance, causing its temperature to increase by 5°C, what is the specific heat capacity of the substance?

• 25 J/kg°C

• 50 J/kg°C

• 100 J/kg°C

• 200 J/kg°C

Which of the following best describes latent heat of fusion?

• The heat required to change 1 kg of a substance from solid to liquid without changing its temperature.

• The heat required to change 1 kg of a substance from liquid to gas without changing its temperature.

• The heat required to raise the temperature of 1 kg of a substance by 1°C.

• The heat required to change 1 kg of a substance from gas to liquid without changing its temperature.

What is the latent heat of fusion of ice?

• 334 J/kg

• 334 kJ/kg

• 2260 J/kg

• 2260 kJ/kg

Which of the following best describes latent heat of vaporisation?

• The heat required to change 1 kg of a substance from solid to liquid without changing its temperature.

• The heat required to change 1 kg of a substance from liquid to gas without changing its temperature.

• The heat required to raise the temperature of 1 kg of a substance by 1°C.

• The heat required to change 1 kg of a substance from gas to liquid without changing its temperature.

What is the latent heat of vaporisation of water?

• 334 J/kg

• 334 kJ/kg

• 2260 J/kg

• 2260 kJ/kg

How much heat is required to melt 2 kg of ice at 0°C? (Latent heat of fusion of ice = 334 kJ/kg)

• 668 J

• 668 kJ

• 1336 J

• 1336 kJ

How much heat is required to vaporise 1.5 kg of water at 100°C? (Latent heat of vaporisation of water = 2260 kJ/kg)

• 3390 J

• 3390 kJ

• 4520 J

• 4520 kJ

Which of the following is an application of latent heat in everyday life?

• Boiling water to cook food

• Melting ice to cool drinks

• Both A and B

• None of the above

Why does sweating help cool the body?

• Because the sweat absorbs heat from the body and evaporates, taking the heat away.

• Because the sweat releases heat to the body and evaporates, taking the heat away.

• Because the sweat absorbs heat from the body and condenses, taking the heat away.

• Because the sweat releases heat to the body and condenses, taking the heat away.