Understanding Heat Concepts

What factors determine the amount of heat needed to change the temperature of a substance?

• Only the temperature change desired

• The mass, specific heat, and temperature change desired

• Only the specific heat of the substance

• Only the mass of the substance

How much heat is required to raise the temperature of 2 kg of water from 20°C to 50°C?

• 251,160 joules

• 100,000 joules

• 500,000 joules

• 1,000,000 joules

What is the equilibrium temperature when a hot piece of copper is placed in water?

• It is the temperature where the heat lost by copper equals the heat gained by water

• It is the average of the initial temperatures

• It is the initial temperature of the water

• It is always 50°C

What is the role of a calorimeter in heat exchange experiments?

• To increase the heat capacity of the system

• To decrease the temperature of the system

• To add heat to the system

• To prevent heat loss to the environment

What additional heat is required to convert water at 100°C into steam?

• No additional heat is required

• Only the specific heat of water is needed

• The latent heat of vaporization is needed

• The latent heat of fusion is needed

What is the latent heat of vaporization for water?

• 2,260,000 joules per kilogram

• 4,186 joules per kilogram

• 333,000 joules per kilogram

• 1,000,000 joules per kilogram

Why can't you use a single specific heat value to calculate the heat required to convert ice at -40°C to steam at 160°C?

• Because the specific heat of ice is the same as water

• Because the specific heat of steam is the same as ice

• Because the specific heat of water is zero

• Because the specific heat of ice, water, and steam are different

What is the first step in converting ice at -40°C to steam at 160°C?

• Directly heating the ice to 160°C

• Melting the ice into water

• Heating the ice to 0°C

• Boiling the ice into steam

What is the latent heat of fusion for water?

• 1,000,000 joules per kilogram

• 2,260,000 joules per kilogram

• 333,000 joules per kilogram

• 4,186 joules per kilogram

How much heat is required to convert 3 kg of ice at -40°C to steam at 160°C?

• 10,000,000 joules

• 12,000,000 joules

• 5,000,000 joules

• 8,000,000 joules