Define specific heat capacity .

The specific heat capacity of a substance is the thermal energy required to raise the temperature of 1 kg of the substance by 1 °C.

What are the units of specific heat capacity?

J kg -1 K -1 (equivalently J kg -1 °C -1 ).

How does a substance with a low specific heat capacity behave when heated or cooled, compared with one with a high specific heat capacity?

A substance with a low specific heat capacity heats up and cools down quickly ; one with a high specific heat capacity heats up and cools down slowly .

True or False? The specific heat capacity of a substance depends on the mass of the sample being heated.

False. Specific heat capacity is a property of the material , defined per kilogram, so it does not depend on the mass of the particular sample.

Define specific latent heat .

The specific latent heat of a substance is the thermal energy required to change the state of 1 kg of the substance without any change in temperature.

Name the five changes of state a substance can undergo.

Melting (solid to liquid) Evaporation/vaporisation/boiling (liquid to gas) Sublimation (solid to gas) Freezing (liquid to solid) Condensation (gas to liquid)

What is the difference between latent heat and specific latent heat?

Latent heat is the energy required to change a material's state; specific latent heat is the energy required to change the state of 1 kg of the material.

During a change of state, the temperature of a substance remains .......... .

During a change of state, the temperature of a substance remains constant (unchanged).

Why does vaporising a liquid require significantly more energy than melting the same mass of solid?

Melting only increases the molecular separation enough for molecules to flow past each other, whereas vaporising must completely separate the molecules , overcoming all the intermolecular forces of attraction between them.

True or False? During melting, the intermolecular forces between molecules are completely overcome, in the same way as during boiling.

False. Melting only increases molecular separation until molecules can flow over each other; it is boiling/vaporisation that completely overcomes the intermolecular forces of attraction.

A LevelPhysicsCambridge (CIE)Flashcards14. TemperatureSpecific Heat Capacity & Specific Latent Heat

Specific Heat Capacity & Specific Latent Heat (Cambridge (CIE) A Level Physics): Flashcards

Exam code: 9702

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Define specific heat capacity.

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Cards in this collection (12)

Define specific heat capacity.
The specific heat capacity of a substance is the thermal energy required to raise the temperature of 1 kg of the substance by 1 °C.
State the equation for the thermal energy ΔQ needed to change the temperature of a mass m by Δθ.
$Δ Q = m c Δ θ$
where c is the specific heat capacity of the substance.
What are the units of specific heat capacity?
J kg^-1 K^-1 (equivalently J kg^-1 °C^-1).
How does a substance with a low specific heat capacity behave when heated or cooled, compared with one with a high specific heat capacity?
A substance with a low specific heat capacity heats up and cools down quickly; one with a high specific heat capacity heats up and cools down slowly.
True or False?
The specific heat capacity of a substance depends on the mass of the sample being heated.
False.
Specific heat capacity is a property of the material, defined per kilogram, so it does not depend on the mass of the particular sample.
Define specific latent heat.
The specific latent heat of a substance is the thermal energy required to change the state of 1 kg of the substance without any change in temperature.
Name the five changes of state a substance can undergo.
- Melting (solid to liquid)
- Evaporation/vaporisation/boiling (liquid to gas)
- Sublimation (solid to gas)
- Freezing (liquid to solid)
- Condensation (gas to liquid)
What is the difference between latent heat and specific latent heat?
Latent heat is the energy required to change a material's state; specific latent heat is the energy required to change the state of 1 kg of the material.
State the equation for the thermal energy Q required to change the state of a mass m with latent heat L.
$Q = L m$
During a change of state, the temperature of a substance remains ...........
During a change of state, the temperature of a substance remains constant (unchanged).
Why does vaporising a liquid require significantly more energy than melting the same mass of solid?
Melting only increases the molecular separation enough for molecules to flow past each other, whereas vaporising must completely separate the molecules, overcoming all the intermolecular forces of attraction between them.
True or False?
During melting, the intermolecular forces between molecules are completely overcome, in the same way as during boiling.
False.
Melting only increases molecular separation until molecules can flow over each other; it is boiling/vaporisation that completely overcomes the intermolecular forces of attraction.

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