Specific Heat Capacity
This lesson covers:
- What 'internal energy' is
- What 'specific heat capacity' is
- How to use the specific heat capacity equation to calculate a change in internal energy
Internal energy is the total energy stored by the particles making up a substance or system.
Which two stores is it comprised of?
Frictional energy stores
Potential energy stores
Kinetic energy stores
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gas / liquid / solid / particles
Temperature is a measure of the average kinetic energy of the in a substance.
- The particles in a have kinetic energy because they are vibrating.
- The particles in a or gas have kinetic energy because they move around.
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Specific heat capacity is the amount of required to raise the of 1 kg of a substance by 1 °C.
However, it can also be thought of as the amount energy released by a substance as it cools.
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The formula for calculating a change in internal energy is:
(Remember that and both mean temperature, and Δ means change)
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In physics, energy change is measured in and mass is measured in .
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A kettle with 0.05 kg of water was heated from 25 °C, to the boiling temperature of 100 °C.
The specific heat capacity of water is 4,200 J/kg°C
How much heat energy is required?
J
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A material with a higher specific heat capacity requires:
Less energy to change its temperature
More energy to change its temperature
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A beaker of water with a mass of 250g was heated until its internal energy increased by 21 kJ.
If the water's original temperature was 24 °C, what is its final temperature?
(Specific heat capacity of water is 4,200 J/kg°C)
°C
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To heat 20g of aluminium by 1*C requires 18 J of energy. To heat the same amount of gold only requires 2.6 J.
Which element must have higher specific heat capacity?
(You don't have to do any calculations)
Aluminium
Gold
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A lump of gold with a mass of 20g was heated to 53 °C, and then allowed to cool down to 28 °C.
If gold's specific heat capacity is 130 J/kg°C, how much internal energy did it lose in the cooling process?
J
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