Internal energy is the sum of randomly distributed kinetic energies and potential energies of the particles in a body
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When is the internal energy in a system increased? Name an example.
It is increased when energy is transferred to it by heating or when work is done on it (and vice versa). For example, the qualitative treatment of the first law of thermodynamics
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State the first law of thermodynamics
The change in internal energy, dU of a system is equal to the heat dQ added to the system minus the work done dW by the system.
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What happens to the potential energy and kinetic energy when a substance is changing state?
1. Potential energies - they change 2. Kinetic energies - they remain the same
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What is the sum of kinetic energy and potential energy?
Internal energy
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What are the different states of matter?
Solids, liquids and gases
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Properties of a solid.
low internal energy, molecules are closely packed to each other, regular pattern, vibrates on the spot. Cannot flow or be compressed/ squashed.
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Properties of a liquid.
molecules close together, have a random arrangements, move around each other. They can flow and takes the shape of their container and cannot by compressed/ squashed.
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Properties of a qas
highest internal energy, molecules are far apart, have a random arrangement, move quickly in all directions. Can flow and can be compressed/ squashed.
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Define the specific heat capacity of a material.
The specific heat capacity of a material is the amount of energy needed to change the temperature of a 1kg mass of the material by 1 degree Celsius.
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Which equation uses the specific heat capacity of a material?
Q - m*c*dT
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Define the specific latent heat of fusion
energy required to change the state of unit mass of the substance from solid to liquid without changing the temperature of the substance.
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Define the specific latent heat of vaporisation
energy required to change the state of unit mass of the substance from liquid to vapour without changing the temperature of the substance
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Which equation uses the specific latent heat of a material?
Q = m*l
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What assumptions are considered when looking at l and c?
1. No heat lost into the surroundings 2. there is no change in temperature 3. all the heat is transferred into the material
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Other cards in this set
Card 2
Front
It is increased when energy is transferred to it by heating or when work is done on it (and vice versa). For example, the qualitative treatment of the first law of thermodynamics
Back
When is the internal energy in a system increased? Name an example.
Card 3
Front
The change in internal energy, dU of a system is equal to the heat dQ added to the system minus the work done dW by the system.
Back
Card 4
Front
1. Potential energies - they change 2. Kinetic energies - they remain the same
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