THERMAL PHYSICS
Heat - An amount of energy that flows from one body to another due to temperature difference (in Joules).
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Temperature - Degree of hotness or coldness
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Kelvin
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Celsius
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Fahrenheit
1 cal = 4.186 J
INTERNAL ENERGY - Sum of kinetic and potential energy in the particles present in a body.
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KINETIC ENERGY - Vibration of particles; affected by change in temperature
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POTENTIAL ENERGY - Interaction between different particles (Dipole attraction; intermolecular forces; Van der Waals forces)
EXPANSION reveals internal potential energy.
TEMPERATURE reveals internal kinetic energy (measured by thermometer).
SOLIDS
- Low kinetic energy
- Strong intermolecular forces
- Fixed shape
- Cannot be compressed
LIQUIDS
- Higher kinetic energy than solids
- Weaker intermolecular forces than solids
- Take shape of container
GASES
- High kinetic energy
- Weak intermolecular forces
- No fixed shape
- Can be compressed
ENDOTHERMIC PROCESSES
MELTING - Solid to Liquid
VAPORIZATION - Liquid to Gas
SUBLIMATION - Solid to Gas
EXOTHERMIC PROCESSES
FREEZING - Liquid to Solid
CONDENSATION - Gas to Liquid
DEPOSITION - Gas to Solid
Boiling - The temperature at which liquid starts to convert into vapor (gaseous state) at the temperature at which the internal pressure of the liquid molecules becomes equal to the external pressure of the atmosphere, and molecules start escaping from the surface.
LATENT HEAT OF FUSION - Amount of heat energy required by a substance to convert 1 kg from solid to liquid at constant temperature.
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LATENT HEAT OF VAPORIZATION - Amount of heat energy required by a substance to convert 1 kg from liquid to gas at constant temperature.
ABSOLUTE TEMPERATURE (0 K) - All motion ceases to exist. Indicates Charles's Law (V1/T1 = V2/T2) .
Heat Capacity - The amount of heat that is required to raise the temperature of an object through 1 C/ 1 K.
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Specific Heat Capacity - The amount of heat that is required to raise the temperature of a 1 kg object through 1 C/ 1 K.
LAW OF HEAT EXCHANGE
"The amount of heat lost by a hot body is the amount of heat gained by a cold body in a closed system."
MODES OF HEAT TRANSFER
1. CONDUCTION - Between solids; atoms vibrate about their fixed positions
2. CONVECTION - Between liquids and gases; movement of particles
3. RADIATION - In the form of waves/photons
