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Quantifying Heat
Thermal CapacitySpecific Heat CapacityMelting & BoilingCondensation & Solidification
Evidences of Heat Transfer
Change in temperature
Change of state
Change in amount
Change in TemperatureThe amount of heat supplied is directly proportional to the
change in temperature.
E = heat
𝑬∝∆ 𝜽
𝑬=𝒌∆𝜽θ = temperaturek = constant
∆ 𝜽=𝜽 𝒇− 𝜽𝒊
Thermal Capacity
The amount of heat required to change the temperature of
a substance by 1 C°.
Factors affecting Thermal Capacity The amount of substance
MassSymbol: mUnit: kgThe greater the mass, the more heat required
The type of substancePropertySpecific heat capacity
Symbol: cUnits: J/kg-K or J/kg-C°The greater the c, the more heat required
𝑬∝𝒎
𝑬∝𝒄
Specific Heat Capacity
The amount of heat required to change the temperature of a
kilogram of substance by 1 C°.
Tells how difficult it is to change the temperature
of a substance
Specific Heat Capacities of some substances
Water is used as heating fluid in radiators.
Water is in a hot compress
England is green.
Pies make you cry.
Quantifying Heat (with change in Temperature)
Joule meter
𝑬∝∆ 𝜽
𝑬=𝒎𝒄 ∆𝜽
𝑬∝𝒎 𝑬∝𝒄
)
Page 89, SQSample Problems
Change of State
Process when a substance changes from solid to liquid
Melting
At constant temperatureMelting pointSolidification/Fusion
Process when a substance changes from liquid to solid
At constant temperatureFreezing point
Change of State
Process when a substance changes from liquid to gas
Vaporization
At constant temperatureBoiling pointCondensation
Process when a substance changes from gas to liquid
At constant temperatureDew point
Graph
Boiling versus Evaporation
Boiling Evaporation
Occurs at a specific
temperatureOccurs at any temperature
Occurs inside the liquid Occurs at the surface
Change from liquid to gasChange from liquid to gas
Quantifying Heat (with change of state)
Joule meter
𝑬=𝒎𝑳
𝑬∝𝒎 𝑬∝𝑳
Page 89, SQSample Problems
L = Latent HeatUnit: J/kg
Leveling Up
A 500 g piece of aluminium is heated with a 500 W heater for 10 minutes.(a) How much energy will be given to the aluminium in this time?(b) If the temperature of the aluminium was 20°C at the beginning, what will its temperature be after 10 minutes?
Leveling Up
Latent HeatThe amount of heat required
to change the state of a kilogram of a substance.
Latent heat of fusion for liquid to solid and vice versa
Latent heat of vaporization for liquid to gas and vice versa
Latent HeatUsed to break molecular bonds
Changes potential energy
No change in kinetic energy