thermal capacity specific heat capacity melting & boiling condensation & solidification

18
Quantifying Heat Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

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Page 1: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

Quantifying Heat

Thermal CapacitySpecific Heat CapacityMelting & BoilingCondensation & Solidification

Page 2: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

Evidences of Heat Transfer

Change in temperature

Change of state

Change in amount

Page 3: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

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

Page 4: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

Thermal Capacity

The amount of heat required to change the temperature of

a substance by 1 C°.

Page 5: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

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

Page 6: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

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

Page 7: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

Specific Heat Capacities of some substances

Page 8: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

Water is used as heating fluid in radiators.

Water is in a hot compress

England is green.

Pies make you cry.

Page 9: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

Quantifying Heat (with change in Temperature)

Joule meter

𝑬∝∆ 𝜽

𝑬=𝒎𝒄 ∆𝜽

𝑬∝𝒎 𝑬∝𝒄

)

Page 89, SQSample Problems

Page 10: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

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

Page 11: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

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

Page 12: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

Graph

Page 13: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

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

Page 14: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

Quantifying Heat (with change of state)

Joule meter

𝑬=𝒎𝑳

𝑬∝𝒎 𝑬∝𝑳

Page 89, SQSample Problems

L = Latent HeatUnit: J/kg

Page 15: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

Leveling Up

Page 16: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

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

Page 17: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

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

Page 18: Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

Latent HeatUsed to break molecular bonds

Changes potential energy

No change in kinetic energy