thermal capacity specific heat capacity melting & boiling condensation & solidification

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