Thermal Capacity Specific Heat Capacity Melting & Boiling Condensation & Solidification

Evidences of Heat Transfer Change in temperature Change of state Change in amount

Change in Temperature The amount of heat supplied is directly proportional to the change in temperature. E = heat θ = temperature k = constant

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  Mass  Symbol: m  Unit: kg  The greater the mass, the more heat required  The type of substance  Property  Specific heat capacity  Symbol: c  Units: J/kg-K or J/kg-C °  The greater the c, the more heat required

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 Page 89, SQ Sample Problems

Change of State  Process when a substance changes from solid to liquid Melting  At constant temperature  Melting point Solidification/Fusion  Process when a substance changes from liquid to solid  At constant temperature  Freezing point

Change of State  Process when a substance changes from liquid to gas Vaporization  At constant temperature  Boiling point Condensation  Process when a substance changes from gas to liquid  At constant temperature  Dew point

Graph

Boiling versus Evaporation BoilingBoiling EvaporationEvaporation Occurs at a specific temperature Occurs at any temperature Occurs inside the liquid Occurs at the surface Change from liquid to gas

Quantifying Heat (with change of state) Joule meter Page 89, SQ Sample Problems L = Latent Heat Latent HeatLatent Heat Unit: 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 Heat The 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 Heat Used to break molecular bonds Changes potential energy No change in kinetic energy