Chapter 11 - Thermal Properties of Matter Flashcards
Define Heat Capacity
The amount of thermal requires to raise the temperature of a substance by 1 kelvin/ 1 degree celsius
Heat capacity depends on Mass and ______ ?
Type of material
Formula for heat capacity
Heat energy = Heat Capacity x Temperature Change
S.I Unit for heat capacity
J/ Degree Celsius or Kelvin
S.I Unit for Heat ENERGY
Joules (J)
Why can changes in temperature can be given in either Kelvin or Degree Celsius?
When we talk about the change in temperature, the unit is not important, rather, the Value is the most important
Heat energy absorbed by a body
=
_____ in the ______ energy of the molecules
=
_____ _____ due to movement of the molecules
+
_____ _____ due to the intermolecular forces
Increase in the internal energy
Kinetic Energy
Potential Energy
A rise in temperature will take place if ?
ONLY the average kinetic energy of the molecule increase
A CHANGE of state will occur if ?
ONLY the potential energy of the molecules changes
Potential energy of the molecules is depend on which 2 condition?
Intermolecular forces
Space between intermolecular forces
Define SPECIFIC heat capacity
The amount of thermal energy requires to raise the temperature of a unit mass of a substance by 1 Kelvin / 1 Degree Celsius
S.I. Unit of Specific heat capacity
J/kg Kelvin or Degree Celsius
Formula for specific heat capacity
Heat capacity = MASS x Specific heat capacity
If Iron has a specific heat capacity of 460J/ kg Kelvin, what does it mean?
It means that 460 J of HEAT energy is required to raise the temperature of 1 kg of iron by 1 Kelvin
Formula linking Heat ENERGY and SPECIFIC heat capacity
Heat energy = Mass x Specific Heat Capacity x Temperature Change
What is the law of conservation of energy
Thermal energy lost = Thermal energy gained
Formula of ENERGY
Energy = Power x Time
Formula linking Power and Specific Heat capacity
Usually use in Qn that consist of a heater and a substance to find out the Specific Heat Capacity
Power x Time = Mass x Specific Heat Capacity x Temperature Change
Explain how a sea breeze occur?
Due the land have a much smaller heat capacity than the water in the sea, the land heat up faster, causing a difference in temperature between the land and the sea. Due to convection, which hot air will rise up and cold air will rush in to replace the hot air, the sea breeze then occur as the movement of cold air. (Wind = movement of air)
During the change of state, what happen to the temperature?
Remain constant
Melting and Freezing only occur at a DEFINITE temperature provided that ?
The substance is pure
Why during the change of state, the temperature of the substance is unchanged/
ALL thermal energy absorbed is used to BREAK the strong BONDS between particles.
The particles can MOVE OUT of their FIXED position
Hence they are further apart from one another
Thus the change of state occurs
Only the total INTERNAL POTENTIAL Energy is increased, not the kinetic energy
Define latent heat of fusion
The amount of thermal energy required to change a substance from solid state to liquid state, WITHOUT a change in temperature
S.I Unit for Latent heat of fusion/vaporisation
Joules (J)