Thermal Physics Flashcards
Internal energy of an object
The sum of the random distribution of the kinetic and potential energies of its molecules.
First law of thermodynamics
The change of internal energy of the object = the total energy transfer due to work done and heating.
Solid
The atoms and molecules are held to each other by forces due to the electrical charge of the protons and electrons in the atoms. Molecules vibrate randomly about fixed positions.
Liquid
The moelcules move about at random in contact with each other. The forces between the molecules are not strong enough to hold the molecules in fixed positions.
Gas
The molecules also move about randomly but much further apart on average than in a liquid.
Thermal equilibrium
A state of a system in which all parts are at the same temperature.
Ice point
0 degrees celsius
Steam point
100 degrees celsius
Absolute zero
0 K
Triple point of water
273.16 K
Temperature in celsius
Absolute temperature in kelvins - 273.15
Absolute zero definition
The lowest possible temperature, an object at absolute zero has minimum internal energy.
Specific heat capacity, c, of a substance
The energy needed to raise the temperature of unit mass of the substance by 1 K without change of state.
The unit of specific heat capacity
J kg^-1 K^-1
The energy needed to raise the temperature of a substance of mass, m from T1 to T2
ΔQ = mc (T2 - T1)
