Direction of thermal energy transfer between 2 objects is determined by temperature (temp is proportional to avg KE of particles in the substance) when bodies are in thermal contact. After enough contact thermal equilibrium is reached (temp of 2 bodies is the same).
Tk = Tc + 273.15
Heat = energy transfered from one body and into another as a result of a difference in temperature during a thermal interaction ... Hot to Cold.
Internal Energy = total KE of the molecules of a substance, plus any PE associated with forces between the molecules.
KE is the movement of particles and PE is associated with the binding forces of the particles ... the tighter the bond the lower the PE.
Physical differences of Solid, Liquid and Gas
Temperature does not change during phase change. Energy given to molecules does not change the KE (temp) therefore it changes the PE (bonds). All energy is used to break intermolecular bonds.
Difference between evaporation and boiling.
Specific latent heat of fusion, Lf : Thermal energy required to melt a unit of mass of material at its melting point. Q = mLf
Specific latent heat of vaporization, Lv : Thermal energy required to vaporize a unit of mass of material at its boiling point. Q = mLv