Thermodynamics

Thermodynamics

1. Distribution of molecular speeds

   • Internal energy of a substance is the sum of the molecular, kinetic and potential energy
   • An increase in internal energy can result in an increase in temperature of a change of state

2. Heat Transfer

   • Heat flows from a warm area to a cold one
   • Temperature is the degree of hotness, heat is the amount of energy (J), if temperature and energy flow stay constant then it is called a steady state
   • Conduction, metals are better conductors than non-metals because the heat is carried by the free electrons that can carry the energy freely and quickly around the metal and give it to other electrons and ions
   • Convection, when the fluid is heated it expands, this means that it will become less dense than the colder fluid around it, because of this the warmer fluid will try to float over the cooler fluid
   • Radiation, all 'hot' bodies emit infra-red radiation, it is part of the electromagnetic spectrum, the radiation travels in photons, absorption of these transfers energy into random energy of the matter so the internal energy of the matter goes up as it gets hotter

3. Specific heat capacity

   • amount of energy needed to raise 1kg of a substance by 1k
   • c =itv/m sch

4. Latent heat

   • Latent heat of fusion, when ice melts, the energy needed to melt ice at 0°c
     • energy = mass x specific latent heat of fusion
     • E=m^2
     • L - JKG-1
     • E = I + V = ml
   • Latent heat of vaporization is when water boils, then energy needed to boil water at 100°c to a gas at 100°c
     • Em^2
     • PT =M^2
     • itv = ML