Thermal Energy

• Internal Energy


  Sum of all kinetic energies and potential energies of all particles randomly distributed
• Specific Heat capacity 


  The amount of energy required to increase temperature of 1Kg of a substance by 1°C without changing state
• Specific Latent Heat


  Amount of energy required to change state of 1Kg of a substance without changing temp.
• If state changes…

  Internal energy changes: potential energy changes, Kinetic energy the same
• When changing state energy

  used to break bonds between molecules. Potential increases, Kinetic the same.
• $Q =$$ml$

  Changing state
• Specific latent heat of fusion is solid to liquid
• Specific latent heat of vaporisation is liquid to gas
• Energy transfer is the same in a closed system
• Absolute zero 


  Lowest possible temperature (-263°K)
• $K=$$°C +$$273$
• 1 mole = 6.02x10^23
• Molar mass 


  mass (g) of 1 mole
• Mr 


  relative molecular mass
• Mass = moles x mr
• Q = m c (change in temp)
• P = E/ t
• number of moles = number of particles / Avagadro‘s constant
• Heat into the system Is positive energy, and the change in internal energy is positive
• work on the system is negative energy, and change in internal energy is positive
• Work by the system is positive energy and change in internal energy is negative
• Kinetic energy doesn’t change when changing state as the energy is used to overcome the electrostatic forces of attraction between particles
• If two substances in contact, total E gained by m1 = Total E lost by m2
• When two substance and one changes state, m1L1 + m1C1(T-T1) = m2C2(T2-T) where T is the final temperature of the colder (T1) and warmer (T2) substances
• To find absolute 0, you cool a gas ( Charles‘ law) and volume at a constant pressure, plotting V against T. extrapolate for 0 K.