If your air conditioner is more than several years old, it may use the chloroflu
ID: 987982 • Letter: I
Question
If your air conditioner is more than several years old, it may use the chlorofluorocarbon CCl2F2as the heat transfer fluid. The normal boiling point of CCl2F2 is 29.8 °C, and the enthalpy of vaporization is 20.1 1 kJ/mol. The gas and the liquid have molar heat capacities of 11 7.2 J/mol K and 72.3 J/mol K, respectively. How much energy is evolved as heat when 20.0 g of CCl2F2 is cooled from + 40 °C to 40 °C? I was told the answer is -4800 and I can't get my answer to match. Please show all the steps.
Explanation / Answer
q released = nccl2f2(gas)*c*DT + n*DHvap + nccl2f2(liquid)*c*DT
= (20/120.91)*117.2*(40+29.8)+(20/120.91)*20.11*10^3+(20/120.91)*72.3*(-29.8+40)
= 4801.6 joule
q released = -4801.6 joule.