At standard pressure, ammonia melts at 195 K and boils at 240 K. If a sample of ammonia at standard pressure is cooled from 200 K down to absolute zero, what physical constants are needed to calculate the change in

enhtalpy?
I) the heat capacity of ammonia(s)
II) the heat capacity of ammonia(`)
III) the heat capacity of ammonia(g)
IV) the enthalpy of fusion of ammonia
V) the enthalpy of vaporization of ammonia

2 answers

You need the heat capacity of liquid NH3 to go from 200 K to 195K, the enthalpy of fusion to freeze the liquid NH3 to solid NH3 @ 195, then you need the heat capacity of solid NH3 to go from 195K to zero K.
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