33.71 kj·mol-1.
The enthalpy of evaporation of water at 60℃ ΔvapHm (60℃) = 33.71kj·mol-1.
Enthalpy of evaporation (enthalpyofevaporation) is a metrological term announced in 2015. It refers to the heat absorbed during the process of changing a substance from liquid to gaseous state at the same temperature and under a specified pressure.
What is the theoretical heat of evaporation of water?
P = r H =43.93 kJ·mol ― 1 The volume work done during the evaporation of 1mol of water is W=p V= v RT=1×8.314×10 ― 3 kJ·mol ― 1 ·K ― 1 ×298 K=2.48 kJ·mol ― 1 U= Q―W =43.93 kJ·mol ― 1 ―2.48 kJ·mol ― 1 =41.45 kJ· mol ― 1
100 ℃.
The enthalpy of evaporation of water at ΔvapHm (100℃) = 40.63 kJ/mol.
The molar enthalpy of evaporation of water Δ(vap)Hm(H2O) is a function of the temperature T.
It is necessary to first examine the change in molar enthalpy of evaporation with temtemperature, which can be calculated as follows:
The molar enthalpy (generation) of liquid water can be increased by temperature T close to temperature T0.
Δ(f)Hm(H2O,l)(T)
=Δ(f)Hm(H2O,l)(T0)
+Cpm (H2O,l)*(T-T0).
Where Cpm (H2O, l) is the molar heat capacity (constant pressure) of liquid water (not necessarily a constant, heat capacity can have a higher order temperature term), i.e. T = evaporation temperature, and get water The enthalpy before evaporation at that temperature.