Consider a sample containing 1.1 moles of liquid water at its boiling point. Sufficient energy is input into the system to vaporize all the water, and then raise
the temperature of the steam to 455.15K. The pressure is held constant at 1 bar, the molar enthalpy of vaporization of water is 40650(J)/(m)ol, and
C_(P,m,steam) is a constant 33.58(J)/(m)olK.
The overall enthalpy change of this process is the sum of the enthalpy change of vaporizing the gas and the enthalpy change of heating the steam.
What is the total enthalpy change for this process?
Of course, we know that when water vaporizes, its volume increases substantially. This expansion means that the water does quite a bit of work during this
process! The volume of liquid water is 1.89 imes 10^(-5)m^(3)mol-1. The molar volume of steam at 373.15K is 0.0303m^(3)mol^(-1). The molar volume of steam at
455.15K is 0.037843m^(3)mol^(-1).
Add up the work done during the inital irreversible expansion of the water as it vaporizes at its boiling point and the subsequent work done as the steam
irreversibly expands. What is the total work during the overall process?
With these numbers, and the knowledge that the pressure is constant, calculate Delta U for the system during this process.
Consider a sample containing 1.1 moles of liquid water at its boiling point. Sufficient energy is input into the system to vaporize all the water, and then raise the temperature of the steam to 455.15 K.The pressure is held constant at 1 bar, the molar enthalpy of vaporization of water is 40650 J/mol, and
The overall enthalpy change of this process is the sum of the enthalpy change of vaporizing the gas and the enthalpy change of heating the steam
What is the total enthalpy change for this process?
47794.96
Of course, we know that when water vaporizes, its volume increases substantially. This expansion means that the water does quite a bit of work during this
455.15 K is 0.037843 m3mol-1.
Add up the work done during the inital irreversible expansion of the water as it vaporizes at its boiling point and the subsequent work done as the steam irreversibly expands.What is the total work during the overall process?
-3094
With these numbers, and the knowledge that the pressure is constant, calculate U for the system during this process.
19810
Units