# Thermodynamics

posted by
**Becca**
.

The initial state consists of a closed system containing one mole of super-heated liquid water at 115°C and 1 atmosphere pressure. The immediate surroundings are also at 115°C and 1 atmosphere pressure.

The change in state is described as this one mole of super-heated liquid water vaporizing to water vapor at 115°C, as shown by the following reaction at 1 atmosphere pressure.

1 mole, H2O, liquid, 115°C ---> 1 mole, H2O, vapor, 115°C

a) Calculate the Enthalpy change for the system at 115°C.

b) Calculate the Entropy change for this system at 115°C.

c) Assuming that the surroundings behave as a constant temperature reservoir,

calculate the Enthalpy change for the surroundings

d) Assuming that the surroundings behave as a constant temperature reservoir,

calculate the Entropy change for the surroundings

e) Calculate the Entropy change for the universe.

Given the following:

Cp (liquid) = 75.33 J/mole K,

Cp (vapor) = 37.47 J/mole K,

∆H vaporization (100°C) = 40790 J/mole

I really have no idea what to do or where to start. I know I need to break the problem down into steps but I'm not sure exactly how to split it up.