What is the Reference State for Finding Specific Enthalpy on a Mollier Diagram?

[Gauss M.D.]

Homework Statement

We have a saturated vapor mixture with relative humidity 80% at a termpature of 30 C. Find the specific enthalpy of the mixture.

Homework Equations

The Attempt at a Solution

I missed a lecture and a session due to illness and have fallen behind. We are allowed to use a Mollier diagram. Been trying various calculations and table lookups for hours now but getting nowhere. Any pointers?

 

[hjelmgart]

Try this site, though it may lack explanations, you do have the math and numbers needed to do it:
http://www.engineeringtoolbox.com/enthalpy-moist-air-d_683.html
(I used it frequently for my Physical Chemistry class)

 

[Chestermiller]

Homework Statement

We have a saturated vapor mixture with relative humidity 80% at a termpature of 30 C. Find the specific enthalpy of the mixture.

Homework Equations

The Attempt at a Solution

I missed a lecture and a session due to illness and have fallen behind. We are allowed to use a Mollier diagram. Been trying various calculations and table lookups for hours now but getting nowhere. Any pointers?

There are several ways of doing what you want. The mixture can't be saturated, because the humidity is not equal to 100%. Saturated means 100% RH.

A second thing you should know is that, to find the specific enthalpy of the mixture, you need to know the reference state at which the enthalpy is taken to be zero. This is usually 0 C and 1 atm for the pure species, but, in some tables it is 25C.

Your Mollier diagram should give you what you want. Can you show us the Mollier diagram you are working with. The diagram should specify the reference state for zero enthalpy.

Chet