## Z ni dyi

Explain why direct division of (1) by Zni does not yield (3).

7.11 1 mole of pure A at 400 K is mixed with 3 moles of an A-B solution with 33% B at

600 K. Assume that mixing is adiabatic and that A-B solutions follow Regular solution theory with Q = +30 kJ/mole. The heat capacities of pure components A and B are 30 and 50 J/mole-K, respectively.

(a) What is the temperature of the final solution?

(b) What is the entropy change in the process?

7.12 The activity coefficient of component A of an A-B binary solution is given by:

where C and D are constants.

What is the activity coefficient of component B?

Note: the A-B mixture does not follow regular solution theory.

7.13 The activity coefficient of component A of an A-B solution is given by:

where E and F are constants. Student #l claims that the equation for lnyB can be obtained simply by interchanging the subscripts A and B in the equation for lnyA,. Student #2 says that this is wrong, and she can prove it. Show the proof that student #2 has in mind.

7.14 Calculate the entropy change when one mole of pure A is added to 4 moles of an equimolar A-B solution at the same temperature. Assume ideal mixing.

7.15 Give two reasons why the following is not an acceptable formula for describing the activity coefficient of component A in a binary A-B mixture.

## Getting Started With Solar

Do we really want the one thing that gives us its resources unconditionally to suffer even more than it is suffering now? Nature, is a part of our being from the earliest human days. We respect Nature and it gives us its bounty, but in the recent past greedy money hungry corporations have made us all so destructive, so wasteful.

## Post a comment