# Help! Finding molar flow rate of product out of a condenser

1. Oct 15, 2007

Ok. I have attempted this problem several times and went about it a couple of different ways and still cannot get a viable answer!

the problem is:

A gas stream contains 18.0 mole% hexane (C6H14) and the remainder nitrogen. The stream flows to a condenser, where its temperature is reduced and some of the hexane is liquefied. The hexane mole fraction in the gas stream leaving the condenser is 0.0500. Liquid hexane condensate is recovered at a rate of 1.50 L/min.

see attached *.doc file for a diagram relating to the problem!!!

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2. Oct 15, 2007

oh, sorry. The question is: What is the flow rate of the gas stream leaving the condenser in mol/min?

Note: I have always begun by finding the molar flow rate of the condensate.

3. Oct 15, 2007

### Gokul43201

Staff Emeritus
You'll have to make at least one assumption along the way: either you work with constant total flow rate, or with constant total pressure (or something else). With the first assumption, you can write down the ratio of flow rate out to flow rate in from the given data. The second equation is just a mass balance relation. The two equations can be solved for the two unknowns.

4. Oct 15, 2007