# Hard problem

1. Apr 17, 2005

### apchemstudent

I know this might be a chemistry question in a way, but they also have Gas Laws problems in a physics textbooks.

I have no idea how to solve this problem. I used the pressure ratios to determine the percent increase in volume. But I'm stuck there. Please help. Thanks.

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2. Apr 17, 2005

### GCT

by avogadro's law the volume percent is equivalent to the mole percentage. In addition the mole percentage is equal to the pressure percentage (by dalton's law of partial pressures). Keep this in mind for the rest of this post.

I got one percent.
$$[100.47-(101.23-.02(101.23))]/100.47$$
equivalent to the new volume percentage

I'm still not quite sure why they gave the molecular weight of gases in the problem, PV=nRT does not depend on mass composition, it is a colligative property.