- #1

sty2004

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## Homework Statement

The van der Waals’ equation of state for one mole of gas is given by

(P+a/V

^{2})(V-b)=RT

where V is the molar volume at temperature T, and a and b are constants. The internal energy of the gas is given by

E=(3/2)RT-a/V

Initially, one mole of the gas is at a temperature T1 and occupies a volume V1. The gas is allowed to expand adiabatically into a vacuum so that it occupies a total volume V2. What is the final temperature of the gas?

## Homework Equations

## The Attempt at a Solution

I guess the energy of the gas is constant as it is an adiabatic expansion(right?..).

So E

_{1}=E

_{1}and so T

_{2}=T

_{1}+2a/(3R)(1/V

_{2}-1/V

_{1})

Do I need the first equation provided?