Question

Calculate `q,w`, and `DeltaU` for the isothermal reversible expansion of one mole of an ideal gas from an initial pressure of `2.0` bar to a final pressure of `0.2` bar at a constant temperature of `273K`.

Answer 1

For isothermal reversible expansion,
`w =- 2.303nRT log .(P_(1))/(P_(2))`
`=- 2.303 xx 1 xx 8.314 xx 273 log.(2.0)/(0.2)`
`w =- 5227.2J`
At constant temperature, for expansion `DeltaT = 0`.
`:. DeltaU = 0`
Also, `DeltaU = 1 xx C_(V) xx DeltaT = 0` (for `1mol)`
and `DeltaU = q +w rArr q = - w = 52272.2J`