One mole of a gas expands by 3L against a constant pressure of 3 atmosphere. Calculate the work done in :
(a) L. atmosphere (b) Joules
(c) Calories

Explanation

The work done (W) when the gas expands at constant pressure P(=3 atm) from volume `V_(1)` ti `V_(2)` is given by
`W=-int_(v_(1))^(v_(2))"P dv"`
`=-P int_(v_(1))^(v_(2))dv`
`=-P*(V_(2)-V_(1))=-PDeltaV`.
where, negative sigh indicates work done by the system.
Here `DeltaV=3L`
(a) `W=-PDeltaV=-3xx3L*atm=-9lit.atm.`
(b) We know, 1 L.atmosphere `=101*325J`
Thus `W=-9xx101*325J=-911*925` Joules
(c) We know, 1 Joule `=0*2390` calories
Thus, `W=-911*925xx0*2390Cal=-217*95`
calories.