A gas occupies 2 litre at STP. It is provided 300 joule heat so that its volume becomes 2.5 litre at 1atm. Calculate change in its internal energy.

Explanation

`therefore` Work is carried out at constant P and thus irreversible.
Work done `=-P xx DeltaV`
`=1 xx (2.5-2.0)`
`=-0.5` litre atm
`=(-0.5 xx 1.987 xx 4.184)/0.0821` joule `=-50.63` J
From I law of thermodynamics.
`therefore q = DeltaE -W`
`300 = DeltaE + 50.63`
`therefore DeltaE = 2429.37` joule.