Question

A gas absorbs 120 J of heat and expands against the external pressure of 1.10atm from a volume of 0.5 litre to 2.0 litre .What is the change in internal energy ? (1Latm =101.3J)

Answer 1

The step-by-step explanation is as follows.

We know that,
Work of expansion, w = PDV

DV = 2.0 - 0.5 =1.5L, P = 836 mm of Hg

PDV = 1.10 x 1.5

= 1.650 L atm

= 1.650 x 101.3 (1L atm = 101.3 J)

= 167.1 J

Since work is done by the system w = - 167.1 J

Heat absorbed by the system = 120J or q = + 120J

Now, DE = q + w

= 120 J + (-167.1) = - 47.1 J

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