A gas under constant pressure of 4.5 xx 10^(5) Pa when subjected to 800 kJ of heat, changes the volume from 0.5 m^(3) to 2.0 m^(3). The change in internal energy of the gas is

A gas under constant pressure of 4.5 xx 10^(5) Pa when subjected to 80

1.	A gas under constant pressure of 4.5 xx 10^(5) Pa when subjected to 800 kJ of heat, changes the volume from 0.5 m^(3) to 2.0 m^(3). The change in internal energy of the gas is
Answer» `6.75 xx 10^(5) J` `5.25 xx 10^(5) J` `3.25 xx 10^(5) j` `1.25 xx 10^(5) J` SOLUTION :Here, `P = 4.5 xx 10^(5) Pa, DELTA Q = 800 kJ, V_(1) = 0.5 m^(3), V_(2) = 2m^(3)` The work done by the gas is `Delta W = P Delta V = P(V_(2) - V_(1)) = 4.5 xx 10^(5) (2-0.5) = 6.75 xx 10^(5) J` From the first law of thermodynamics, the change in internal energy is `Delta U = Delta Q - Delta W = 800 xx 10^(3) - 6.75 xx 10^(5) = 1.25 xx 10^(5)J`