An ideal gas in a piston is placed in a refrigerator, which removes 413 J of energy from the gas via cooling. The plunger on the piston is pushed down, which does 70 J of work on the gas.

1)

What is the net change in the internal energy of the gas in the piston?

The net change in the internal energy of the gas in the piston is - 343J

Explanation:

Because heat and workdone are the only means of energy transfer between the system and the surrounding, change in internal energy is given by;

∆E = q + w

q = heat transfer

w = workdone

Because heat is lost by the system, the heat transfer is negative

q = - 413J

Because work is done on the system, workdone is positive

w = + 70J

∆E = - 413J + 70J

∆E = - 343J