When the amount of heat 17 kJ is transferred to the gas, it performs work equal to 50 kJ.

When the amount of heat 17 kJ is transferred to the gas, it performs work equal to 50 kJ. What is the change in the internal energy of the gas? Has the gas cooled or heated up?

Q = 17 kJ = 17000 J.
A = 50 kJ = 50,000 J.
ΔU -?
According to the first law of thermodynamics, the amount of heat Q that is transferred to the gas goes to increase the internal energy ΔU or to perform work on external forces A: Q = ΔU + A.
ΔU = U2 – U1.
U2 – U1 = Q – A.
U2 – U1 = 17,000 J – 50,000 J = – 33,000 J.
From the ratio we see that the internal energy of the gas has decreased by 33,000 J.
Since the internal energy depends on temperature, the gas cooled down during the work.
Answer: the internal energy of the gas decreased by ΔU = 33000 J, the gas cooled down.