Q1: Work required for compression of a gas contained in a cylinder is 7000 kJ. During compression, heat interaction of 3000 kJ causes the surroundings to be heated. Internal energy change of the gas during the compression is __________ kJ.

ANS:A - +4000

• Heat interaction (Q) during compression = 3000 kJ (added to the system)
• Work done (W) during compression = -7000 kJ (work done by the system, negative because work is done on the gas during compression)

We can use the first law of thermodynamics, which states that the change in internal energy (ΔU) of a system is equal to the heat added to the system minus the work done by the system. ΔU=Q−W Substituting the given values: Δ=3000 kJ−(−7000 kJ)ΔU=3000kJ−(−7000kJ) Δ=3000 kJ+7000 kJΔU=3000kJ+7000kJ Δ=10000 kJΔU=10000kJ So, the internal energy change of the gas during compression is +10000 kJ+10000kJ, not +4000 kJ+4000kJ. Apologies for the confusion. The correct explanation is that the internal energy change is +10000 kJ+10000kJ, not +4000 kJ+4000kJ.