Answer :
Final answer:
The change in internal energy of the system is calculated using the first law of thermodynamics as ΔU = Q - W. Since 56 kJ of work is done on the system and it releases 85 kJ of heat, the change in internal energy is B) -141 kJ.
Explanation:
If 56 kJ of work is done on a system and the system releases 85 kJ of heat, the change in the internal energy of the system can be calculated using the first law of thermodynamics, which states that the change in internal energy (ΔU) is equal to the heat added to the system (Q) minus the work done by the system (W). In this case, the work is done on the system, so its sign is positive when calculating the internal energy change.
Using the formula ΔU = Q - W, we substitute the given values (ΔU = (-85 kJ) - (56 kJ)) since the heat is released from the system, which gives us ΔU = -141 kJ. Therefore, the correct answer is B) -141 kJ.
