According to the First Law of Thermodynamics, the heat added to a thermodynamic system minus the work done by the system is equal to which of the following?

• A. The temperature change of the system (ΔT)
• B. The change in internal energy of the system (ΔU)
• C. The change in entropy of the system (ΔS)
• D. The change in enthalpy of the system (ΔH)

Answer: (B)

Verified step by step guidance

1. Recall the First Law of Thermodynamics, which states that the change in internal energy of a system (\( \Delta U \)) is equal to the heat added to the system (\( q \)) minus the work done by the system (\( w \)).
2. Express this relationship mathematically as: \[ \Delta U = q - w \]
3. Understand that \( \Delta U \) represents the change in the internal energy of the system, which accounts for all energy changes within the system due to heat and work interactions.
4. Recognize that temperature change (\( \Delta T \)), entropy change (\( \Delta S \)), and enthalpy change (\( \Delta H \)) are different thermodynamic properties and are not directly equal to \( q - w \).
5. Conclude that according to the First Law of Thermodynamics, the quantity \( q - w \) corresponds specifically to the change in internal energy (\( \Delta U \)) of the system.