Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
This equation represents the first law of thermodynamics which states that the change in internal energy (ΔU) is equal to the heat added to a system (Q) plus the work done by or on the system (W).