A system at constant pressure absorbs 1000 J of heat and expands by 0.4 L against 2.5 atm. What is Δ U? (1 atm·L = 101.3
w = -PΔ V = -2.5 × 0.4 × 101.3 = -101.3 J, q = 1000 J, Δ U = q + w = 1000 - 101.3 = 898.7 J.
Ref: NCERT Class 11 Chemistry > Chapter 5: Thermodynamics > Topic: Thermodynamic Terms - System Surroundings and Types of Systems