A thermodynamic system absorbs 20 kJ of heat from its surroundings and simultaneously does 10 kJ of — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

According to the First Law of Thermodynamics, $\Delta U = q + w$. Heat absorbed by the system is positive ($q = +20 \text{ kJ}$). Work done by the system on the surroundings is negative ($w = -10 \text{ kJ}$). Therefore, $\Delta U = +20 - 10 = +10 \text{ kJ}$.