Question

If heat given to a system is 6 kcal and work done is 6 kJ. Then change in internal energy is

• A. 19.1 kJ
• B. 12.5 kJ
• C. 25 kJ
• D. Zero

Answer 1

Answer: (A)

19.1 kJ

Answer 2

$\Delta Q = \Delta U + \Delta W$ ⇒ $\Delta U = \Delta Q - \Delta W$

$= 6 \times 4.18 - 6 = 19.08kJ \approx 19.1kJ$