Question

(Thermodynamics)

1. For each system below, calculate the value for ∆E. Show equation and work!

A) A system does kJ of work and gives off 220 kJ of heat.

B) A system does 50 kJ of work and absorbs 65 kJ of heat.

C) A system has 120 kJ of work done on it and gives off 50 kJ of heat.​

Answer 1

A) -270 kJ; B) +15 kJ; C) + 70 kJ

Step-by-step explanation:

ΔE = q + w

By convention, anything leaving the system is negative and anything entering the system is positive.

A) ΔE = -220 kJ - 50 kJ = -270 kJ

B) ΔE = +65 kJ - 50 kJ = +15 kJ

C) ΔE = -50 kJ + 120 kJ = +70 kJ