(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.

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