Question

Part A

Calculate ΔE, if q= 0.767 kJ and w= -820 J .

Part B

Determine whether the process is endothermic or exothermic.

Part C

Calculate ΔE, if a system releases 66.9 kJ of heat to its surroundings while the surroundings do 44.0 kJ of work on the system.

Part D

Determine whether the process is endothermic or exothermic.

Part E

Calculate ΔE, if the system absorbs 7.25 kJ of heat from the surroundings while its volume remains constant (assume that only P−V work can be done).

Part F

Determine whether the process is endothermic or exothermic.

Answer 1

A)

q = 0.767 KJ = 767 J

w = -820 J

ΔE = q + w

ΔE = 767 J - 820 J

ΔE = - 53 J

Answer: - 53 J

B)

Here q is positive. So heat is absorbed by the system

Hence it is endothermic

C)

q = - 66.9 KJ

w = 44.0 KJ

ΔE = q + w

ΔE = - 66.9 KJ + 44.0 KJ

ΔE = - 22.9 KJ

Answer: - 22.9 KJ

D)

since the system releases heat,

it is exothermic

E)

since volume is constant, work done = 0

q = 7.25 KJ

ΔE = q + w

ΔE = 7.25 KJ + 0

ΔE = 7.25 KJ

Answer: 7.25 KJ

F)

since the system absorbs heat,

it is endothermic