Water is, indeed, an exception. Normally when temperature drops, material shrinks. Water doesn't, water expands instead.
Answer:
T'=70.92°C
Explanation:
Given that
V= 100 L=0.1 m³
P=400 KPa
T=25°C
Work done on the air = 15 KJ
W= -15 KJ
If we assume that air is ideal gas
P V = m R T
R=0.287 KJ/kg.K for air
T= 273 + 25 = 298 K
By putting the values
P V = m R T
400 x 0.1 = m x 0.287 x 298
m=0.46 kg
From first law of thermodynamics
Q= ΔU +W
Insulated piston–cylinder , Q=0
ΔU = m Cv ΔT
ΔU = - W
Cv = 0.71 KJ/kg.k for air
0.46 x 0.71 x (T' -25) = 15
T'=70.92 °C
So the final temperature of air is T'=70.92 °C
