Asystem expands by 0.91m3 at a constant pressure
of 105 kpa.
(a) find the heat that flows into or out of
thesystem if its internal energy increases by 91 j.
(b) find the heat that flows into or out of the system if
itsinternal energy decreases by 1950j.

a)Q= 95.641 KJ

The heat will flow into the system.

b)Q= 93.600  KJ

The heat will flow into the system.

Explanation:

Given that

ΔV= 0.91 m³

P =105 KPa

From first law of thermodynamics

Q = ΔU + W

Q= ΔU +P ΔV

ΔU=Change in the internal energy

PΔV= Work done

Q=Heat transfer

a)

Q= ΔU +P ΔV

Given that ΔU = 91 J

Q= 91 + 0.91 x 105 x 1000 J

Q= 95641 J

Q= 95.641 KJ

The heat will flow into the system.

b)

Given that ΔU = -  1950 J

Q= -  1950 J+ 0.91 x 105 x 1000 J

Q= 93600 J

Q= 93.600  KJ

The heat will flow into the system.

Note- If the Q comes negative then it  means that heat will flow out of the system.