Question

Suppose that 33.3 J of heat is added to an ideal gas. The gas expands at a constant pressure of 1.45 104 Pa while changing its volume from 3.24 10-4 to 8.40 10-4 m3. The gas is not monatomic, so the relation does not apply.(a) Determine the change in the internal energy of the gas.

Answer 1

ΔU = 25.8 J

Step-by-step explanation:

The gas absorbs 33.3 J of heat, that is, Q = 33.3 J.

The work (W) of expansion can be calculated using the following expression:

W = -P. ΔV

where,

P is the external pressure

ΔV is the change in volume

W = -1.45 × 10⁴ N . m⁻² × (8.40 × 10⁻⁴ m³ - 3.24 × 10⁻⁴ m³) = -7.48 J

The change in the internal energy (ΔU) is:

ΔU = Q + W

ΔU = 33.3 J + (-7.48 J) = 25.8 J