Two moles of a monatomic ideal gas are heated at constant pressure from $300 K$ to $400 K$ . Taking $R = 8.314 J mo l^{- 1} K^{- 1}$ , calculate $Δ U$ of the gas in joules (nearest integer).

Numerical answer type, answer in J, tolerance 1.

Answer: 2494 J

For an ideal gas

Δ U = n C_{V} Δ T

for any process, with

C_{V} = \frac{3}{2} R

for a monatomic gas.

Δ U = 2 \times 1.5 \times 8.314 \times 100 = 2494.2 J

, i.e. about 2494 J.