The molar heat capacity for an ideal gas at constant pressure is $20.785 J K^{- 1} mol^{- 1}$ . The change in internal energy is 5000 J upon heating it from 300 K to 500 K . The number of moles of the gas at constant volume is ..........[Nearest integer]
(Given: R = 8.314 J K^-1 mol^-1)

Question

The molar heat capacity for an ideal gas at constant pressure is $20.785 J K^{- 1} mol^{- 1}$ . The change in internal energy is 5000 J upon heating it from 300 K to 500 K . The number of moles of the gas at constant volume is ..........[Nearest integer]

(Given: R = 8.314 J K^-1 mol^-1)

TestHub · Accepted Answer

C p , m ​ = C v , m ​ + R ⇒ C v , m ​ = 20.785 − 8.314 = 12.471 J K − 1 m o l − 1 Δ U = n C v , m ​ Δ T ⇒ n = 12.471 × 200 5000 ​ = 12.471 25 ​ ≈ 2

Chemistry - Thermodynamics - I Question with Solution | TestHub

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