Question

Calculate the kinetic energy of 10 grams of argon molecules at 127 °C. [Universal gas constant R = 8310 J/kmol.K, atomic weight of argon = 40]

Answer 1

Data : M = 10 g = 10 × 10^-3 kg, T = 273 + 127 

= 400 K,R = 8310 J/kmol.K, M₀ = 40 kg/kmol

Kinetic energy per unit mass

= 15 × 8310 = 1.247 × 10⁵ J/kg

∴ The kinetic energy of 1 × 10^-3 kg of argon

at 127°C = 1.247 × 10⁵ × 10 × 10^-3 

= 1247 J