Concepts Of Physics MCQ Edition [Volume 2]PhysicsKinetic Theory of Gases
Hydrogen gas is confined within a closed vessel at 1 atm ( 100 kPa ) and 300 K . Determine the mean speed of the molecules.
Options
- A2520 m s ⁻¹
- B1930 m s ⁻¹
- C1580 m s ⁻¹
- D1780 m s ⁻¹
Correct answer
D. 1780 m s ⁻¹
Step-by-step solution
The mean speed of gas molecules is given by the formula: v_ mean = 8RT M For hydrogen gas ( H₂ ), the molar mass is M = 2 10⁻³ kg mol ⁻¹ . Substituting T = 300 K and R = 8.314 J mol ⁻¹ K ⁻¹ : v_ mean = 8 8.314 300 2 10⁻³ v_ mean = 19953.6 6.283 10⁻³ v_ mean = 3.17 10^6 1780 m s ⁻¹