Concepts Of Physics MCQ Edition [Volume 2]PhysicsKinetic Theory of Gases
In a gas, the rms speed of oxygen molecules is v . If the temperature is doubled and the oxygen molecules dissociate into oxygen atoms, the new rms speed will be
Options
- A2v
- Bv 2
- Cv
- D4v
Correct answer
A. 2v
Step-by-step solution
The initial rms speed of oxygen molecules is given by: v = 3RT M where M is the molar mass of O₂ molecules. When the temperature is doubled, the new temperature is T' = 2T . When oxygen molecules dissociate into oxygen atoms, the molar mass becomes half, so M' = M 2 . The new rms speed v' is given by: v' = 3RT' M' = 3R(2T) M 2 v' = 4 3RT M = 2 3RT M v' = 2v