JEE Main2014ChemistryStates of MatterActual
The temperature at which oxygen molecules have the same root mean square speed as helium atoms have at 300 K is : (Atomic masses : He = 4 u, O = 16 u)
Options
- A600 K
- B2400 K
- C1200 K
- D300 K
Correct answer
B. 2400 K
Step-by-step solution
C rms = 3 RT M C rms He = 3 R × 3 0 0 4 & C rms O 2 = 3 R × T O 2 3 2 ∴ ( C r m s ) H e = ( C r m s ) O 2 ⇒ 3 R × 300 4 = 3R × T O 2 32 T O 2 = 3 0 0 × 3 2 4 = 2 4 0 0 K