Question

At what temperature the molecules of nitrogen will have the same r.m.s. velocity as the molecules of oxygen at 127°C

• A. 77°C
• B. 350°C
• C. 273°C
• D. 457°C

Answer 1

Answer: (A)

77°C

Answer 2

$v_{rms} = \sqrt{\frac{3RT}{M}}$Ž$T \propto M$ $\lbrack\because v_{rms},R \rightarrow \text{constant}\rbrack$

Ž$\frac{T_{N_{2}}}{T_{O_{2}}} = \frac{M_{N_{2}}}{M_{O_{2}}}$Ž $\frac{T_{N_{2}}}{(273 + 127)} = \frac{28}{32}$

Ž$T_{N_{2}} = 350K = 77{^\circ}C$