Answer: 13R/6.
- A 13R/6
- B 2R
- C 5R/2
- D 11R/6
Correct answer: A. 13R/6
Explanation: C<sub>v,mix</sub> = (n<sub>1</sub>C<sub>v1</sub> + n<sub>2</sub>C<sub>v2</sub>)/(n<sub>1</sub>+n<sub>2</sub>) = (1.5R + 5R)/3 = 6.5R/3 = 13R/6.
Not all gas molecules move at the same speed - the Maxwell-Boltzmann distribution shows the spread, with the most probable speed vp slightly less than the average vavg, which is slightly less than the root-mean-square speed vrms used in the pressure formula.
Concept context
Kinetic theory of gases connects molecular motion to pressure and temperature, explaining gas laws, specific heats, and molecular speeds.