Saved Bookmarks
| 1. |
Calculate the rms speed , average speed and the most probable speed of 1 mole of hydrogen molecules at 300K . Neglect the mass of electron. |
|
Answer» SOLUTION :The hydrogen atom has ONE proton and one electron. The mass of electron is negligible compared to the mass of proton `=1.67xx10^(-27)` kg One hydrogen molecule =2 hydrogen ATOMS `=2xx167xx10^(-27)` kg The average speed `barnu=sqrt((8kT)/(PIM))=1.60sqrt((kT)/m)` `=1.60sqrt(((1.38xx10^(-13))xx(300))/(2(1.67xx10^(-27))))=178xx10^(3)ms^(-1)` (Boltzmann Constant `k=1.38xx10^(-32)JK^(-1)`) The rms speed `nu_(rms)=sqrt((3kT)/m)=1.73sqrt((kT)/m)` `=1.73sqrt(((1.38xx10^(-23))xx(300))/(2(1.67xx10^(-27))))=1.93xx10^(3)ms^(-1)` Most probable speed `nu_(mp)=sqrt((2kT)/m)=1.41sqrt((kT)/m)` `=1.41sqrt(((1.38xx10^(-23))xx(300))/(2(1.67xx10^(-27))))=1.57xx10^(3)ms^(-1)` Note that `nu_(rms) gt barnu gt nu_(mp)` |
|