Question

The ratio of number of collisions per second at the walls of containers by he and o2 gas molecules kept at same volume and temperature, is (assume normal incidence on walls

Answer 1

Answer:

First, we will define Collision Frequency, it is defined as the number of collisions which take place in 1 second among the molecules present in 1cc of the gas.

Also, collision number (Nc) is the number of collisions which a single molecule undergoes with other molecules in 1 second.

So Nc=2πvo2n

Where v = average speed

O = molecular diameter

N = number of molecules

Collisions among molecules will be Nc∗n

Each collision requires 2 molecules, collision frequency

Z=(Nc∗n)/2=(½)∗πvo2n2Average speed (v)=sqrt(8RT/(πM)) where M is the molecular mass

Hence, Z=2o2n2sqrt(πRTM)

This is the required formula for this question

We know that M for 02 molecule is 32u and for Helium molecule is 4u

Hence z1/z2 = ratio of He to that of Oxygen = (const/sqrt4)∗(sqrt32/const)

= sqrt(8/1)

=22:1