Collision diameter

1
Collision diameter

• The closest distance of approach between the
  centres of the molecules taking part in a
  collision is called collision diameter.it is
  usally represented by s.

s
2
Collision Number and Collision frequency

• The no of collision which a single molecules
  makes with other molecules in one second is
  called collision number.
• On the basis of kinectic theory of gases,it can
  be shown that in gas containing n identical
  molecules per cm3,the no of collision which a
  single molecules will undergo with other
  molecules in one sec is given by
• Nc v2p?s2n
• Where vaverage velocity of the gas molecules in
  cm per sec
• smolecular diameter in cm
• nno of molecules/cm3

3
Movement of molecules A assuming other molecules
to be stationary
Consider a particular molecule A moving in a
particular direction .if average speed of the
molecule is v cm/sec,I twill travel a distance of
v cm in one second.if only A is supposed to move
and all other molecules are supposed to be
stationary, A will collide in 1 sec with all the
molecules whose centres lie within the cylinder
of length v cm and radius equal to molecular
diameter s as shown in fiqure.
4
Types of molecular collisions

• (a) (b)
  (c)
• Relative velocity0 Relative velocity2v
  Relative velocityv2?