Question

Which of the following statements is false? Select one: a. Diffusion rates are much slower than effusion rates. b. At a temperature of 298 K, the most probable speed of an O2 molecule is lower than that of a Ne atom. c. The kinetic molecular theory postulates that particles have essentially no volume. d. The most probable speed of an O2 molecule is higher at 298 K than at 197 K. e. At 298 K, the average kinetic energies of an O2 molecule and a He atom are different.

Answer 1

A) Effusion is escape of gas molecules through hole with diameter less than mean free path of the gas molecules. On the other hand diffusion is movement of gas molecules from higher concentration to lower. So; effusion is restricted process but diffusion is free process. So; effusion must be slower than diffusion.

Above statement is false.

B) When temperature is fixed; most probable speed of gas molecule is inversely proportional to the square root of molar mass of gad molecule. So; gas with low molecular weight should have higher value of most probable speed.Neon has lower molar mass than oxygen and Ne should have greater most probable speed than oxygen.

So; most probable speed of oxygen is lowercthan neon. The statement is true.

C) Kinetic theory of gas assumes gas molecules as points i.e volumeless.

So; the statement is true.

D) most probable speed of a gas molecule iscdirectly proportional to square root ofctemperature in kelvin scale. So; most probable speed is higher at higher temperature

The above statement isctrue.

E) At same temperature; average kinetic energy of different gases are same as kinetic energy of gases do not depend on molar mass.

So; the statement is false.

False statements are a and e.