Kinetic Theory

Topics in this chapter

• Kinetic Theory Postulates and Pressure
• Mean Free Path and Collisions
• Molecular Speeds and Temperature
• Degrees of Freedom and Equipartition
• Specific Heats and Gamma
• Gas Mixtures and Dissociation
• Internal Energy, Heat, and Work

Cheat sheet

Practice questions

1. Question 1Q-2E0F1E

   At what temperature is the root mean square speed of hydrogen molecules equal to the root mean square speed of oxygen molecules at $27^{\circ}\text{C}$? (Molar mass of hydrogen = $2\text{ g/mol}$, Molar mass of oxygen = $32\text{ g/mol}$)

   1. A.$18.75\text{ K}$
   2. B.$300\text{ K}$
   3. C.$4800\text{ K}$
   4. D.$19.2\text{ K}$
   See the answer and solution
2. Question 2Q-E543F3

   A gas is kept in a rigid container. If the average translational kinetic energy of its molecules is increased by $4\%$, the percentage increase in the pressure of the gas is:

   1. A.$2\%$
   2. B.$4\%$
   3. C.$8\%$
   4. D.$0\%$
   See the answer and solution
3. Question 3Q-0A892E

   According to the law of equipartition of energy, what is the internal energy of $1\text{ mole}$ of a triatomic non-linear gas at absolute temperature $T$?

   1. A.$\frac{3}{2}RT$
   2. B.$\frac{5}{2}RT$
   3. C.$3RT$
   4. D.$\frac{7}{2}RT$
   See the answer and solution
4. Question 4Q-3A0430

   The root mean square speed of gas molecules is $v$ at pressure $P$ and temperature $T$. If the pressure is doubled keeping the temperature constant, the new root mean square speed will be:

   1. A.$v$
   2. B.$\sqrt{2}v$
   3. C.$2v$
   4. D.$v/\sqrt{2}$
   See the answer and solution
5. Question 5Q-AAC8DC

   Find the ratio of the root mean square speeds of oxygen molecules ($O_2$) and ozone molecules ($O_3$) at the same temperature.

   1. A.$\sqrt{\frac{3}{2}}$
   2. B.$\sqrt{\frac{2}{3}}$
   3. C.$\frac{3}{2}$
   4. D.$\sqrt{\frac{3}{5}}$
   See the answer and solution