Class 11 Physics — Chapter 13: Kinetic Theory Online Test

1. The escape velocity from Earth is . At what temperature would rms velocity of hydrogen molecules equal escape velocity? M = 0.002 kg/mol.

2. Reynolds number is given by: Air () flows at velocity through a pipe of diameter . Calculate Reynolds number.

3. For a cylindrical pipe of length , inner radius , outer radius , and , temperature difference is . Calculate heat transfer per second.

4. If nitrogen gas has mean free path and average molecular speed , calculate diffusion coefficient.

5. If the enthalpy of vaporization of liquid helium at 4.2 K is , calculate the entropy change per mole during vaporization.

6. A 250 g block of ice at 0 °C is converted into water at 0 °C. Find the entropy change of the system. (, )

7. The macroscopic law is derived microscopically using:

8. Entropy () connects microscopic and macroscopic descriptions by the relation:

9. The Boltzmann constant () relates:

10. According to Arrhenius equation , how does temperature affect rate constant?

11. In chemical engineering, the diffusion coefficient for gases is often estimated using kinetic theory as:

12. Why is Brownian motion critical in nanomedicine for drug delivery systems?

13. According to Einstein’s 1905 explanation, the random motion of suspended particles in Brownian motion is caused by:

14. The mean free path is inversely proportional to:

15. A gas has . If 5 moles of this gas are heated at constant volume through 40 K, how much heat is absorbed?

16. The work done by an ideal gas in an isothermal process from to is:

17. According to the law of equipartition, the average energy per molecule of a monatomic ideal gas is:

18. For a monatomic ideal gas, the total average energy per molecule according to equipartition theorem is:

19. What happens to the pressure of a gas if the rms speed of its molecules doubles at constant volume?

20. Which formula relates pressure , number density , molecular mass , and mean square speed ?

1. According to Einstein’s 1905 explanation, the random motion of suspended particles in Brownian motion is caused by:

2. Who was the first scientist to propose that matter is made up of indivisible particles called “atoms”?

3. Einstein’s expression for the diffusion coefficient of spherical particles of radius suspended in a fluid of viscosity is:

4. A vessel contains helium at 300 K and pressure . If average kinetic energy per atom = , calculate energy of 1 mole.

5. The Maxwell–Boltzmann distribution provides a molecular basis for which thermodynamic law?

6. How does kinetic theory explain the pressure exerted by liquids in a container?

7. A composite wall has two layers in series: thickness of brick () and of plaster (). If area = and , calculate heat flow per second.

8. Why does viscosity of the medium affect Brownian motion?

9. Which catalyst is used in the Haber process for ammonia synthesis?

10. The Boltzmann constant () relates:

11. According to kinetic theory, pressure of a gas arises due to:

12. A glycerin sample flows through a capillary of radius , length , under a pressure difference of . If volume flow rate is measured as , calculate viscosity.

13. The work done by an ideal gas in an isothermal process from to is:

14. The rate of most chemical reactions approximately doubles when temperature increases by:

15. Why does Van der Waals equation reduce to the ideal gas equation at low pressure and high temperature?

16. Why are neutron stars denser than white dwarfs?

17. The adiabatic index for a monatomic gas is:

18. Which of the following does NOT affect the rate of a chemical reaction?

19. According to Arrhenius equation , how does temperature affect rate constant?

20. Calculate the molar heat capacity ratio () for a monatomic ideal gas.

21. The mean free path of air molecules at 1 atm is . What will it be at pressure of , at same temperature?

22. Which scientist discovered the relationship now known as Charles’s law?

23. Why does ice float on water, considering kinetic theory and molecular structure?

24. Which of the following is NOT true for covalent bonds?

25. Which type of bonding explains why aluminum is both strong and a good conductor of electricity?

26. Which of the following best demonstrates Boyle’s law in real life?

27. For a first-order phase transition, the Clausius–Clapeyron relation is:

28. Which experimental observation best supports Avogadro’s law?

29. What is the main postulate of kinetic theory of gases?

30. A refrigerator extracts 200 kJ of heat from water at . How many grams of ice are formed? .

1. Which of the following best describes dipole–dipole forces?

2. In the Van der Waals equation , what does the constant represent?

3. If the pressure of a gas is doubled at constant temperature, the mean free path will:

4. For hydrogen gas at 300 K, calculate ratio of average speed to rms speed:

5. Which distribution applies to indistinguishable particles with integer spin (photons, helium-4 atoms)?

6. In an experiment, the time of flow of 50 ml of a liquid through an Ostwald viscometer is 120 s, while that of water (viscosity = 0.001 Pa·s) is 100 s. If densities of the liquid and water are and respectively, calculate viscosity of the liquid.

7. The ideal gas equation is consistent with kinetic theory because:

8. The macroscopic quantity pressure in a gas arises microscopically from:

9. Which industrial process uses finely divided platinum as a catalyst?

10. Which scientist proposed corrections to the ideal gas law to account for real gas behavior?

11. Which property of gases can be directly explained using the concept of mean free path?

12. Which relation connects diffusion coefficient , mean free path , and molecular speed ?

13. Which of the following is NOT an assumption of kinetic theory?

14. The specific heat at constant pressure near second-order transitions often diverges as:

15. Why is boiling considered a first-order phase transition?

16. Charles’s law states that for a fixed mass of gas at constant pressure:

17. If two gases and have molar masses and , the ratio of their rates of diffusion is:

18. The mean free path of a gas molecule is defined as:

19. The order of molecular speeds at a given temperature is:

20. A composite wall has two layers in series: thickness of brick () and of plaster (). If area = and , calculate heat flow per second.

21. Calculate the amount of heat required to melt 500 g of ice at . Latent heat of fusion of ice .

22. At intermediate pressures, real gases often show compressibility factor . What does this indicate?

23. Why does ice float on water, considering kinetic theory and molecular structure?

24. For a first-order phase transition, the Clausius–Clapeyron relation is:

25. Which term in the Van der Waals equation accounts for molecular attractions?

26. A gas effuses 1.414 times faster than oxygen. What is its molar mass?

27. Which of the following statements about ionic bonds is correct?

28. Which equation derived by Einstein relates mean squared displacement in Brownian motion to time?

29. Why does ice float on water in terms of phase transition properties?

30. What is the main postulate of kinetic theory of gases?

31. If the pressure of a gas is reduced to half at constant temperature, what happens to mean free path?

32. If mean free path is proportional to , what happens to when temperature doubles and pressure halves?

33. For water at 1 atm, the enthalpy of vaporization is approximately . Calculate the heat needed to vaporize 18 g (1 mol) of water.

34. The probability of a system being in a microstate with energy is:

35. In chemical engineering, the diffusion coefficient for gases is often estimated using kinetic theory as:

36. Which of the following explains why carbon dioxide liquefies more easily than oxygen?

37. For a linear triatomic molecule at high temperature where vibrational modes are active, the average energy per molecule becomes:

38. Which of the following does NOT affect the rate of a chemical reaction?

39. Which distribution describes the probability of molecular speeds in an ideal gas?

40. The Clausius–Clapeyron equation predicts that vapor pressure varies approximately as:

41. For a monatomic ideal gas, the molar heat capacity at constant volume () is:

42. In enzyme catalysis, the “lock and key model” explains:

43. The dimension of thermal conductivity in SI units is:

44. Why does Maxwell–Boltzmann distribution predict that some molecules always exceed escape velocity from Earth?

45. If air at STP has molecular diameter and number density , calculate mean free path.

46. Why is the factor of important in determining mean free path?

47. Isotopes of an element have:

48. In chemical reactors, gas mixing efficiency is strongly influenced by:

49. Which property of liquids is most influenced by intermolecular forces?

50. Which ensemble is used for a system at fixed temperature, volume, and chemical potential (allowing particle exchange)?