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. The specific heat of helium at constant volume is closest to:

2. According to Graham’s law, the rate of diffusion or effusion is:

3. The failure of classical predictions of specific heat at low temperatures is explained by:

4. Which of the following best describes a polar covalent bond?

5. Why are heterogeneous catalysts often used instead of homogeneous ones in industry?

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

7. For a lubricant in a bearing, power lost due to viscous drag is: If shear stress , area , velocity , calculate power loss.

8. Which assumption of kinetic theory is violated when gases show liquefaction at high pressure?

9. Brownian motion provides strong evidence for:

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

11. Which experimental observation validates the Maxwell–Boltzmann distribution of molecular speeds?

12. Why does a monatomic ideal gas have ?

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

14. Which kinetic theory expression relates pressure to molecular speed distribution?

15. A sealed container holds water at equilibrium at 100 °C. If the pressure is suddenly reduced, what happens to the boiling point?

16. Which law can be derived from the kinetic theory assumption that average kinetic energy is proportional to absolute temperature?

17. If the pressure of a gas is kept constant and the temperature is doubled, what happens to the mean free path?

18. Why does Brownian motion become less visible in very viscous liquids like honey?

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

20. In kinetic theory, what is assumed about the time of collision between two molecules?

21. Which principle is used in designing catalytic converters for automobiles?

22. Which statistical distribution applies to indistinguishable particles with half-integer spin (electrons, protons, neutrons)?

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

24. Einstein’s explanation of Brownian motion is considered a bridge between:

25. Which of the following correctly describes atomic orbitals?

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

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

28. The latent heat equation during condensation of a mass of vapor is:

29. Which scientist first explained the cause of Brownian motion theoretically?

30. The Clausius–Clapeyron equation for vaporization is:

1. Effusion of gases is best described as:

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

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

4. In statistical mechanics, first-order phase transitions are characterized by:

5. The entropy in terms of microstates is given by Boltzmann’s formula:

6. Why does viscosity of gases increase with temperature? Use .

7. Which of the following is NOT an assumption of kinetic theory for an ideal gas?

8. White dwarfs in astrophysics are supported against gravitational collapse by:

9. Thermal conductivity () of a material is defined by Fourier’s law of heat conduction:

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

11. What is the principal quantum number associated with?

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

13. If a gas occupies 4 L at 2 atm pressure, what volume will it occupy at 1 atm, assuming constant temperature?

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

15. In a viscometer test, water takes 90 s to flow through a tube, while a liquid of density takes 150 s. If viscosity of water is , find viscosity of liquid.

16. Which of the following liquids has the highest surface tension?

17. At high temperatures, vibrational modes in molecules become active. How does this affect heat capacity?

18. The mean free path is inversely proportional to:

19. Einstein’s theory of Brownian motion provided a way to calculate:

20. In chemical engineering, viscosity affects mass transport. Diffusion coefficient is approximated by Stokes–Einstein relation: For a particle radius in water at 300 K (), calculate . ()

21. Which type of graph is obtained when pressure is plotted against for a fixed mass of gas at constant temperature?

22. How does increasing concentration of reactants affect reaction rate?

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

24. The root mean square speed of nitrogen at 300 K is given by: where . Find .

25. For a linear triatomic molecule at high temperature, the expected using kinetic theory is:

26. In the Maxwell–Boltzmann speed distribution curve, the area under the curve represents:

27. Why does a monatomic ideal gas have ?

28. If a copper rod of cross-sectional area , length , and conducts of heat, what is the temperature difference across its ends?

29. Calculate ratio of rms speeds of H and O at same temperature.

30. The ratio of rates of effusion of hydrogen and oxygen is:

31. The pressure drop in laminar flow through a tube is given by: For oil of viscosity , flow rate , tube length , and radius , calculate .

32. Which of the following gases has the largest Van der Waals constant ?

33. Which assumption of kinetic theory explains why pressure of a gas arises?

34. The Arrhenius equation relates rate constant to activation energy:

35. The average speed of molecules in Maxwell–Boltzmann distribution is:

36. At 373 K, the enthalpy of vaporization of water is . Using Clausius–Clapeyron, calculate at 1 atm ().

37. How does pressure affect the mean free path of a gas?

38. If the volume of a gas increases three times at constant temperature, its pressure will:

39. Joule’s contribution to kinetic theory was primarily through:

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

41. Why does kinetic theory correctly predict viscosity of gases but not liquids?

42. A steel sphere of radius falls through oil of density . The sphere density is , terminal velocity . Find viscosity of oil.

43. For 1 mole of an ideal gas, the total translational kinetic energy is:

44. The failure of equipartition theorem at very low temperatures is explained by:

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

46. Which of the following compounds contains polar covalent bonds?

47. The fluctuation–dissipation relation links heat capacity to energy fluctuations:

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

49. 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.

50. The specific heat capacity at constant volume of an ideal gas can be calculated using: