B. Gas molecules exert forces on each other only during collisions
C. The volume of gas molecules is negligible compared to the container volume
D. All of the above
2. The average kinetic energy of gas molecules is directly proportional to:
A. Pressure of the gas
B. Volume of the gas
C. Absolute temperature of the gas
D. Density of the gas
3. According to kinetic theory, pressure exerted by an ideal gas is due to:
A. Attractive forces between molecules
B. Collisions of molecules with the walls of container
C. Repulsive forces between molecules
D. Gravitational pull
4. Root mean square speed of gas molecules depends on:
A. Pressure only
B. Temperature only
C. Both pressure and temperature
D. Volume only
5. At constant temperature, if pressure of a gas is doubled, its density:
A. Becomes half
B. Becomes double
C. Remains same
D. Becomes four times
6. The mean free path of gas molecules increases when:
A. Density increases
B. Temperature decreases
C. Pressure increases
D. Pressure decreases
7. The ratio of specific heats (Cp/Cv) for monatomic gases is:
A. 1.33
B. 1.40
C. 1.67
D. 1.50
8. Real gases behave like ideal gases at:
A. High pressure and low temperature
B. High pressure and high temperature
C. Low pressure and high temperature
D. Low pressure and low temperature
9. The average kinetic energy of oxygen molecules at 27°C is:
A. 6.21 × 10⁻²¹ J
B. 4.14 × 10⁻²¹ J
C. 5.65 × 10⁻²¹ J
D. 3.11 × 10⁻²¹ J
10. The speed of sound in a gas is related to:
A. Most probable speed
B. Average speed
C. Root mean square speed
D. All of the above
Section B: Numerical Problems (10 × 2 = 20 Marks)
1. Calculate the root mean square speed of oxygen molecules at 27°C. (Molecular weight of O₂ = 32 g/mol, R = 8.31 J/mol·K)
2. A gas at 2 atm pressure occupies 5 liters at 300 K. How many moles of gas are present? (R = 0.0821 L·atm/mol·K)
3. Calculate the average kinetic energy of helium molecules at 127°C. (k = 1.38 × 10⁻²³ J/K)
4. The density of a gas is 1.78 g/L at STP. Calculate its molar mass.
5. If the rms speed of hydrogen molecules at a certain temperature is 1800 m/s, find the temperature. (Molecular weight of H₂ = 2 g/mol, R = 8.31 J/mol·K)
6. Calculate the pressure exerted by 10²³ molecules of oxygen each of mass 5.3 × 10⁻²⁶ kg in a 2 liter container with rms speed 400 m/s.
7. A mixture of 2 moles of hydrogen and 3 moles of helium is at 300 K. Find the average kinetic energy per molecule of the mixture.
8. At what temperature will the rms speed of oxygen molecules be twice that at 27°C?
9. Calculate the ratio of most probable speed to average speed for a gas at a given temperature.
10. The mean free path of nitrogen molecules at STP is 6.0 × 10⁻⁸ m. If the radius of nitrogen molecule is 1.0 × 10⁻¹⁰ m, calculate the number of molecules per unit volume.
Class 12 Chemistry Quiz | Solutions Willer Academy Class 12 Chemistry: Solutions (NEET & Board) Please select your language / कृपया अपनी भाषा चुनें: English हिंदी English + हिंदी Enter your name: Start Quiz Quiz: Solutions 20:00 Submit
Class 12 Chemistry Quiz | Surface Chemistry Willer Academy Class 12 Chemistry: Surface Chemistry (NEET & Board) Please select your language / कृपया अपनी भाषा चुनें: English हिंदी English + हिंदी Enter your name: Start Quiz Quiz: Surface Chemistry 20:00 Submit
