- When gas molecules collide, the momentum before the collision is equal to:
A) The momentum after the collision.
B) Zero.
C) The average kinetic energy.
D) The total pressure of the gas.
Answer: A) The momentum after the collision.
Explanation: According to the law of conservation of momentum, the total momentum before and after the collision remains the same in a closed system.
- In a gas, the internal energy is primarily due to:
A) Potential energy of the gas molecules.
B) Kinetic energy of the gas molecules.
C) Gravitational forces between molecules.
D) Intermolecular forces.
Answer: B) Kinetic energy of the gas molecules.
Explanation: The internal energy of an ideal gas is largely attributed to the kinetic energy of its molecules.
- What happens to the pressure of a gas if the volume is tripled while the temperature remains constant?
A) It increases threefold.
B) It decreases threefold.
C) It remains unchanged.
D) It becomes zero.
Answer: B) It decreases threefold.
Explanation: According to Boyle’s Law, if the volume increases, the pressure decreases inversely.
- The average speed of gas molecules is dependent on which of the following?
A) Only temperature.
B) Only pressure.
C) Temperature and molar mass.
D) Volume only.
Answer: C) Temperature and molar mass.
Explanation: The average speed of gas molecules is affected by both the temperature of the gas and its molar mass.
- What effect does decreasing the temperature of a gas at constant volume have on pressure?
A) Pressure increases.
B) Pressure decreases.
C) Pressure remains constant.
D) Pressure fluctuates.
Answer: B) Pressure decreases.
Explanation: According to Gay-Lussac’s Law, decreasing temperature at constant volume results in a decrease in pressure.
- The compressibility of a gas is defined as:
A) The ratio of its volume to its mass.
B) The ability of a gas to expand.
C) The ratio of its change in volume to the change in pressure.
D) The measure of gas density.
Answer: C) The ratio of its change in volume to the change in pressure.
Explanation: Compressibility is defined as the fractional change in volume per unit change in pressure.
- When comparing the rates of diffusion of two gases, if gas A has a higher molar mass than gas B, which of the following is true?
A) Gas A diffuses faster than gas B.
B) Gas A diffuses slower than gas B.
C) Both gases diffuse at the same rate.
D) The rate cannot be determined.
Answer: B) Gas A diffuses slower than gas B.
Explanation: According to Graham’s Law, the rate of diffusion is inversely proportional to the square root of the molar mass.
- The volume of a gas is halved and the temperature is held constant. What happens to the number of moles?
A) It remains the same.
B) It doubles.
C) It halves.
D) It becomes zero.
Answer: A) It remains the same.
Explanation: Halving the volume does not change the number of moles if the temperature remains constant; it just increases the pressure.
- The principle of equipartition of energy states that:
A) Energy is equally distributed among all forms of energy.
B) Each degree of freedom contributes equally to the energy.
C) Total energy is conserved in a closed system.
D) Kinetic energy is transformed into potential energy.
Answer: B) Each degree of freedom contributes equally to the energy.
- The process by which gas molecules randomly move from an area of high concentration to an area of low concentration is known as:
A) Diffusion.
B) Effusion.
C) Convection.
D) Conduction.
Answer: A) Diffusion.
Explanation: Diffusion is the process of random movement of molecules from an area of higher concentration to one of lower concentration until equilibrium is reached.
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