- If the number of gas molecules in a container is doubled while keeping the temperature and volume constant, what happens to the pressure?
A) It remains constant.
B) It doubles.
C) It triples.
D) It halves.
Answer: B) It doubles.
Explanation: According to Avogadro’s Law, doubling the number of gas molecules while keeping volume and temperature constant will double the pressure.
- What happens to the average kinetic energy of gas molecules when the gas is cooled?
A) It increases.
B) It remains constant.
C) It decreases.
D) It becomes zero.
Answer: C) It decreases.
Explanation: Cooling a gas reduces the kinetic energy of its molecules, which is reflected in a decrease in temperature.
- The law that describes the relationship between the volume and number of moles of a gas at constant temperature and pressure is known as:
A) Boyle’s Law.
B) Charles’s Law.
C) Avogadro’s Law.
D) Dalton’s Law.
Answer: C) Avogadro’s Law.
Explanation: Avogadro’s Law states that the volume of a gas is directly proportional to the number of moles when temperature and pressure are constant.
- Which of the following best describes the behavior of gas molecules at absolute zero?
A) They move freely.
B) They are in constant motion.
C) They have minimal kinetic energy.
D) They exert pressure.
Answer: C) They have minimal kinetic energy.
Explanation: At absolute zero (0 K), the kinetic energy of gas molecules approaches zero, theoretically stopping their motion.
- In the context of gas behavior, “real gases” deviate from ideal behavior due to:
A) Perfect elastic collisions.
B) Finite volume of molecules and intermolecular forces.
C) High temperatures.
D) Large volumes.
Answer: B) Finite volume of molecules and intermolecular forces.
Explanation: Real gases exhibit deviations from ideal behavior primarily because of the volume of molecules and the presence of intermolecular forces.
- The concept of “work” done by a gas during expansion can be calculated using:
A) PΔV
B) PV
C) nRT
D) PV
Answer: A) PΔV
Explanation: The work done by a gas during expansion or compression is calculated using the formula
W=PΔV.
- The process by which a gas cools when it expands is known as:
A) Isothermal expansion.
B) Adiabatic expansion.
C) Isochoric expansion.
D) Isobaric expansion.
Answer: B) Adiabatic expansion.
Explanation: During adiabatic expansion, a gas does not exchange heat with its surroundings, leading to a decrease in temperature as it expands.
- The temperature at which a gas theoretically has zero kinetic energy is:
A) 0 °C
B) 0 K
C) -273 °C
D) Both B and C
Answer: D) Both B and C
Explanation: Absolute zero (0 K or -273 °C) is the theoretical temperature at which gas molecules have minimum kinetic energy.
- Which of the following phenomena describes gas mixing?
A) Diffusion.
B) Effusion.
C) Conduction.
D) Radiation.
Answer: A) Diffusion.
Explanation: Diffusion is the process where gas molecules spread out and mix due to their random motion.
- In a closed system, what happens to the total number of gas molecules over time?
A) It increases.
B) It decreases.
C) It remains constant.
D) It fluctuates.
Answer: C) It remains constant.
Explanation: In a closed system, the total number of gas molecules remains constant unless there is a reaction or external influence.
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