- What is the primary reason for gas expansion?
A) Decreasing temperature.
B) Increasing temperature.
C) Decreasing volume.
D) Increasing pressure.
Answer: B) Increasing temperature.
Explanation: Gases expand when temperature increases because the kinetic energy of the molecules rises, causing them to move apart.
- The phenomenon where a gas diffuses faster than another gas is explained by which law?
A) Charles’s Law.
B) Avogadro’s Law.
C) Graham’s Law.
D) Dalton’s Law.
Answer: C) Graham’s Law.
Explanation: Graham’s Law states that the rate of diffusion of a gas is inversely proportional to the square root of its molar mass.
- The kinetic theory assumes that the average distance between gas molecules is:
A) Constant regardless of conditions.
B) Negligible compared to the volume of the gas.
C) Always large.
D) Zero.
Answer: B) Negligible compared to the volume of the gas.
Explanation: The theory assumes that the size of individual gas molecules is negligible compared to the overall volume they occupy.
- What is the effect of increasing the molar mass of a gas on its root mean square speed?
A) Increases the speed.
B) Decreases the speed.
C) Does not affect the speed.
D) Makes it zero.
Answer: B) Decreases the speed.
Explanation: The root mean square speed is inversely proportional to the square root of the molar mass; thus, higher molar mass results in lower speed.
- Which of the following gases is least likely to behave ideally?
A) Helium (He)
B) Neon (Ne)
C) Ammonia (NH3)
D) Argon (Ar)
Answer: C) Ammonia (NH3)
Explanation: Ammonia has strong intermolecular forces due to its polarity, leading to significant deviations from ideal gas behavior.
- If the pressure of a gas is halved while its volume is doubled, what happens to the temperature?
A) It remains the same.
B) It doubles.
C) It halves.
D) It quadruples.
Answer: A) It remains the same.
Explanation: According to the ideal gas law, if pressure is halved and volume is doubled, the temperature remains constant.
- The average kinetic energy of gas molecules at absolute zero is:
A) Zero.
B) Maximum.
C) Unchanged.
D) Undefined.
Answer: A) Zero.
Explanation: At absolute zero (0 K), the kinetic energy of molecules theoretically reaches its minimum, which is zero.
- A gas expands in a piston while absorbing heat. This process is called:
A) Isothermal expansion.
B) Adiabatic expansion.
C) Isochoric expansion.
D) Isobaric expansion.
Answer: A) Isothermal expansion.
Explanation: In an isothermal expansion, the gas absorbs heat while expanding at a constant temperature.
- The law that states the volume of gas is directly proportional to the number of moles 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 equal volumes of gases at the same temperature and pressure contain an equal number of molecules.
- The rate of a gas’s diffusion is affected by:
A) The molecular weight of the gas.
B) The temperature of the gas.
C) The density of the gas.
D) All of the above.
Answer: D) All of the above.
Explanation: The rate of diffusion is influenced by molecular weight, temperature, and density, all of which affect how quickly a gas can spread.
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