Free Gases MCQs with Answers
443 Gases MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Gas behaviour is explained through the kinetic molecular theory and the relationships among pressure, volume and temperature. Work includes STP, Boyle's and Charles's laws, absolute zero, the ideal gas equation, and the distinction between ideal and real gases, especially the effects of intermolecular forces and molecular volume.
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443 questions · page 2 of 23
- A. the product of the individual pressures
- B. the sum of the partial pressures of the component gases
- C. the average of the individual pressures
- D. the pressure of the heaviest gas
Explanation: Because ideal gas molecules do not interact, each gas exerts the pressure it would exert alone in the same volume, and these simply add.
Correct answer: the sum of the partial pressures of the component gases- A. directly proportional to its molar mass
- B. inversely proportional to the square root of its molar mass
- C. independent of its molar mass
- D. proportional to the square of its molar mass
Explanation: Lighter molecules move faster at a given temperature, so hydrogen diffuses four times as fast as oxygen, whose molar mass is sixteen times…
Correct answer: inversely proportional to the square root of its molar mass- A. the mass of the container
- B. the finite volume of the molecules and the attractive forces between them
- C. the speed of the molecules
- D. the colour of the gas
Explanation: The constant b subtracts the volume actually occupied by the molecules and the constant a adds back the pressure lost to intermolecular…
Correct answer: the finite volume of the molecules and the attractive forces between them- A. boiling point
- B. critical temperature
- C. melting point
- D. triple point
Explanation: Above the critical temperature no amount of pressure will produce a liquid, because the molecules have too much kinetic energy for the…
Correct answer: critical temperature- A. Boyle's law
- B. Charles's law
- C. Gay-Lussac's law
- D. Avogadro's law
Explanation: Gay-Lussac's law covers the pressure temperature relationship at constant volume, and it explains why a sealed aerosol can explode when…
Correct answer: Gay-Lussac's law- A. the identity of the gas
- B. the absolute temperature
- C. the pressure
- D. the volume of the container
Explanation: At the same temperature, hydrogen and oxygen molecules have the same average kinetic energy, though the lighter hydrogen molecules must…
Correct answer: the absolute temperature27. A fixed mass of gas at 2 atm and 300 K is heated to 600 K at constant volume. The new pressure is
- A. 1 atm
- B. 2 atm
- C. 4 atm
- D. 8 atm
Explanation: Pressure is proportional to absolute temperature at constant volume, so doubling the temperature in kelvin doubles the pressure to 4 atm.
Correct answer: 4 atm- A. Helium
- B. Ammonia
- C. Water vapour
- D. Carbon dioxide
Explanation: Helium is a small non polar monatomic gas with very weak dispersion forces and negligible molecular volume, so it comes closest to the…
Correct answer: Helium- A. zero
- B. exactly 1 at all pressures
- C. always greater than 1
- D. always less than 1
Explanation: By definition an ideal gas satisfies PV equal to nRT exactly, so Z is one under every condition.
Correct answer: exactly 1 at all pressures- A. 8.314
- B. 62.4
- C. 0.821
- D. 62400
Explanation: The universal gas constant is 8.314 joules per mole per kelvin, and this is the value to use whenever pressure is in pascals and volume in…
Correct answer: 8.314- A. P = 1 atm
- B. P = 2 atm
- C. P = 3 atm
- D. P = 0 atm
Explanation: Absolute zero is minus 273 degrees Celsius, and extrapolating a pressure against temperature graph for a fixed volume of ideal gas back to…
Correct answer: P = 0 atm- A. 0C°
- B. 273K
- C. 273.16C°
- D. -273.16C°
Explanation: Absolute zero is the lowest theoretical temperature, equal to 0 K and approximately -273.15 °C; many older chemistry texts state it as…
Correct answer: -273.16C°- A. 0?C
- B. 273.16K
- C. ?273.16 K
- D. ?273.16?C
Explanation: Charles's law gives V proportional to absolute temperature, so extrapolating a volume-temperature graph to zero volume gives T = 0 K =…
Correct answer: ?273.16?C- A. 1660
- B. 1661
- C. 1662
- D. 1663
Explanation: Robert Boyle published his gas-pressure investigations in 1662, establishing that pressure is inversely proportional to volume at constant…
Correct answer: 1662- A. 3P
- B. P/3
- C. 3P/T
- D. 6P
Explanation: At constant temperature, Boyle's law gives P1V1 = P2V2. If V2 = 3V1, then P2 = P1V1/(3V1) = P1/3, so the pressure becomes P/3 in the same…
Correct answer: P/3- A. 1/2dm3
- B. 1/3dm3
- C. 1/4dm3
- D. 2/3dm3Trying Interactive Physics Simulation Software
Explanation: At constant temperature, Boyle's law gives P1V1 = P2V2. Thus V2 = (2 atm)(1 dm3)/(6 atm) = 1/3 dm3.
Correct answer: 1/3dm3- A. Straight line parallel to x-axis
- B. Straight line parallel to y-axis
- C. Straight line
- D. Curve
Explanation: At constant temperature, Boyle's law gives PV = constant, so P = constant x 1/V.
Correct answer: Straight line- A. 1785
- B. 1787
- C. 1880
- D. 1885
Explanation: Jacques Charles studied the relationship between gas volume and temperature around 1787, although the law was later published and…
Correct answer: 178739. Pressure remain constant, at which temperature the volume of gas becomes twice of what it is at 0°C?
- A. 546 °C
- B. 546 K
- C. 200°C
- D. 273 K
Explanation: At constant pressure, Charles's law states that volume is proportional to absolute temperature.
Correct answer: 546 K- A. Boyles law
- B. Charles law
- C. Daltons law
- D. Grahams law
Explanation: Charles's law states that the volume of a fixed mass of gas is directly proportional to its absolute temperature at constant pressure, V/T…
Correct answer: Charles law