Boyle's law states that at constant temperature, the volume of a fixed mass of gas is
- A.Directly proportional to its pressure
- B.Inversely proportional to its pressure
- C.Independent of its pressure
- D.Proportional to the square of its pressure
Correct answer
Explanation
The correct answer is B, inversely proportional to its pressure. Boyle's law, established in 1662, says that for a fixed mass of gas at constant temperature the product of pressure and volume stays constant, so doubling the pressure halves the volume. On a graph, pressure against volume is a curve called an isotherm, while pressure against the reciprocal of volume is a straight line through the origin. A, directly proportional to its pressure is wrong because squeezing a gas never expands it. C, independent of its pressure describes a solid or a liquid, which are nearly incompressible, not a gas. D, proportional to the square of its pressure is not a gas law at all. The direct proportion with temperature belongs to Charles's law at constant pressure, and the direct proportion of pressure with temperature at constant volume belongs to the pressure law of Gay-Lussac.
Read the full article: Gas Laws and Kinetic Theory of Gases: Formulas and PYQs
Practice Questions
View allA hot air balloon rises because warm air
- A.Becomes denser than the surrounding air
- B.Expands and becomes less dense than the surrounding air
- C.Loses its mass on heating
- D.Has a lower specific heat than cold air
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By Charles's law the volume of a fixed mass of gas at constant pressure is proportional to its absolute temperature, so heating the air inside the envelope makes it expand; some of it escapes from the open mouth, the mass of air left inside falls, its density becomes lower than…
Read the full explanation →Absolute zero of temperature is equal to
- A.0 degrees Celsius
- B.-100 degrees Celsius
- C.-273.15 degrees Celsius
- D.-373.15 degrees Celsius
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Extending the straight line of Charles's law backwards shows that the volume of an ideal gas would become zero at minus 273.15 degrees Celsius, and this point is taken as the zero of the kelvin or absolute scale, at which molecular motion carries its least possible energy.
Read the full explanation →In the ideal gas equation PV = nRT, the value of the universal gas constant R in SI units is
- A.0.0821
- B.8.314
- C.1.987
- D.6.022
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In SI units the universal gas constant is 8.314 joule per mole per kelvin, obtained by multiplying the Boltzmann constant by the Avogadro number.
Read the full explanation →The volume occupied by one mole of an ideal gas at 273.15 K and one atmosphere pressure is about
- A.11.2 litres
- B.22.4 litres
- C.44.8 litres
- D.1 litre
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Substituting one mole, 273.15 kelvin and one atmosphere in the ideal gas equation gives a volume of 22.4 litres, the molar volume at standard temperature and pressure, and this is the figure used in mole calculations; with the modern standard pressure of one bar the value works out to about…
Read the full explanation →According to Graham's law, the rate of diffusion of a gas is inversely proportional to the
- A.Square of its molar mass
- B.Square root of its molar mass
- C.Cube root of its molar mass
- D.Absolute temperature
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Graham's law of diffusion states that at the same temperature and pressure the rate at which a gas diffuses is inversely proportional to the square root of its density, and therefore of its molar mass.
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