05 Gaseous State Quiz - Chemistry QuizIn this Gaseous state chemistry quiz section we are going to share Chemistry study material and some questions related following topics Characteristics and Measurable properties of gases, Ideal gas equation and Related gas laws, kinetic molecular theory of gases and Molecular collisions, Molecular speeds, Real gases and Vander Waal's equation, Critical state and Liquefaction of gases.
Gaseous StateThe state of matter in which the molecular forces of attraction between the particles of matter are minimum is known as the gaseous state. It is the simplest state and shows great uniformity in behaviour.
Characteristics of gases
(1) Gases or their mixtures are homogeneous in composition.
(2) Gases have very low density due to negligible intermolecular forces.
(3) Gases have infinite expansibility and high compressibility.
(4) Gases exert pressure.
(5) Gases possess high diffusibility.
(6) Gases do not have definite shape and volume like liquids.
(7) Gaseous molecules move very rapidly in all directions in a random manner i.e., gases have the highest kinetic energy.
(8) Gaseous molecules collide with one another and also with the walls of the container with perfectly elastic collisions.
(9) Gases can be liquified if subjected to low temperatures (below critical) or high pressures.
(10) Thermal energy of gases >> molecular attraction.
(11) Gases undergo similar change with the change of temperature and pressure. In other words, gases obey certain laws known as gas laws.
Characteristics and Measurable properties of gases Quiz1. Kinetic energy of molecules is highest in
SOL: (a) In gases, molecular attraction is very less and intermolecular spaces are large hence kinetic energy of gases is highest.
2. Which of the following statement is correct
(a) In all the three states the molecules possess random translational motion
(b) Gases cannot be converted into solids without passing through liquid state
(c) One of the common property of liquids and gases is viscosity
(d) According to Boyle's law V/P is constant at constant T
SOL: (c) Gases and liquids, both can flow and posses viscosity.
3. Which one of the following statements is wrong for gases
(a) Gases do not have a definite shape and volume
(b) Volume of the gas is equal to the volume of the container confining the gas
(c) Confined gas exerts uniform pressure on the walls of its container in all directions
(d) Mass of the gas cannot be determined by weighing a container in which it is enclosed
SOL: (d) The mass of gas can be determined by weighing the container, filled with gas and again weighing this container after removing the gas. The difference between the two weights gives the mass of the gas
Ideal gas equation and Related gas laws Quiz4. Air at sea level is dense. This is a practical application of
(a) Boyle's law
(b) Charle's law
(c) Avogadro's law
(d) Dalton's law
SOL: (a) At sea level, because of compression by air above the proximal layer of air, pressure increases hence volume decreases i.e. density increases. It is Boyle’s law.
5. Use of hot air balloons in sports and meteorological obsevations is an application of
(a) Boyle's law (b) Newtonic law
(c) Kelvin's law (d) Charle's law
6. Which of the following statement is false
(a) The product of pressure and volume of fixed amount of a gas is independent of temperature
(b) Molecules of different gases have the same K.E. at a given temperature
(c) The gas equation is not valid at high pressure and low temperature
(d) The gas constant per molecule is known as Boltzmann constant
SOL: (a) P.V = constant at constant temperature. As temperature changes, the value of constant also changes.
7. In the equation of sate of an ideal gas PV=nRT, the value of the universal gas constant would depend only on
(a) The nature of the gas
(b) The pressure of the gas
(c) The units of the measurement
(d) None of these
SOL: (c) The value of universal gas constant can be expressed in different units and its value would depend only on the units of the measurement.
8. Gas equation PV=nRT is obeyed by
(a) Only isothermal process
(b) Only adiabatic process
(c) Both (a) and (b)
(d) None of these
9. Rate of diffusion of a gas is
(a) Directly proportional to its density
(b) Directly proportional to its molecular mass
(c) Directly proportional to the square root of its molecular mass
(d) Inversely proportional to the square root of its molecular mass
10. At constant temperature and pressure which gas will diffuse first H2 or O2?
(c) Both will diffuse in same time
(d) None of the above
11. At NTP, the density of a gas, whose molecular weight is 45 is
(a) 44.8 gm/litre (b) 11.4 gm/litre
(c) 2 gm/ litre (d) 3 gm/litre
Kinetic molecular theory of gases and Molecular collisions Quiz
12. In deriving the kinetic gas equation, use is made of the root mean square velocity of the molecules because it is
(a) The average velocity of the molecules
(b) The most probable velocity of the molecules
(c) The square root of the average square velocity of the molecules
(d) The most accurate form in which velocity can be used in these calculations
(a) Molecular mass (b) Atomic mass
(c) Equivalent mass (d) None of these
SOL: (d) Kinetic energy 3/2RT
14. The kinetic theory of gases perdicts that total kinetic energy of a gaseous assembly depends on
(a) Pressure of the gas
(b) Temperature of the gas
(c) Volume of the gas
(d) Pressure, volume and temperature of the gas
SOL: (b) K.E = 3/2 RT it means that K.E depends upon T (absolute temperature) only.
15. Helium atom is two times heavier than a hydrogen molecule at 298 K, the average kinetic energy of helium is
(a) Two times that of a hydrogen molecule
(b) Same as that of a hydrogen molecule
(c) Four times that of a hydrogen molecule
(d) Half that of a hydrogen molecule
SOL: (b) energies will be same for H2 at same temperature.
16. Which of the following is valid at absolute zero
(a) Kinetic energy of the gas becomes zero but the molecular motion does not become zero
(b) Kinetic energy of the gas becomes zero and molecular motion also becomes zero
(c) Kinetic energy of the gas decreases but does not become zero
(d) None of the above
17. The average K.E. of an ideal gas in calories per mole is approximately equal to
(a) Three times the absolute temperature
(b) Absolute temperature
(c) Two times the absolute temperature
(d) 1.5 times the absolute temperature
18. With increase of pressure, the mean free path
(c) Does not change
(d) Becomes zero
SOL: (a) On increasing pressure, the volume decreases and density increases. So molecules get closer to each other hence mean free path also decreases.
19. Which one of the following statements is NOT true about the effect of an increase in temperature on the distribution of molecular speeds in a gas
(a) The most probable speed increases
(b) The fraction of the molecules with the most probable speed increases
(c) The distribution becomes broader
(d) The area under the distribution curve remains the same as under the lower temperature
SOL: (b) Most probable velocity increase and fraction of molecule possessing most probable velocity decrease.
20. The density of air is 0.00130 g/ml. The vapour density of air will be
(a) 0.00065 (b) 0.65
(c) 14.4816 (d) 14.56
21. Dimensions of pressure are the same as that of
(a) Energy (b) Force
(c) Energy per unit volume (d) Force per unit volume
SOL: (c) Energy per unit volume = P
22. Vibrational energy is
(a) Partially potential and partially kinetic
(b) Only potential
(c) Only kinetic
(d) None of the above
23. At the same temperature and pressure, which of the following gases will have the highest kinetic energy per mole
(a) Hydrogen (b) Oxygen
(c) Methane (d) All the same
SOL: (d) K.E. per mole = 3/2 RT
so all will have same K.E. at same temperature.
Molecular speeds Quiz
24. Consider a mixture of and kept at room temperature. Compared to the oxygen molecule, the molecule will hit the wall with
(a) Smaller average speed
(b) Greater average speed
(c) Greater kinetic energy
(d) Greater mass
25. The r.m.s. velocity of a certain gas is at 300K. The temperature, at which the r.m.s. velocity becomes double
(a) 1200K (b) 900K
(c) 600K (d) 200K
26. The r.m.s. velocity of a gas depends upon
(a) Temperature only
(b) Molecular mass only
(c) Temperature and molecular mass of gas
(d) None of these
27. Ratio of average to most probable velocity is
(a) 1.128 (b) 1.224
(c) 1.0 (d) 1.112
SOL: (a) Average speed : most probable speed
Real gases and Vander waal’s equation Quiz
28. The Vander Waal's equation reduces itself to the ideal gas equation at
(a) High pressure and low temperature
(b) Low pressure and low temperature
(c) Low pressure and high temperature
(d) High pressure and high temperature
29. The compressibility factor for an ideal gas is
(a) 1.5 (b) 1.0
(c) 2.0 (d)
30. When an ideal gas undergoes unrestrained expansion, no cooling occurs because the molecules
(a) Are above the inversion temperature
(b) Exert no attractive force on each other
(c) Do work equal to loss in kinetic energy
(d) Collide without loss of energy
SOL: (b)Ideal gas has no attractive force between the particles
31. When helium is allowed to expand into vacuum, heating effect is observed. Its reason is that
(a) Helium is an ideal gas
(b) Helium is an inert gas
(c) The inversion temperature of helium is very low
(d) The boiling point of helium is the lowest among the elements
32. In van der Waal’s equation of state of the gas law, the constant ‘b’ is a measure of
(a) Volume occupied by the molecules
(b) Intermolecular attraction
(c) Intermolecular repulsions
(d) Intermolecular collisions per unit volume
SOL: (a) Vander waal's constant for volume correction b is the measure of the effective volume occupied by the gas molecule.
Critical state and Liquefaction of gases Quiz
33. Adiabatic demagnetisation is a technique used for
(a) Adiabatic expansion of a gas
(b) Production of low temperature
(c) Production of high temperature
SOL: (b) A diabatic demagnetisation is a technique of liquefaction of gases in which temperature is reduced.
34. An ideal gas can't be liquefied because
(a) Its critical temperature is always above
(b) Its molecules are relatively smaller in size
(c) It solidifies before becoming a liquid
(d) Forces operative between its molecules are negligible
SOL: (d) An ideal gas can’t be liquefied because molecules of ideal gas have not force of attraction between them.
35. However great the pressure, a gas cannot be liquefied above its
(a) Boyle temperature
(b) Inversion temperature
(c) Critical temperature
(d) Room temperature
SOL:(c) At above critical temperature, substances are existing in gaseous state, since gas cannot be liquefied above it.
36. A gas can be liquefied
(a) Above its critical temperature
(b) At its critical temperature
(c) Below its critical temperature
(d) At any temperature
SOL: (c) The temperature below which the gas can be liquefied by the application of pressure alone is called critical temperature.
37. Which of the following is correct for critical temperature
(a) It is the highest temperature at which liquid and vapour can coexist
(b) Beyond the critical temperature, there is no distinction between the two phases and a gas cannot be liquefied by compression
(c) At critical temperature Tc the surface tension of the system is zero
(d) At critical temperature the gas and the liquid phases have different critical densities
38. The ratio of the rate of diffusion of helium and methane under identical condition of pressure and temperature will be
(a) 4 (b) 2
(c) 1 (d) 0.5
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