Gases MCQs with Answers
At constant temperature, when the pressure of an ideal gas is increased three times, its volume becomes:
Under what conditions will the density of an ideal gas be maximum?
High temperature and low pressure
Low temperature and high pressure
Low temperature and low pressure
When temperature and pressure are the same
If 1/V is plotted on the X-axis and pressure (P) on the Y-axis at constant temperature, the graph should appear as:
Straight line parallel to x-axis
Straight line parallel to y-axis
Straight line passing through the origin
Curve
The general gas equation used to determine the volume of a gas at different temperatures is:
V₀ = 273Vₜ /(273+t)
V₀ = Vₜ / [1-(t/273 )]
Vₜ = V₀ / [1+(t/273 )]
None of these
A mono-atomic substance can store energy only in the form of:
Translational motion
Rotational motion
Vibrational motion
Rotational and vibrational motion
A graph between pressure (P) and the product of pressure and volume (PV) at constant temperature and number of moles is:
Straight line parallel to x-axis
Straight line parallel to y-axis
Straight line passing through the origin
A curve showing a maximum
If both the temperature and volume of a gas are doubled, what happens to its pressure?
Cannot be predicted
Remains unchanged
Is reduced to half
Is doubled
Which of the following represents the general gas equation?
PV=nRT
P.V=RT
PV/T=R
All of these
A gas occupies a volume of 10 dm³ at STP. At what temperature (keeping pressure constant) will its volume become 30 dm³?
Which of the following pairs of gases possess equal volume at STP?
44g CO₂ and 44g CO
16g O₂ and 32g CH₄
3.01 × 10²³ molecules of CO and 3.01 × 10²³ gram molecules of H₂
0.5 mole of NO and 16 g O₂
Which of the following is incorrect about an ideal gas?
No force of attraction between molecules
No example in nature
Can be liquefied easily
Obeys gas laws at all conditions of temperature and pressure
A gas initially at 27°C is heated up to 327°C. Its average kinetic energy will be:
Doubled
Four times
300 times
327 times
The correct value of the general gas constant R is:
8.314 atm dm³ mol⁻¹ K⁻¹
0.0821 J mol⁻¹ K⁻¹
62.4 torr cm³ mol⁻¹ K⁻¹
8.314×10 7 erg mol⁻¹K⁻¹
In gases and liquids, temperature is the measure of the kinetic energies of molecules:
Average translational
Rotational
Vibrational
All of these
The molar volume of nitrogen gas is maximum at:
25°C and 1 atm
0°C and 2 atm
130°C and 1 atm
100°C and 2 atm
8g of methane and 2g of hydrogen are mixed and kept at 760 mm pressure at 273 K. The total volume occupied by the mixture will be:
11.2 dm³
22.4 dm³
33.6 dm³
44.8 dm³
Which of the following is NOT true about gases?
They are highly compressible
They have only vibrational motion
Sudden expansion of gases causes cooling
They exert pressure on the walls of the vessel
For a definite mass of an ideal gas at constant temperature, the plot of which pair of variables will give a curved graph?
PV vs P
P vs V
P vs V⁻¹
PV vs P⁻¹
A pressure of 0.101325 bar when expressed in atmosphere represents:
0.01 atm
1.0 atm
0.1 atm
10.0 atm
The dimensions of pressure are the same as that of:
Energy
Force
Energy per unit volume
Force per unit volume
Gases deviate from ideal behavior at high pressure. Which of the following is correct for non-ideality?
At high pressure, the gas molecules move in one direction only
At high pressure, the collisions between gas molecules increase manifold
At high pressure, the volume of the gas becomes insignificant
At high pressure, the intermolecular attractions become significant
Under high pressure, which of the following gases shows more ideality in character?
When 200 cm³ of a gas at constant pressure is heated, its volume:
Increases
Remains unchanged
Decreases
First increases, then decreases
The product of PV of a gas has the unit of:
Under what conditions of temperature and pressure will a real gas behave most like an ideal gas?
Low temperature and low pressure
Standard temperature and standard pressure
Low temperature and high pressure
High temperature and low pressure
The absolute temperature of a gas is directly proportional to its average:
Rotational kinetic energy
Translational kinetic energy
Vibrational kinetic energy
None of these
An ideal gas cannot be liquefied because:
Its critical temperature is always above 0°C
It solidifies before becoming a liquid
Its molecules are smaller in size
Forces between its molecules are negligible
The compressibility factor (Z) for an ideal gas is:
Zero
Less than one
Greater than one
Equal to one
The numerical value of the general gas constant (R) in dm³ atm K⁻¹ mol⁻¹ is:
In a closed flask of one dm³, 2.0 g of hydrogen gas is heated from 27°C to 327°C. Which of the following is incorrect?
The pressure of the gas increases
The kinetic energy of gas molecules increases
The rate of molecular collisions increases
The number of moles of the gas increases
The pressure of a gas is due to:
Rapid intermolecular collisions
Molecular impacts against the walls of vessel
Voids between the gas molecules
Ideal gas behavior
The compressibility factor (Z), which measures the deviation of a real gas from ideal behavior, is given by (for one mole):
Z = PV/RT
Z = RT/PV
Z = RT^2/PV
Z = P/RT
Which of the following gases has the lowest root mean square (r.m.s) velocity at 25°C?
The critical temperature of different gases depends upon:
Size of the molecule
Shape of the molecule
Intermolecular attractions
All of the above
In Van der Waal's equation for real gases, the term "a" represents the coefficient of attraction. What is its unit?
Nm⁻⁴ mol⁻²
Nm mol⁻²
Nm⁴ mol⁻²
Nm² mol⁻²
The highest temperature at which a substance can exist as a liquid is called its:
Critical temperature
Standard temperature
Absolute temperature
Upper consulate temperature
Very small values of Van der Waal’s constant (a) for a particular gas indicate:
The molecules of the gas are large in size
The gas is sufficiently polar
The gas molecules have least attractive forces
The gases are non-ideal
The excluded volume in Van der Waal’s equation is how many times the actual volume of gas molecules?
The Van der Waal’s constant (a) is maximum for which gas?
Helium
Hydrogen
Oxygen
Ammonia
The average kinetic energy of gas molecules is:
Inversely proportional to its absolute temperature
Directly proportional to its absolute temperature
Equal to the square of its absolute temperature
Directly proportional to the square root of its absolute temperature
In gases, all collisions between particles are elastic. What does "Elastic Collisions" mean? (MDCAT 2013)
The velocity of the molecules changes
No change in mass during the collisions
No change in kinetic energy
No change in potential energy during the collisions
Which one of the following expressions represents Avogadro’s Law? (MDCAT 2010)
V=RnT/P (When T and n are constant)
V=RnT/P (When T and P are constant)
V= RnT/P (When P and n are constant)
V=RP/nT (When T, P, and n are constant)
The root mean square (r.m.s) velocity of gas molecules is inversely proportional to the square root of its: (MDCAT 2010)
Temperature
Pressure
Molar mass
Volume
The number of molecules in 22.4 dm³ of H₂ gas at 0°C and 1 atm is: (MDCAT 2012)
6.02 × 10²³
6.02 × 10²⁵
60.2 × 10²³
6.02 × 10²²
Four gases (H₂, He, N₂, and CO₂) are at 0°C. Which gas shows greater non-ideal behavior? (MDCAT 2013)
Identify the value of the gas constant (R) in atm dm³ mol⁻¹ K⁻¹: (MDCAT 2017)
In the Van der Waal’s equation, What does the term "b" represent? (MDCAT 2017)
Excluded volume
Excluded pressure
Actual volume
Excluded volume per mole
A gas is enclosed in a 20 cm³ container with a moving piston. According to the kinetic theory of gases, what happens to the freely moving molecules if the temperature increases from 20°C to 100°C? (MDCAT 2018)
Colliding capability of molecules will become lower
Pressure will become one half
Temperature has no effect on freely moving molecules
Volume will be increased
Which of the following is the correct equation to calculate relative molecular mass of a gas? (MDCAT 2018)
M= mPRT/V
M= mPR/VT
M= PV/mRT
M= mRT/PV
Which of the following statements is applicable to both ideal and real gas molecules? (SET 2019)
Have no forces of attraction
Collisions between molecules are elastic
Molecules are in random motion
The actual volume of gas is negligible compared to the volume of the container
At absolute zero, the molecules of hydrogen gas will have: (MDCAT 2019)
Only translational motion
Only vibrational motion
Only rotational motion
All motion ceases
According to the general gas equation, the density of an ideal gas depends on: (NMDCAT 2020)
Pressure
Temperature
Molar mass of the gas
All of the above
The actual volume of gas molecules is considered negligible at which of the following pressures? (NMDCAT 2020 / ETEA 2016)
Other Chemistry Topics MCQs
We have also prepared the following set of MCQsfor your Entry test preparation in quick way like MDCAT, ECAT and Armed forces test. WE WISH YOU BEST OF LUCK!