250+ TOP MCQs on States of Matter – Gaseous State and Answers

Chemistry Multiple Choice Questions on “States of Matter – Gaseous State”.

1. What is the lowermost layer of the earth?
a) stratosphere
b) troposphere
c) ionosphere
d) mesosphere
Answer: b
Clarification: It is the lowest layer of the earth’s atmosphere and is held to the earth by the gravitational force. It is very vital for human life and it protects us from harmful radiation. It contains important molecules like dioxygen, carbon dioxide, water vapor, etc.

2. Which of the following statement is true regarding gases?
a) gases are highly incompressible
b) gases exert equal pressure on each and every direction
c) its volume and shape is fixed
d) gases have the highest density among the 3 States of matter
Answer: b
Clarification: The correct statement is that gases exert equal pressure on each and every direction. Among the given options the corrected statements of other options are that gases are highly compressible, they occupy the shape and volume of the container as they have no fixed shape and volume and also that they have the least density among the three states of matter.

3. Which of the following element is not a gas?
a) Hydrogen
b) Oxygen
c) Mercury
d) Nitrogen
Answer: c
Clarification: Mercury is not a gas, it is a liquid in room temperature and it is a metal. There are 11 gases which are gases at room temperature they are hydrogen, Nitrogen, Oxygen, fluorine, chlorine, Helium, Neon, Argon, Krypton, Xenon, and Radon.

4. Gases have low density than that of solids and liquids because of __________
a) no thermal energy
b) higher intermolecular energy
c) both intermolecular energy and thermal energy are the same
d) higher thermal energy
Answer: d
Clarification: In gases, there is less amount of intermolecular energy and higher amount of thermal energy. As we know that thermal energy separates some molecules from one another so gases have low density than that of solids and liquids.

5. Gases mix properly without any mechanical aid.
a) true
b) false
Answer: a
Clarification: As the forces of interaction between molecules of a gas is negligible when compared with solids and gases. They mix properly because of higher thermal energy and lower intermolecular energy, so the above statement is true.

6. Which of the following is not a gas law?
a) Boyle’s law
b) Charles law
c) Hooks law
d) Gay lussac’s law
Answer: c
Clarification: Boyle’s law is about the relationship between pressure and volume while Charles law about temperature and volume. Gay lussac’s law is about pressure-temperature relationship & hooks law is a law that is in Physics relating to stress.

7. What is the percentage of Nitrogen in the atmosphere approximately?
a) 78.09
b) 21
c) 20
d) 32
Answer: a
Clarification: That composition of earth’s atmospheric gases is as follows; 78.09 percent of Nitrogen, 24.95 percent of oxygen, 0.93 percent of argon, 0.04 percentage of carbon dioxide and a small amount of water vapor and other gases in the atmosphere.

8. What can you say about particles motion in gases?
a) only vibratory
b) very slow
c) both vibratory and irregular
d) too Rapid and random
Answer: d
Clarification: A particle’s motion in the gaseous state is too rapid and random while in solids it’s restricted to vibratory motion and in liquids, it’s very slow. This is one of the very basic properties of substances in the gaseous state.

9. How many moles of oxygen are present in 64 grams of oxygen?
a) three moles
b) two moles
c) one mole
d) 16 moles
Answer: b
Clarification: As we know that the number of moles of a gas is given by the amount of the substance in weight divided by the molecular weight of the substance. So in case of oxygen, it is 64 grams divided by 32 grams and that is two moles.

10. At STP conditions how much volume does one mole of a gas comprise of _________
a) 22.4 liters
b) 24 liters
c) depends on the molecular weight of the gas
d) depends on some other conditions
Answer: a
Clarification: Every one Mole of gas at STP consists of 22.4 liters of volume, that is at 0° Celsius of temperature and one-atmosphere pressure or 76 mm of Mercury pressure. Also, note that one mole of a gas is the amount of gas in weight divided by the molecular weight of the gas.

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