Chemistry · Physics

Gases and Gas Laws

298 Questions

The study of gases and gas laws involves understanding the relationships between pressure, volume, and temperature of gases. This topic is essential for chemistry and physics sections in many competitive exams. Practice these questions to master concepts like the ideal gas law, partial pressure, and molecular properties.

Ideal gas law calculationsGas volume and pressureStoichiometry of gasesDensity of gasesBoltzmann constant applicationsThermal speed of sound

Gases and Gas Laws Questions

Multiple choice chemistry energy rocks and minerals petroleum and natural gas fossil fuels

The octane number of gasoline is defined as the percentage of n-heptane present in a mixture of iso-octane and n-heptane, when the mixture has the same knocking in the engine, as the gasoline under examination.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The octane number of gasoline is defined as the percentage of iso-octane present in a mixture of iso-octane and n-heptane, when the mixture has the same knocking in the engine, as the gasoline under examination.

Multiple choice chemistry energy rocks and minerals petroleum and natural gas fossil fuels

As per the EuroIII norms for gasoline the benzene content should be:

  1. 1%

  2. 2%

  3. 3%

  4. 4%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Bharat stage emission standard is an emission standard institute which is governed by the government of India to regulate the air pollutants from internal combustion engines or vehicle motors.Bharat Stage III norms or Euro III norms were enforced in October 2010 all over the country. According to this benzene content in gasoline should be 1%.

Multiple choice chemistry energy rocks and minerals petroleum and natural gas fossil fuels

The RON/MON value of iso-octane is:

  1. $0$
  2. $100$
  3. $50$
  4. $1000$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Octane number can be determined by RON, MON and AKI. The most common method used for the measurement is RON. RON is determined by running the fuel in a test engine and comparing the results with those for mixtures of iso-octane and $n$- heptane. The RON/MON values of iso-octane is 100.

Multiple choice chemistry energy rocks and minerals petroleum and natural gas fossil fuels

The petrol, octance number of which is $80$, has:

  1. $20\%$ n - heptane + $80\%$ iso-octane
  2. $20\%$ n - heptane + $80\%$ n-octane
  3. $80\%$ n - heptane + $20\%$ iso-octane
  4. $80\%$ n - heptane + $20\%$ n-octane
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Petrol, which has octane number 80 contain 20% n-heptane and 80% iso-octane.

Multiple choice chemistry energy rocks and minerals petroleum and natural gas fossil fuels

$90-$ Octane Petrol is a rating that indicates that the petrol in the engine would not waster its energy in making a 'knocking sound', but would rather use its energy efficiency to maintaining speed for travel $'90-Octane$ petrol' means that the petrol is as good as:

  1. $90$% octane
  2. $90$% normal heptane and $10$% iso-octane
  3. A mixture of $90$% iso-octane and $10$% normal (straight chain) heptane
  4. $90$% petrol
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

90-Octane petrol is the  mixture of 90% iso-octane and 10% normal (straight chain) heptane.

Hence option C is correct.

Multiple choice evs atmosphere- wind weather, climate and adaptation of animals to different climates climate and weather weather, climate and adaptations of animals to climate

The $CO _{2}$ content by volume, in the atmospheric air is about

  1. 3.34%

  2. 4%

  3. 0.0314%

  4. 2.1%.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The carbon dioxide present in the atmosphere is generally the result of respiration by animals during the day and the emissions by various vehicles, industries and machines. All these activities account for a total of approximately 0.04% CO2 in the atmospheric air.

So, the correct answer is '0.0314%'.

Multiple choice chemistry chemical kinetics dependence of reaction rate on concentration of reactants order of reactions factors influencing rate of a reaction

A gaseous reaction, $A _{2}\left ( g \right )\rightarrow B\left ( g \right )+\frac{1}{2}\left ( g \right )$ 
Show increase in pressure from 40 mm to 120 mm in 5 minutes. the rate of disappearance of$A _{2}$ is ?

  1. 4 mm $min ^{-1}$
  2. 8mm $min^{-1}$
  3. 16 mm $min^{-1}$
  4. 2 mm $min^{-1}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Multiple choice chemistry chemical kinetics dependence of reaction rate on concentration of reactants order of reactions factors influencing rate of a reaction

A 22.4 litre flask contains 0.76 mm of ozone at $25^oC$. Calculate:
(i) the concentration of oxygen atom needed so that the reaction, $O+O _3\rightarrow 2O _2$ having rate constant equal to $1.5\times 10^7$ litre $mol^{-1} sec^{-1}$ can proceed with a rate of 0.15 mol $litre^{-1} sec^{-1}$
(ii) the rate of formation of oxygen under this condition.

  1. (i) $2.45\times 10^{-4}$, (ii) $0.30 mol L^{-1} t^{-1}$
  2. (i) $4.9\times 10^{-4}$, (ii) $0.60 mol L^{-1} t^{-1}$
  3. (i) $2.45\times 10^{-5}$, (ii) $0.30 mol L^{-1} t^{-1}$

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$\displaystyle [O _3] = \frac {P}{RT} = \frac {0.76}{760 \times 0.0821 \times 298} = 4.08 \times 10^{-5} $
$\displaystyle [O] = \frac {rate}{k \times [O _3]} = \frac {0.15}{1.5 \times 10^{7} \times 4.08 \times 10^{-5} = 2.45 \times 10^{-4}  }$
The rate of formation of oxygen under this condition is equal to twice the rate of the reaction.
It is equal to $\displaystyle 2 \times 0.15 : mol litre^{-1} sec^{-1} = 0.30 : mol litre^{-1} sec^{-1} $

Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

22.4 litres of a gas at STP weighs 16 g. Identify the gas.

  1. Methane

  2. Carbon monoxide

  3. Ethane

  4. Oxygen
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

At STP,  1 mole of gas occupies $22.4l$.

Given gas occupies $22.4l$ at STP and has weight 16 g.
So molecular weight of gas is 16. 
Thus Ans: Methane (Mol. weight of methane is 16)

Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

What is the volume occupied by 17.75 g of $Cl _2$ at STP?

  1. $5.6l$
  2. $22.4l$
  3. $11.2l$
  4. $2.8l$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In order to solve this problem, we would use the ideal gas law formula PV = nRT 

at STP standard temp and pressure is 1 atm and 273k

we have 

P = 1atm, n = $\dfrac{17.75}{70.90}$ mole = 0.250, R = $0.0821$ $atm*L/mol*K$ , T=$273K$

V = $\dfrac {nRT}{P}$

= $0.250\times 0.0821\times 273$

= $5.6L$

answer is A


Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

Two gases A and B are taken in same volume containers under similar conditions of temperature and pressure. In container A, there are '2N' molecules of gas A. How many number molecules does container B have? 

  1. 2N

  2. 4N

  3. N

  4. 8N
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Avogadro's law: Equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.

Thus ans is 2N.

Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

Assuming that the all volume is measured at the same temperature and pressure, state the volume ratios of the reactants and products for the following gaseous reactions. Nitrogen reacting with oxygen to form nitrogen (III) oxide.

  1. 1 : 3 : 2

  2. 2 : 4 : 2

  3. 2 : 2: 1

  4. 2 : 3 : 2
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The equation for the reaction between nitrogen and oxygen to form Nitrogen (lll) oxide is written as:
$2N _{2} + 3O _{2} \rightarrow 2N _{2}O _{3}$
Therefore the volume ratio of reactants and products $= 2 : 3 : 2$