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 air and water pollution control smoke, dust and other air pollutants, acid rain air pollutants and its effects air and air pollution

What is concentration of hydrogen sulphide when inhaled will be safe?

  1. 10 ppm

  2. 100ppm

  3. 1000 ppm

  4. 2000 ppm
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For hydrogen sulfide, it is allowable for workers to be exposed to concentrations of 10 parts per million, averaged over an eight-hour work shift, with the exposure not exceeding 15 parts per million. 
1000ppm and 2000ppm have high probability of death and lose consciousness.

Multiple choice physics heat - measurement introduction to temperature application of various thermometric scales different types of thermometers

A liter of air at $20^oC$ is heated until both the pressure and the volume are tripled, what is the tempertare then.

  1. $2637^oK$
  2. $927^oK$
  3. $200^oK$
  4. $977^oK$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Applying the formula

$PV=nRT$
$\dfrac { { P } _{ 1 } }{ { V } _{ 1 } } =\dfrac { { P } _{ 2 } }{ { V } _{ 2 } } =\dfrac { { T } _{ 1 } }{ { T } _{ 2 } } $    [$R$ is constant]
Let ${ P } _{ 1 }=P$  and ${ V } _{ 1 }=V$
As given ${ P } _{ 2 }=3P$   ${ V } _{ 2 }=3V$
${ T } _{ 1 }={ 20 }^{ 0 }C=20+2+3=293$
${ T } _{ 2 }=?$
$\dfrac { PV }{ 3P\times 3V } =\dfrac { 293 }{ { T } _{ 2 } } $
$\dfrac { 1 }{ 9 } =\dfrac { 293 }{ { T } _{ 2 } } $
${ T } _{ 2 }=293\times 9=2637$
$\therefore$    New temperature $=2637$.

Multiple choice physics the kinetic model of matter gases and the kinetic theory concept of ideal gas and state equation of ideal gas behaviour of perfect gas and kinetic theory of gases

1 litre of oxygen at a pressure of 1 atmosphere and 2 litres of nitrogen at a pressure of 0.5 atmosphere are introduced in a vessel of 1 litre capacity without any change in temperature. The total pressure in atmosphere is

  1. 1

  2. 2

  3. 3

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

In this case, Initial pressure of oxygen $=$ 1 atm and initial volume of oxygen $=$ 1 lit
Initial pressure of nitrogen $=$ 0.5 atm and inititial volume of nitrogen $=$ 2 lit
Since temperature is constant, pressure (P) and volume (V) of the combined gas will be
$PV = P _{oxygen}V _{oxygen} + P _{nitrogen}V _{nitrogen}$
Given, volume of combined gas $=$ 1 lit.
${P}{(1)}={(1)}{(1)}+{(0.5)}{(2)}$
${P} ={2}$ atm
Putting all these values we get pressure of the combined gas $=$ 2 atm

Multiple choice physics the kinetic model of matter gases and the kinetic theory concept of ideal gas and state equation of ideal gas behaviour of perfect gas and kinetic theory of gases

An ideal gas is trapped between Hg thread of $12\ cm$ and the closed lower end of a narrow vertical tube of uniform cross section. Length of the air column is $20.5\ cm$, when the open end is kept upward. If the tube is making $30^{0}$with the horizontal then the length of the air column is (assuming temperature to be constant and atmospheric pressure = $76\ cm$ of $Hg$) 

  1. $22\ cm$
  2. $18\ cm
  3. $24\ cm$
  4. $20.2\ cm$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Assuming the process to be isothermal, we can sa for an ideal gas,


${ P } _{ 1 }{ V } _{ 1 }={ P } _{ 2 }{ V } _{ 2 }$

$(76+12)(20.5)=(76+12sin({ 30 }^{ 0 }))l$, since in second case, the vertical height of mercury column will be $12sin({ 30 }^{ 0 })$.

This gives $l=22cm$.

Multiple choice common laboratory equipments common laboratory apparatus and equipments laboratory equipments know about some common gases chemistry

Two identical containers are filled with gas. The first container is filled neon and the second with krypton. Both containers are placed at NTP conditions.
Which of the following factors will NOT be equal for the two containers?

  1. Number of particles

  2. Kinetic Energy

  3. Pressure

  4. Masses

  5. Number of moles
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Two identical containers are when filled with gas, one with $Ne$ and one with $Kr$ and are then placed at $NTP$. They will be present at same conditions of temperature and pressure.

Also, their volume will be same, since they occupy identical containers but their number of particles would be different.  

Multiple choice chemistry the particle theory atmospheric pressure and boiling point evaporation - factors and effects in daily life changes in physical state - boiling, evaporation and condensation

Which of the following is not the unit of atmosperhic pressure?

  1. $Pascal$
  2. $N/m^2$
  3. $N/m$
  4. $76\ cm\ of\ Hg$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The unit of the pressure is $pascal$. $N/m^2$, and $76\ cm\ of\ Hg$.

Here $N/m$ is the unit of the surface tension. 
Thus option C is the correct answer.

Multiple choice chemistry the particle theory atmospheric pressure and boiling point evaporation - factors and effects in daily life changes in physical state - boiling, evaporation and condensation

Usually the atmospheric pressure is equal to ___________.

  1. $1.013\times 10^{5}$ Pascal
  2. $1.013\times10^{5}N/m^2$
  3. $101.3\ kPa$

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The atmospheric pressure can be given as $1.013\times 10^{5}\ pascals$ or $1.013\times10^{5}\ N/m^2$.

Multiple choice chemistry separation of substances classification of mixtures mixtures: examples and properties types of solutions

$3$ litre of mixture of propane $(C {3}H _{8})$ $ butane $(C{4}H_{10})$ on complete combustion gives $10$ litre $CO_{2}$. Find the composition of mixture.

  1. $C _{3}H _{8}2L$ and $C _{4}H _{10}\ 1L$
  2. $C _{3}H _{8}3L$ and $C _{4}H _{10}\ 0L$
  3. $C _{3}H _{8}\ 1.5L$ and $C _{4}H _{10}\ 1.5L$
  4. $C _{3}H _{8}\ 0L$ and $C _{4}H _{10}\ 3L$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let x be the volume of propane and y be the volume of butane. We have x + y = 3. The combustion reactions are C3H8 + 5O2 -> 3CO2 + 4H2O and C4H10 + 6.5O2 -> 4CO2 + 5H2O. Thus, 3x + 4y = 10. Solving these equations gives x = 2 and y = 1.

Multiple choice evs - i life is precious road safety and pollution pollution of natural resources air pollution and its effects

Level of atmospheric $CO _2$ has increased in $2000$ from

  1. $280$ ppm to $360$ ppm
  2. $250$ ppm to $300$ ppm
  3. $300$ ppm to $340$ ppm
  4. $330$ ppm to $350$ ppm
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Carbon dioxide is the greenhouse gas. It means that it traps the insolation from the sun and does not allow them to be reflected back. The trapped insolation work in warming the overall temperature of the earth. The level of atmospheric CO$ _{2}$ was around 200 ppm during the ice age. It rose to 280 ppm during the warmer interglacial periods. Presently, in the Anthropocene era, due to the excessive CO$ _{2}$ releasing activities like fossil fuel burning, the level of CO$ _{2}$ has risen to 360 ppm.

Hence, the correct answer is '280 ppm to 360 ppm'

Multiple choice chemistry basic concepts of chemistry law of multiple proportion law of multiple proportions laws of chemical combination

The ratio between the different weights of oxygen in different compounds which combine with the same weight of nitrogen ($14$ parts) is $8:16:24:32:40$ or $1:2:3:4:5$.
This is simple whole number which supports the law of:

  1. conservation of mass

  2. multiple proportion

  3. constant composition

  4. reciprocal proportion
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The answer is multiple proportion.
When two elements combine to from two or more than two compounds, the weights of one of the element which combine with a fixed weight of the other, bear a simple whole number ratio is the law of multiple proportion and the given example supports the law.

Multiple choice chemistry basic concepts of chemistry law of multiple proportion law of multiple proportions laws of chemical combination

0.75 mole of solid ‘$A _4$’ and 2 moles of gaseous $O _2$ are heated in a sealed vessel, completely using up the reactants and producing only one compound. It is found that when the temperature is reduced to the initial temperature, the contents of the vessel exhibit a pressure equal to half the original pressure. What conclusions can be drawn from these data the product of the reaction?

  1. $A _2O _5$
  2. $A _3O _4$
  3. $A _2O _2$

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
give reaction
$A _4(s) + O _2(g) → A _xO _y$

Applying POAC  law for A atoms,
4 × moles of $A _4  =  x \times moles of A _xO _y$
=> $4 \times 0.75 = x \times  1$
=> x = 3

Applying POAC for O atoms,
$2\times  moles of O _2 = y \times moles of A _xO _y$
=> $2 \times 2 = y \times 1$
=> y = 4

Thus, the formula of the product is $A _3O _4$.
Multiple choice chemistry basic concepts of chemistry law of multiple proportion law of multiple proportions laws of chemical combination

Carbon and oxygen combine to form two oxides, carbon monoxide and carbon dioxide in which the ratio of the weights of carbon and oxygen is respectively 12 : 16 and 12 : 32. These figures illustrate the:

  1. Law of multiple proportions

  2. Law of reciprocal proportions

  3. Law of conservation of mass

  4. Law of constant proportions
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
When two elements combine to form two or more chemical compounds, then the masses of one of the elements which combined with a fixed mass of the other, bear a simple ratio to one another. For eg, Carbon combines with oxygen to form two compounds namely carbon dioxide and carbon monoxide.

In carbon dioxide, 12 parts by mass of carbon combine with 32 parts by mass of oxygen while in carbon monoxide, 12 parts by mass of carbon combine with 16 parts by mass of oxygen. The masses of oxygen which combined with a fixed mass of carbon in carbon monoxide and carbon dioxide are 16 and 32. These masses of oxygen bear a simple ratio of 16:32 or 1:2 to each other.

Hence, the correct option is $A$.
Multiple choice chemistry basic concepts of chemistry law of multiple proportion law of multiple proportions laws of chemical combination

100 ml of hydrogen combine with 50 ml of oxygen to give 100 ml of water vapour. This statement is according to:

  1. Law of multiple proportions

  2. Gay Lussac's law

  3. Avagadro's law

  4. Dalton's atomic theory
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Law of multiple proportions states that, when two elements combine to form more than one compound, the weights of the combining elements are in a ratio of small whole numbers.


Here, the hydrogen and oxygen combine in a ratio of $2:1$


So it is according to the law of multiple proportions and the correct answer is ( A )