Chemistry · Physics

Gases and Gas Laws

252 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 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 separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

In a box with a semi-permeable membrane containing a mixture of two gases

  1. The heavier molecules will pass out of the container more rapidly than the lighter molecules

  2. The lighter molecules will pass out of the container more rapidly than the heavier molecules

  3. Both heavier and lighter pass out of the container at equal rates

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

In a box with a semi-permeable membrane containing a mixture of two gases, the lighter molecules will pass out of the container more rapidly than the heavier molecules. The gas leaving the container is somewhat enriched in the lighter molecules, while the residual gas is somewhat depleted. 

Multiple choice separation of components of mixtures methods of separation elements, compounds and mixtures chemistry

In a box with a semi-permeable membrane containing a mixture of two gases, the _____________ will pass out of the container more rapidly.

  1. Lighter molecules

  2. Heavy molecules

  3. All molecules equally

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

Gaseous diffusion is based on Graham's law, which states that the rate of effusion of a gas is inversely proportional to the square root of its molecular mass. For example, in a box with a semipermeable membrane containing a mixture of two gases, the lighter molecules will pass out of the container more rapidly than the heavier.

Multiple choice various types of barometer fluids physics

A thin tube of uniform cross - section is sealed at both ends. It lies horizontally, the middle $5 \,cm$ containing mercury and the two equal ends containing air at the same pressure P. When the tube is held at an angle $60^o$ with the vertical, the lengths of the air column above and below the mercury are $46$ and $44.5$ cm respectively. Calculate the pressure P, in cm of Hg. (The temperature of the system is kept at $30$ K)

  1. $92.5$ cm of Hg
  2. $75.4$ cm of Hg
  3. $73.0$ cm of Hg
  4. $70.5$ cm of Hg
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Using the ideal gas law PV=nRT and the condition that the mercury column is in equilibrium, the pressure P can be determined by balancing forces at the given angle. The change in air column lengths due to the shift in mercury position allows for solving the system of equations for P. The calculated value aligns with 75.4 cm of Hg.

Multiple choice evs let's play with water law of constant proportion - i law of constant proportion law of definite proportions

If a mixture containing 3 moles of hydrogen and 1 mole of nitrogen is converted completely into ammonia, the ratio of initial and final volumes under the same temperature and pressure would be:

  1. 3 : 1

  2. 1 : 3

  3. 2 : 1

  4. 1 : 2
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

3 moles of hydrogen and 1 mole of nitrogen is convened completely into ammonia.

$3H _2+N _2\rightarrow 2NH _3$

Hence option C is correct.

So 4 volumes of reactants (3+1) and 2 volumes of products that is the ratio of initial and final is 2:1

Multiple choice evs let's play with water law of constant proportion - i law of constant proportion law of definite proportions

The volume of oxygen at NTP evolved when 1.70 g of sodium nitrate is heated to a constant mass is: 

  1. 0.112 litre

  2. 0224 litre

  3. 22.4 litre

  4. 11.2 litre
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The chemical equation is:

$2NaNO _3(s)→  2NaNO _2 (s)+ O _2(g)$

2 moles of NaNO$ _3$ give one mole of Oxygen/22.4 L oxygen at STP

weight of NaNO$ _3$ = 85g

2 moles of NaNO$ _3$ weigh = 2(23+14+48) = 170g

170 g of NaNO$ _3$ will produce 22.4 L Oxygen at STP

​1.70 g will produce $= \cfrac{1.70}{170}×22.4 =0.224$ litres

Hence, the correct option is $\text{B}$
Multiple choice evs let's play with water law of constant proportion - i law of constant proportion law of definite proportions

At NTP, 10 litre of hydrogen sulphide gas reacted with 10 litre of sulphur dioxide gas. The volume of gas, after the reaction is complete, would be:

  1. 5 litre

  2. 10 litre

  3. 15 litre

  4. 20 litre
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$2H _2S+SO2\rightarrow 2H _2O+3S$

According to the equation $2\times 22.4 $ litre of  $H _2S$ gas reacts with $22.4$ litre of $SO _2$
So $5$ litre of $H _2S$ reacts with $10$ litre of $SO _2$
Hence option $A$ is correct.

Multiple choice biology natural disasters: winds, storms and cyclones composition of air introduction to air natural resources - air

The proportion of nitrogen in the open air is:

  1. $21$% by volume
  2. $50$% by weight
  3. $21$% by weight
  4. $78$% by volume
  5. $29$% by volume
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The proportion of nitrogen in the open air is 78% by volume.
Note:
Air is a mixture of gases. The volume percent of nitrogen and oxygen are 78%and 21% respectively. Air also contains tiny amounts of carbon dioxide, argon, methane, ozone and water vapour.

Multiple choice physics pressure common consequences of the atmospheric pressure atmospheric pressure and its consequences important points about atmospheric pressure

What is the mass of $2$ litres of nitrogen at $22.4$ atmospheric pressure and $273\ K$ 

  1. $28\ g$
  2. $14 \times 22.4 g$
  3. $56\ g$
  4. $none\ of\ these$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Consider STP conditions:
 
1) 1 mol = 22.4 L of gas; 1 mol of Nitrogen gas = 14 g
 
2) Therefore, 22.4 L Nitrogen gas = 14 g → 2 L Nitrogen = 1.25 g
 

3) This is at a standard pressure of 1 atm. So, 22.4 atm pressure corresponds to 22.4 × 1.25 = 28 g