Physics

Thermodynamics and Gas Laws

626 Questions

Thermodynamics and gas laws questions test the understanding of ideal gas behavior, work done during thermodynamic processes, and specific heat ratios. Key areas include isothermal, adiabatic, and isobaric expansions along with real gas deviations. These mathematical physics concepts are standard in engineering and general science competitive exams.

Ideal gas equationIsothermal and adiabatic processesThermodynamic workGas kinetic theoryReal gas behavior

Thermodynamics and Gas Laws Questions

Multiple choice physics kinetic theory maxwell-boltzmann speed distribution function behavior of perfect gas and kinetic theory kinetic theory of matter

The average kinetic energy of a gas molecule at ${27}^{o}C$ is $6.21\times {10}^{-21}J$, then its average kinetic energy at ${227}^{o}C$ is:

  1. $10.35\times {10}^{-21}J$
  2. ${11.35}\times {10}^{-21}J$
  3. $52.2\times {10}^{-21}J$
  4. $5.22\times {10}^{-21}J$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Average kinetic energy of gas molecules $\propto$ Temperature (Absolute)
$\cfrac{K.E(at\quad {227}^{o}C)}{K.E (at\quad {27}^{o}C)}=\cfrac{273+227}{273+27}=\cfrac{500}{300}=\cfrac{5}{3}$
$K.E({227}^{o})=\cfrac{5}{3}\times 6.21\times {10}^{-21}J=10.35\times {10}^{-21}J$

Multiple choice physics kinetic theory maxwell-boltzmann speed distribution function behavior of perfect gas and kinetic theory kinetic theory of matter

For a given gas, which of the following relationships is correct at a given temp?

  1. $u _{rms} > u _{av} > u _{mp}$
  2. $u _{rms} < u _{av} < u _{mp}$
  3. $u _{rms} > u _{av} < u _{mp}$
  4. $u _{rms} < u _{av} > u _{mp}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$u _{rms} = $ Root mean square velocity
$u _{ar}= $Average velocity 
$u _{mp} $= Most probable velocity
$u _{mp}:u _{ar}:u _{rms}= 1: 1.128: 1224$
$\therefore u _{rms} > u _{ar} > u _{mp}$

Multiple choice chemistry chemical equilibrium relationship between equilibrium constant, reaction quotient and gibbs energy law of mass action chemical equilibrium and acids-bases

The value of $\Delta G^{\circ} _{r}$ of gaseous mercury is $31 kJ/mole$. At what external pressure mercury start boiling $25^{\circ}C$.

  1. $10^{-5.44}$
  2. $10^{-12.5}$
  3. $10^{-6.52}$
  4. $10^{-3.12}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The reaction occuring is
$Hg:(l)\rightleftharpoons G(g)$
$:\Delta G^{\circ}=31:kJ/mol$.
Since Boiling takes place, $K _p = P _{Hg}$.
Now, at boiling equilibrium exists. For equilibrium, we have the following equation,
$\Delta G^{\circ}=-RT:\ln :K _{P}$
$\Rightarrow 31\times 10^{3}=-8.31\times 298:\ln :K _{P}$
Solving, we get $P _{Hg} = K _p = 10^{-5.44} $

Multiple choice physics air, winds and cyclones the concept of bernoulli's principle air exerts pressure wind and pressure wind and rain uneven heating of earth

Why do two balloons come closer when we blow in the space between them ?

  1. Greater pressure inside the balloons than the reduced pressure in between them drives the balloons towards one another.

  2. Blowing air in between increases the pressure in between the balloons pulls them closer.

  3. The gravitational force pulls the two balloons closer.

  4. None of the above.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
When we blow between two balloons, they come closer because the pressure between the balloon decreases. The pressure inside the balloon would then push them towards each other.
Multiple choice fluid dynamics option b: engineering physics physics

Coefficient of viscosity of a gas:

  1. increases with increase of temperature.

  2. decreases with increase of temperature.

  3. remains constant with increase of temperature.

  4. may increase or decrease with increase of temperature.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

With increase in temperature, the molecule of gas carry more momentum and collide more often, that means more viscosity. So, coefficient of viscosity of a gas increases  with increase of temperature.

Multiple choice physics option a: relativity maxwell's equations the nature of light introduction to electromagnetic waves

In Maxwell's velocity distribution curve area under the graph 

  1. Increases when temperature is increased

  2. Deccreases when temperature is increased

  3. Remains same at all temperature

  4. Depends on the pressure of the gas
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Area under the Maxwell's velocity distribution curve gives the number of particles. Since number of particles remains the same at all the temperatures, so the area under the curve also remains the same at all temperature.

Multiple choice chemistry p- block elements-ii compounds of phosphorus - pcl3 phosphorus halides compounds of phosphorus compounds of phosphorus- pcl5

$\mathrm{B}$ottle of $\mathrm{P}\mathrm{C}l _{3}$ is kept stoppered because it :

  1. explodes

  2. gets oxidized

  3. is volatalised

  4. reacts with moisture
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Solution:-
$PCl _3+3H _2O\rightarrow H _3\ PO _3+3HCl$


$PCl _3$ reacts rapidly and exothermically with water to form phosphorus acid ,$H _3PO _3$ and $HCl$.

Option D is correct.

Multiple choice chemistry air and atmosphere carbon dioxide - an oxide of carbon component of air - carbon dioxide oxides of non metal

At temperatures and pressures above the critical point, carbon dioxide behaves as a:

  1. Semiconductor
  2. Supercritical $C{O} _{2}$
  3. $CO$

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

Supercritical carbon dioxide is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure. Carbon dioxide usually behaves as a gas in air at standard temperature and pressure (STP), or as a solid called dry ice when frozen. If the temperature and pressure are both increased from STP to be at or above the critical point for carbon dioxide, it can adopt properties midway between a gas and a liquid.

Multiple choice chemistry states of matter: gaseous and liquid states gay lussac's law gas laws states of matter

Which gas law should be used to solve a gas problem in which only the pressure and temperature of a gas change?

  1. Boyle's Law

  2. Ideal Gas Law

  3. Combined Gas Law

  4. Gay-Lussac's Law
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Gay-Lussac's law states that for a given mass and constant volume of  an ideal gas, the pressure exerted on the sides of container is directly propotional to  absolute temperature.

So, for pressure-temperature graph, we use Gay-Lussac's law.

Multiple choice chemistry states of matter: gaseous and liquid states gay lussac's law gas laws states of matter

A glass container is sealed with a gas at $0.800$ atm pressure and at $25^o$C. The glass container sustain pressure of $2$ atm. Calculate the temperature to which gas can be heated before bursting the container.

  1. $432^o$C.
  2. $472^o$C.
  3. $372^o$C.
  4. $572^o$C.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
We have,

 $p _1=0.8$atm$,p _2=2$atm $T _1=298$k

Thus,

According to the Gas equation,

$\dfrac{p _1}{T _1}=\dfrac{p _2}{T _2}$

$\dfrac{0.8}{298}=\dfrac{2}{T _2}$

$T _2=745$k

$=472^0$C

Hence, the correct option is $\text{B}$
Multiple choice chemistry states of matter: gaseous and liquid states gay lussac's law gas laws states of matter

The volume of a gas is held constant while its temperature is raised. The pressure of the gas exerts on the walls of the container increases because:

  1. The masses of the molecules increases

  2. Each molecule loses more kinetic energy when it strikes the wall

  3. The molecules collide with the wall with relatively greater momentum

  4. The molecules strikes the walls more often
Reveal answer Fill a bubble to check yourself
C,D Correct answer
Explanation

Volume is kept constant and temperature increased.
We have relation, $PV=nRT$
$P\propto T$
Volume constant
So, $P\propto T$ pressure increases as temperature increases.
As we know the speed or average molecular speed depend on temperature.
As temperature increases molecules collide with wall with greater force or momentum.
Also temperature increases, molecular vibrations increases. So molecule will strike with wall more often.
So option C and D.
A is incorrect because there is no change in masses of molecule when we increase temperature.