Questions tagged [kinetic-theory-of-gases]

Questions about the assumptions, equations, and properties of gases derived from kinetic theory. For questions pertaining to rates of reactions, please use the kinetics tag instead.

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11
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2answers
1k views

Why does gas particle velocity affect rate of effusion?

I understand why smaller particles have more velocity, but I don't understand what velocity has to do with the rate of effusion: My reasoning is thus: Pressure is the number of impacts of particles ...
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1answer
152 views

Change in pressure?

Consider a sample of gas in a fixed volume container . From the arguments of Kinetic Theory of Gases on quadrupling the temperature what will be the effect on pressure . Basically I thought that the ...
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1answer
571 views

Does lowering temperature of a gas make it easier to compress?

My teacher said that for ideal gases, the lower the temperature, the lower the kinetic energy of a gas will be, and it will be easier to compress the gas. Using the ideal gas equation $PV=nRT$, if ...
9
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3answers
123 views

Comparing van der Waals constant for gases

How can I compare the van der Waals constant $a$ (the liquefication constant) for different compounds based on my knowledge of bonding in the compound? Let's pick the following sample set: $$ \...
8
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1answer
27k views

Derivation of mean speed from Maxwell–Boltzmann distribution

I found that if a velocity of a gas follows the Maxwell–Boltzmann distribution, the mean velocity is given by $$\langle v \rangle = \sqrt{\frac{8RT}{\pi M}}$$ where $R$ is the gas constant, $T$ is ...
11
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3answers
21k views

Reason for negative Joule Thomson coefficient of Helium and Hydrogen at NTP conditions

Recently, while reading my textbook I came to know that Helium, Hydrogen and Neon are the only gases which have negative Joule Thomson coefficient at NTP conditions, i.e heating effect is observed ...
-2
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1answer
1k views

Maximum in Maxwell–Boltzmann distribution [closed]

I need to find the velocity at which the fraction is maximum in Maxwell–Boltzmann distribution $$P(v) = \left(\frac{m}{2\pi kT}\right)^{\frac{3}{2}}4\pi v^2 \exp{\left(-\frac{mv^2}{2kT}\right)}$$ I ...
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0answers
49 views

Which formula for kinetic energy of 1 mol of a gas is universally applicable? [duplicate]

I have read 2 formulas for kinetic energy of 1 mol of gas - 3/2 RT and 1/2fRT . But if I equate them then f comes out to be 3 . But f is different of mono, di, polyatomic gases . Where am I wrong in ...
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1answer
27 views

Graham's Law of Effusion when Looking at Samples with Equal Mass?

So, I had a question on a chemistry test about two gas samples, one of O2 and one of N2, that had equal masses. We were given the time of effusion for the sample of N2 and then asked to calculate the ...
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2answers
92 views

Change in Enthalpy in Free Expansion of Ideal and Real gas against Vacuum

By free expansion, I am referring to gas allowed to expand freely against vacuum in a Joule Expansion. If gas is ideal then change in Internal Energy '∆U' and change in Enthalpy '∆H' is zero. (By ∆H = ...
6
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5answers
545 views

Is the average kinetic energy of evaporating water molecules (at room temperature) equivalent to the average kinetic energy of boiling water?

Purpose: On new year's eve, after a splendid red and an assortment of sumptuous repasts, I made a bold remark which, on further consideration, may turn out to be incorrect. Unless! Unless I can ...
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3answers
343 views

Why is the speed of ideal gases mass dependent while the kinetic energy is not?

The rms speed of an ideal gas is $v_{\text{rms}}$ = $\sqrt{\frac{3RT}{M} }$ and the kinetic energy is $E_\text{k} = \frac32RT$. From this, it is concluded that the speed is mass dependent, while the ...
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1answer
60 views

Question regarding $Z$ (Compressibility factor)

Oh! This problem has been bugging me for a long time. According to Wikipedia, the Compressibility factor $Z$ is defined as the ratio of the volume occupied by a real gas to the volume occupied by an ...
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0answers
17 views

Why is pressure correction in Van der Waals equation positive [duplicate]

In real gas, there exist some attraction forces as opposed to what the Kinetic Theory of gases had proposed. Due to attraction, shouldn't the gas molecules strike the walls of container at a lower ...
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2answers
97 views

Why are some liquids hotter than room temperature gases if liquid and solid molecules move more slowly than gases? [closed]

We learned in school that state change is a matter of molecules moving faster and faster. And we learned "heat em up, speed em up, spread em out". Why then can some liquids have higher ...
-1
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2answers
732 views

Under what conditions does Real Gases show Ideal Behaviour? [closed]

MY textbook says : Real gases show Ideal Behavior under low pressure ,high temperature. So I wanted to know what happens to real gases at high pressure ,low pressure Do they also show ideal behavior ...
6
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1answer
31k views

Calculating Compressibility factor from the Van der Waals' Gas equation

So this problem has been bugging me for a long time. According to Wikipedia the compressibility factor $Z$ is defined as the ratio of the volume occupied by a real gas divided by the volume occupied ...
6
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2answers
626 views

According to KMT, is the velocity of an ideal gas always sqrt(3RT/M)?

It is a common textbook question to treat the root mean square velocities of an ideal gas as given by the following equation: $$v_\text{rms}=\sqrt{\frac{3RT}{M}}$$ I was wondering about the validity ...
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2answers
2k views

Why 1 mole of H2 occupied the same volume occupied by 1 mole of O2?

I'm asking a question about the volume occupied by gasses in standard temperature and pressure. My textbook said that a mole of any gas occupies $\pu{22.4 L}$ at standard temperature and pressure. But ...
0
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1answer
92 views

Ideal gas equation derivation proportionality [duplicate]

While deriving the Ideal gas Equation using Boyle's, Charles', and Avogadro Laws, how are each of the laws, which have different proportionality constants and different quantities as constant combined?...
1
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1answer
618 views

What gas law is involved when your ears “pop” when you are on a plane high in the air? [closed]

When you are up in the air, the air pressure decreases and the altitude increases. What gas law is involved in the situation wherein your ears "pop" because of the difference in pressure.
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1answer
481 views

Adiabatic expansion of gas

If a real gas is adiabatically expanded against constant pressure, then which of the following will definitely increase? Compressibility factor (Z) or Entropy (S) Correct answer: Entropy My answer: ...
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0answers
41 views

Estimating amount of Hydrogen Sulfide released into the air? and how fast does gas expand when it is produced?

I unknowingly exposed myself to hydrogen sulfide gas and am trying to figure out how much Hydrogen Sulfide gas i may have been exposed to. I mixed .5 grams of Sodium Sulfide Nonahydrate into a ...
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1answer
62 views

Maxwell's distribution function for mixture of ideal gases

I came across a question demanding relations between the individual distribution functions $f_n$ for the $n$th gas, and the overall $f$ for the entire mixture. I believe there is no simple way to ...
2
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1answer
61 views

Rigorous reason behind internal energy change being zero while mixing

A container is divided in two parts: one part contains oxygen gas $(n_1$ moles, at temperature $T_1)$ and the other part contains helium gas $(n_2$ moles, at temperature $T_2).$ The partition ...
2
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1answer
2k views

Finding root-mean-square speed of neon using kinetic energy

Find the root-mean-square speed of $\ce{Ne}$ atoms at the temperature at which their kinetic energy is $\pu{6.24 kJ mol-1}.$ I tried using the kinetic energy formula $$\mathrm{KE} = \frac{mv^2}{2},$$ ...
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2answers
38 views

Crossing at critical temperature of a gas

This is written in the book 'Treatise on Thermodynamics' by Max Plank- the crossing of the critical temperature at any pressure other than the critical pressure differs in no way from the crossing of ...
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0answers
16 views

The interactions of the high energy gas particles

When we are talking about the idealization of the gas, why for high temperatures its particles interact less? I would say you have a bigger probability of the collisions among particles. Quantum ...
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0answers
68 views

Calculating force and pressure of an ideal gas on a wall [duplicate]

The text below is from a discussion on ideal gases and the kinetic theory of gases: After the collision the molecule must travel a distance $l$ to the opposite wall, and then back across this same ...
0
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1answer
44 views

Relative humidity at constant temperatures [closed]

It’s known that Relative humidity = (water pressure in a certain volume/ saturated water pressure in the same volume)* 100% “at the same temperature” So my question is why does the amount of water ...
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0answers
20 views

Energy and impurities balance for adsorption with a fixed bed (with description)?

Do you have any suggestion where to look for a source of information about energy and impurities (component) balance for adsorption of mixture CO2/H2O in fixed bed? I have looked into many articles /...
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1answer
404 views

Vapor Pressure and Boiling Point [duplicate]

I heard that the boiling point of a solution is the temperature where its vapor pressure at that temperature equals the atmospheric pressure at that temperature. Thus at higher altitudes, as the ...
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2answers
2k views

The respective speed of five molecules are 2, 1.5, 1.6, 1.6 and 1.2 km/s. The most probable speed in km/s will be?

The respective speed of five molecules are 2, 1.5, 1.6, 1.6 and 1.2 km/s. The most probable speed in km/s will be? 1. 2 2. 1.58 3. 1.6 4. 1.31 I think the answer should be 1.6 km/h but the ...
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2answers
255 views

The amount of heat energy required to raise the temperature of 1g of helium at NTP from T1 K to T2 K is?

The amount of heat energy required to raise the temperature of 1g of helium at NTP from $T_1 \pu{K}$ to $T_2 \pu{K}$ is? My confusion is, that as the gas is at NTP, therefore, it is an isochoric ...
3
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2answers
564 views

Compressibility factor (Z) of a real gas [closed]

I was wondering whether the compressibility factor of a real gas (given by $Z = V_{\mathrm{real}}/V_{\mathrm{ideal}}$) is supposed to be measured while keeping pressure constant? I was attempting to ...
0
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1answer
33 views

If the gaseous molecules didn't have any kinetic energy would the surface of a filled balloon still be firm? [closed]

The most of the ideal gas law equation is based on the fact that the gaseous molecules are moving around and cause collisions and thus have some pressure. If these molecules were to not have any ...
0
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1answer
154 views

What is the relative rate of diffusion of ammonia to hydrogen chloride, both in gaseous states? [closed]

I encountered this problem during an assignment: I answered it as C, but the assignment grader marked it as wrong and indicated that A is correct. I asked another instructor about it and gave me a ...
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2answers
3k views

Does gravity affect the trajectory of gas particles?

We're studying the kinetic theory of gases in school, and one of the points that was brought up was that: "Gases consist of particles in constant, random motion." How is it possible for gas particles ...
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2answers
47 views

Will NH3 gas decompose into N2 and H2 at 250 degrees celcius? [duplicate]

If I heat ammonia gas to 250 degrees celsius, will it decompose into its basic components - N2 and H2? What temperature is required for the reaction to occur?
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1answer
71 views

Is it possible to determine the composition of a gas mixture from the effusion of a gas through a pinhole?

Typically all the problems which I've seen regarding rate of diffusion involve relating the rate of one gas to the other and from there finding either speed of effusion or diffusion or getting the ...
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1answer
764 views

Effect of pressure on viscosity of liquids and gases [closed]

My textbook says the following on viscosity and pressure: increase in pressure decreases the viscosity of water but for other liquids it increases. Viscosity of gases does not change much No ...
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2answers
18k views

Is Internal Energy = (3/2)nRT for a ideal monoatomic gas?

Internal Energy is a state variable and its value at a particular state cannot be measured; only the change in internal energy can be measured. So how come we write that $$U=\frac32nRT$$ where $U$ = ...
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2answers
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Why does water vapour deviate much more from ideal gas behaviour as it is cooled compared to nitrogen gas?

My guess is that it is something to do with the difference in boiling point between the two aforementioned molecules. But I can seem to come up with a logical explanation to why this is the case.
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Is kinetic energy proportional to temperature for non-gases?

If the molecules in a sample of ice at $\pu{-15 °C}$ and $\pu{1 bar}$ all have their kinetic energy doubled, then what is the final phase? The answer is gas, but I am not sure how to get this answer. ...
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0answers
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Determining heat capacity of gasses

I need a little help on answering a question which popped into my head while I was reading about gas laws: Suppose that I have three canisters, each holding a different gas of unknown identity [...
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0answers
46 views

Validity of Maxwell-Boltzmann distribution for solids [duplicate]

Suppose there is a solid made of avogadro number of, say, aluminium atoms. This solid is kept at 273 K. According to Maxwell-Boltzmann distribution, all the particles or atoms will not have the same ...
18
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6answers
5k views

Does the Maxwell-Boltzmann distribution apply to gases only?

The Maxwell-Boltzmann distribution can be used to determine the fraction of particles with sufficient energy to react. I know that the curve applies to gaseous reactants and would like to know whether ...
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0answers
55 views

Is it possible to use the laws of termodynamics for non-ideal systems?

For the reaction $$\ce{2CO(g) + O2(g) -> 2CO2(g)}\quad\Delta H = \pu{−560 kJ}$$ it is given that the reaction occurs at constant volume of $\pu{1L}$ and the initial and final pressures are $\pu{...
2
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0answers
893 views

Kinetic Diameter: How to calculate it? Pressure influence?

Wikipedia states: Kinetic diameter is a measure applied to atoms and molecules that expresses the likelihood that a molecule in a gas will collide with another molecule. It is an indication of the ...
3
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0answers
44 views

What gas would be suited best to form a density gradient in a long tube? [closed]

I want to set up an aero-optics experiment using a sealed ~5 m length of pipe with a gas inside. The gas must form a density gradient, and must be transparent enough to view a target at the other end ...