Physical and chemical laws describing the properties and behavior of gases.

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What allows all 3 states of H₂O to be present at the same time?

How is it possible for there to be a glacier floating on water but under clouds? Depending on the temperature, shouldn't there only be one state of water?
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1answer
21 views

Permanent Balloon?

Is it possible to create a container for helium that it can't permeate through, like a permanent balloon? Or, if not, what kind of material would have the lowest permeability for that application? I ...
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1answer
13 views

Producing low Density Gas in Room Temp

Does anybody know two liquids or a solid and a liquid that can react to produce a gas less dense than air ( or similar ) in room temperature . This question is intended to make a chemical induced ...
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1answer
342 views

Are there any magnetic particles that are safe to inhale?

In medicine, there is an (old?) experiment where a subject is asked to inhale radioactive Xenon gas, and radiation counters are placed at different positions near the lungs. Using this experiment, it ...
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1answer
34 views

What is the density of compressed natural gas used for natural gas vehicles

I would like to know the density of the compressed natural gas used for natural gas vehicles in order to complete the formula in the following StackExchange post: ...
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1answer
35 views

Helium gas expand isobaric isothermal

If 4 mol helium gas expand against constant pressure in isothermal process. How can calculate w? Is it w=-nrtLn(v2:v1) as define by isothermal or is it w=-p(v2-v1)as define from isobaric? Also, is ...
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1answer
34 views

Why does a container in which a match burning cause suction?

As you see in picture a burning match in a container causes suction and this is a Traditional Therapeutic method to relive bone pain. What is the reason? I think it should be related to gas ...
2
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1answer
29 views

What determines humidity limit / dew point of the air? - Why can air only hold a certain amount of water?

From Wikipedia: The dew point is the temperature at which the water vapor in a sample of air at constant barometric pressure condenses into liquid water at the same rate at which it evaporates. At ...
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1answer
34 views

Collection of gas over water

When you collect a gas over water, you have to account for the mixed in water vapor by subtracting the room pressure from water vapor pressure. However, why do you not do something similar for volume, ...
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1answer
69 views

Prepare 1 liter of 28% NH3(aq) solution from 1 gal of %10 NH3(aq)

I have one gallon of commercial, surfactant free, ammonium hydroxide solution that I would like to use to prepare a concentrated solution. I have two options as I see it, and I am still getting into ...
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3answers
90 views

In order to be a gas does the pressure exerted by the gas has to be more than the atmospheric pressure?

In order to be a gas does the pressure exerted by the gas has to be more than the atmospheric pressure? Really simple, I think yes to this question but teacher says no. So what is your view into this? ...
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1answer
18 views

Is there any graph that depicts the deviation of real gases from Charle's law?

I am looking for a graph that shows the basic deviation of a gas from the Charle's law. The graph should be for different values of constant pressures.This would help me evaluate how gases follow ...
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0answers
29 views

Reducing NOx with Ammonia. Practical in a gasifier?

Sorry if this is an outright stupid question. I am no chemist... For Nitric Oxide: $2{NH_{3}} + 2 NO => 2 {N_{2}} + {H_{2}} + 2{H_{2}O}$ For Nitrogen Dioxide: $2{NH_{3}} + 2{NO_{2}} => ...
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2answers
39 views

Why two ( or more) gases have proportional volumes at constant pressure and temp.? (Avogadro's Law)

I am in real confusion over Avogadro's Law.. In some of the problems I did on gas laws, there are the number of moles of the gas, the temperature. and the pressure. And it expects me to find the ...
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1answer
41 views

Is this the correct equation for the mean free path?

$\lambda=\frac{KT}{\sigma p}$ is the equation given in my textbook but everywhere else I look it is different. Is it wrong? The derivation is as follows: $$\lambda = \frac{v_{rel}}{z}$$ where ...
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1answer
41 views

How do derive the equation for relative velocity of gas molecules

The relative velocity is $$v_{rel}=\sqrt2v_{mean}$$ where $v_{mean}=(\frac{8KT}{\pi m})^{\frac12}$$$v_{rel}=(\frac{16KT}{\pi \frac m2})^{\frac12}$$ because the reduced mass of two of the same ...
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2answers
71 views

How to get the first step of the derivation of the Maxwell-Boltzmann distribution

To derive the Maxwell-Boltzmann distribution the first step requires the knowledge that the equation will take the form $$f(v)=Ke^{-\epsilon/ kT}$$ where $\epsilon$ is the sum of the kinetic energies ...
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1answer
47 views

Calculate the root-mean-squared speed of free electrons in the Sun's corona given pressure, temperature and mass of an electron

$m_e=9.1×^{-31}kg$, $T=2×10^{6}K$ and $p=0.030Pa$ the solution is given as: $5.4×10^6 ms^{-1}$ but I got $9.5×10^6 ms^{-1}$ using the following method (which does not use the value given for pressure. ...
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1answer
79 views

Calculate the frequency so that the wavelength of sound in air would be equal to the mean free path in oxygen at 1.0 atm and 0ºC

Take the diameter of the oxygen molecule to be $3.0×10^{-10}$ m. Here's what I did: $$\lambda_{mfp}=\frac {K_BT}{\sigma p}$$ $p$ is pressure. Mfp stands for mean free path. ...
2
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1answer
77 views

Why can a gas only transmit sound waves whose wavelength is long compared with the mean free path?

Also when can this fact be useful? I don't really understand at all why this might be the case so any help would be appreciated.
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1answer
93 views

Percent composition, maybe?

I've attempted to solve this problem with percent composition, but it says the answer is wrong. Is it a PV=nRT problem, and if so, can I use the units as they are given? A 0.02867 g sample of gas ...
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1answer
23 views

A 4.00 L sample of gas is cooled from 67 °C to a temperature at which its volume is 2.60 L [closed]

A $4~\mathrm{L}$ sample of gas is cooled from $67~\mathrm{°C}$ to a temperature at which its volume is $2.6~\mathrm{L}$. What is this new temperature? Assume no change in pressure of the gas.
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1answer
11 views

Quick Stoich & Gasses

I have a quick question in Stoich and Gasses, I however could not get any far, any answer will be appreciated. Thank You. A sample of $\ce{Pb(NO3)2}$ is heated, yielding $\ce{O2, NO2\ gas,\ and\ ...
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1answer
60 views

Gas Stoichiometry & Ideal Gas Law

I need a little help with one of the problems below. Any help on the problem below will be appreciated. I don't want to sound like an idiot, I will also provide my work. Solid $\ce{NaHCO3}$ ...
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1answer
23 views

What will happen to the entropy and free energy of the gasses when the partition is removed?

Consider a container of volume $ 5.0$ L that is divided into two compartments of equal size. In the left compartment there is nitrogen at $1.0$ $atm$ and $25 °C$; in the right ...
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1answer
46 views

What conditions can cause a material to exist as a gas?

So my question is, how can something exist a gas. Is it when the pressure exerted by the gas is greater than the atmospheric pressure, then it is a gas? And also how do manometers work, how can you ...
3
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1answer
74 views

Where does this equation for the activity in the gas phase equilibrium between N₂, H₂ and NH₃ come from?

I have a question with Equilibrium Constant. I understand that for a reaction in equilibrium $aA +bB \rightleftharpoons cC +dD$ $$K_c= \frac{[C]^c[D]^d}{[A]^a[B]^b}$$ and $K_p$ is just using the ...
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1answer
94 views

Ideal gas law derivation from kinetic theory

Consider the derivation of the ideal gas law from kinetic theory presented here: http://en.wikipedia.org/wiki/Kinetic_theory I have some questions This derivation assumes the container is a cube, ...
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1answer
33 views

Proportion of gases in Ideal Gas Mixture?

Suppose methane ($CH_4$) and ethane ($C_2H_6$) in a container. The specific gravity is $r_g=0.6$. I think this means $0.6=\frac{\rho_{CH_4}}{\rho_{C_2H_6}}$. Now I am trying to understand the ...
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2answers
58 views

Compressible Factor

I 've a soft question on the terminology of compressibility factor. It is termed compressible factor because, its value determines how any reals gas is compressible with respect to an ideal gas ...
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3answers
48 views

Plotting p/T against T [on hold]

This is about the ideal gas equation $$pV=nRT$$ to plot ${p}\over{T}$ against $T$, where ${nR}\over{V}$ is constant. How would this graph look like?
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42 views

How to determine an unknown gas in a tube with a massless piston at equilibrium conditions?

There is a massless piston that can move freely in a horizontal tube that is closed at both ends. To the left, there is a sample of helium gas at $300~\mathrm{K}$ and $4~\mathrm{atm}$. To the ...
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0answers
55 views

How to find Gibbs energy for a real gas

I'm asked to find $\Delta G$ for the isothermal compression of $N_{2(g)}$ (real gas) at $0°C$ if the gas expands from $P=1\space atm$ to $P=1000 \space atm$. The fugacity coefficients are ...
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4answers
117 views

How to find the empirical formula for an nitrogen oxygen compound from the given mass of nitrogen and the product?

$5.00~\mathrm{g}$ of nitrogen is completely converted into an oxide of nitrogen. The mass of the oxide formed is $19.3~\mathrm{g}$. The empirical formula of the oxide would be? My working: ...
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1answer
85 views

Gas laws question, condensed partial pressure?

So I'm relatively new to gas laws as I just started learning it at school. I've been doing fine so far until I got stuck on this question, any ideas? A mixture of three gases N2, CO2 and O2 has a ...
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1answer
108 views

Volume of different gas in a container

I know that technically two or more gases in one container should have different volumes. But when you imagine the gas molecules being mixed together, it look sorta like the two gases have the exact ...
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1answer
1k views

Using combined gas law to calculate the volume of dry hydrogen gas

Pv/t = pv/t is the equation of combined gas law. Say if the volume of wet hydrogen gas is 40.48ml does this equation still work if part of that volume is water vapor. Or in another word, does the ...
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0answers
17 views

How to calculate the volume of dry hydrogen in magnesium/ HCl reaction [duplicate]

Sorry if this will sound trivial, I am not too sure if the moles of $H_2$ in the equation $Mg(s) + 2HCl(aq)\rightarrow MgCl_2(aq) + H_2$ is that of dry or wet hydrogen. If the $H_2$ refers to wet ...
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1answer
31 views

Stoichiometry of Gaseous Reactions

The Question: How many liters of $H_2S$ would be required to react with excess oxygen to produce $12.0$ $L$ of $SO_2$? The reaction yield is $88.5$%. Assume constant temperature and pressure ...
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1answer
71 views

How does pressure change reflects in this formula? [closed]

The pressure is missing or I guess is integrated in the adiabatic constant. But I don't know how to even derive the adiabatic constant for a certain gas.
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1answer
117 views

Finding Root-Mean-Square of Ne using kinetic energy?

I am not being able to solve the following question: -Find the root-mean-square speed of $\ce{Ne}$ atoms at the temperature at which their kinetic energy is $\mathrm{6.24\ kJ/mol}$. I tried ...
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1answer
61 views

Proof of kinetic energy equation

Is there a way to prove that $\frac{1}{2} mv^2 $$= \frac{3}{2}RT$ The first one is kinetic energy and the second is the average kinetic energy. Can this be proved by component of velocity.
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0answers
36 views

A way to rationalize avogadro's hypothesis

How can one rationalize avogadro's hypothesis using the equation of kinetic molecular theory. Did you see anything? I can't
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1answer
92 views

Will the propane liquefy?

Consider a 1:1 mix of propane and nitrogen at 60 °F and 75 psi. Will the propane liquefy if pressure is increased to 200 psi? This is a real world question. I am experimenting in the oilfield with a ...
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1answer
88 views

Undergrad Kinetic Molecular Theory

Gas A and B are placed together in a sealed container at room temperature and are pressurized to 2.5atm. After a period of time, there is a border between the two gases. Given A has a density ...
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1answer
60 views

Significance of Kinetic Velocities?

In the concept of Kinetic Molecular Theory we have rms(root mean square), avg(average) and mp(most probable) velocities. I understand the concept well. But my question is why do we have three ...
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1answer
74 views

Which gas is easier to compress, the ideal gas or a real gas?

Since the pressure of a real gas is less than that of the ideal gas and its volume is more than that of ideal gas, I am assuming that the real gas is difficult to compress in comparison to an ideal ...
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1answer
170 views

Calculating collision diameter with viscosity, but not having the mass given

I've got a homework question i'm stumped on. The viscosity of the ethylene gas was measured at $99.8*10^{-7} \textrm{ N s m}^{-2}$ at $288 \textrm {K}$. Calculate the collision diameter in ...
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1answer
46 views

The Van Der Waals Equation - High T and High $V_m$

This one is for my physical chemistry homework and I'm having trouble finding the answer. At high temperatures the Van Der Waals equation has the form $$P\approx\frac{RT}{V_M-b}$$ What would ...
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1answer
34 views

Addition of combined gas law constant

There are two containers connected to each other but separated by a cork. If container(1) has a gas $G_1$ at a volume $V_1$, pressure $P_1$ and temperature $T_1$ and similarly in container(2) there ...