Questions tagged [gas-laws]

Physical and chemical laws describing the properties and behavior of gases. This tag currently applies to properties and laws concerning both ideal and real gases.

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Can a vacuum on a closed system really “pull” things out of it?

So I’m learning gas discharge tube making (neon) and there’s a step where you cork one end of the tube and pull a vacuum on the other end to suck out all the impurities. The same thing was done when I ...
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Formula for collision frequency and mean free path

We were studying collision frequency and mean free path today, and in it, we got the equations of collision frequency as: $$Z=\sqrt 2 \pi \sigma^2v_{rms}N$$ where $N$ is the number density, equal to $...
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Is it appropriate to say "solid-in-gas solution" and "liquid-in-gas solution"?

A number of books mention "solid-in-gas" and "liquid-in-gas" types of gaseous solutions. However, for something to dissolve in a gas, it must be in its vapour phase. So, for ...
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Why is my P-T gradient decreasing for increasing radius of spheres when it should be increasing? [closed]

Why is my P-T gradient decreasing for increasing radius of spheres when it should be increasing? I'm simulating some hard sphere collisions with $Radius_{container}=10,$ and varying pressure and ...
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63 views

Is the value for the Boltzmann Constant different in 2D?

So I'm simulating some hard sphere collisions and want to determine the Boltzmann constant in two dimension, using the equation $$PA=Nk_BT$$ where $A=\pi R^2_{container}$, $P=(averageImpulse/time)/(2\...
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28 views

what is reversible change for an ideal gas?

Sorry for my unclear question... I am struggling with understanding what reversible/irreversible changes are for an ideal gas. Is it the change that keeps the ideal gas law during the change? Is any ...
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1answer
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why can water heated to a certain temperature in microwave explode when removing cup , bowl etc to room temperature air? [closed]

Studied a lot about $\mathrm{pH}$ , molecule dipoles properties $\ce{H2O}$. never saw anything along lines of energy storage, except ice contains heat energy , ionization of water always happens. ...
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Relationship of oxygen dissolved in water with bubble time and temperature

I'm using the Winkler method to calculate oxygen dissolved in water. This is at the temperatures 20, 30, 40, and $\pu{50 ^\circ{}C}$ and I bubbled a controlled amount of oxygen in through the reaction ...
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1answer
64 views

Method of cooling a gas without liquid evaporation for Sci-fi novel

sorry for the amateur question here. I know little about science, but regardless am writing a fictional amateur novel that deals with a lot of chemistry stuff, especially gasses. My protagonist needs ...
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1answer
78 views

Dissociation of phosphorus pentachloride in gas syringe

Phosphorus pentachloride is introduced into an empty gas syringe which has a movable, tightly-f‌itting plunger. The gas is allowed to expand until equilibrium is reached at a temperature at which the ...
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1answer
89 views

Do benzene and hexane form an ideal solution?

My teacher said that benzene and hexane do not form an ideal solution (with reference to Raoult's law) but did not explain any reason for it. My approach: Cyclic hydrocarbons (benzene here) have ...
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1answer
55 views

Pressure increase in a chamber with 1 ml of water heated to 200 °C [closed]

For safety reasons I want to know how much pressure will be generated in a sealed chamber with $1~\mathrm{ml}$ of water, pure nitrogen at $1.3~\mathrm{bar}$ at $22~\mathrm{^\circ C}$. This chamber ...
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1answer
103 views

How can I calculate the density of a gas mixture using the ideal gas?

I am trying to calculate the density of the ideal gas mixture given the following data: The gases are helium and oxygen. There are $\pu{8 g}$ $\ce{He}$ and $\pu{16 g}$ $\ce{O2}$. The temperature is $\...
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2answers
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How does change in temperature affect experimental calculation of molar mass

This is coming from AP Chemistry 2009 q2 f. To sum it up, a student undercalculates the molar mass of a gas that is flushed into a sealed flask of dry air using DRT/P, and you have to justify if the ...
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1answer
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What gas particles are formed when diamond turns to gas?

If you heat up diamond away from oxygen (air completely) until the solid diamond is now gaseous, what are the gas particles made of? Just the element carbon without a charge?
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Reversible compression and proving relation with state function

I am currently working on a question I am having problems with. I tried to solve it, but to no avail; it states that this expression is always valid for any three-variable dependent function: It ...
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1answer
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Is there a way to put helium or any other gas into food?

Kinda like pop rocks puts bubbles of carbon dioxide gas into their candy to make it pop, If someone put bubbles of helium into some sort of food light enough then would it float? And how do they even ...
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1answer
367 views

An atom moving at its root-mean-square speed at 20 °C has a wavelength of 32.8 pm. Identify the atom

An atom moving at its root-mean-square speed at $\pu{20 °C}$ has a wavelength of $\pu{3.28E-11 m}$. Identify the atom. Here's what I did: $$u_\mathrm{rms} = \sqrt{\frac{3RT}{M}}$$ and $$ \lambda = \...
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1answer
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How do I find the volume of a gas when the pressure and temperature changes, given the original volume? [closed]

I am a sophomore in high school, just started honors chemistry this year, and I'm having trouble figuring out what formula to use for this question, and how exactly to do so: If a gas has an original ...
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3answers
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Does the amount of a gas increase with pressure? [closed]

The graph of $pV/(RT)$ shows that different gases deviate differently from ideal gas behaviour and that the value of $pV/(RT)$ changes as pressure increases. My question is, if $pV/(RT) = n$ or amount ...
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Is a/b > 1 mol/L for a and b in the van der Waals equation?

We know that the van der Waals equation for real gases is $$\left(p + \frac{an^2}{V^2}\right)(V-nb) = nRT.$$ Is $a > b$ always in this equation? In my textbook $a > b$ for gases like $\ce{He},$ $...
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1answer
69 views

PV=constant and V/T=constant then why PT is not constant? [closed]

We know that P1V1=P2V2 by Boyle's Law. Let's say this equation (i). And we know that V1/T1=V2/T2 by Charle's Law. Let this equation be (ii). Dividing (i)/(ii), we get P1T1=P2T2... But it's completely ...
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1answer
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Doubts regarding Mole concept and Avogadros number [closed]

So I am really confused about simple topics like mole and Avogadro Here is my oversimplified view So mass of 1 atom of elements in grams was not in whole numbers and it was difficult using em for ...
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About Real Gas and Ideal Gas - Select the correct statement(s):

Select the correct statement(s): At Boyle's temperature a real gas behaves like an ideal gas at low pressure. Above critical conditions, a real gas behaves like an ideal gas. At high pressure van der ...
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Can different components show different deviations from Raoult's law?

Introduction: Raoult's law is used to calculate the partial pressures of the vapour phases of volatile components of a solution Given that there are two components, A and B, in the liquid-liquid ...
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1answer
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If something is not hydrophilic, is it necessarily hydrophobic?

Is it possible to create hydrophobic water? Two species are phobic within some medium under some conditions when they don't here together (cohere if they're the same species; adhere otherwise). To be ...
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2answers
119 views

Why does van der Waals' equation of state give only one P, V pair for a particular temperature here?

I came across this question which I initially ignored believing that the data was insufficient: Calculate the pressure exerted by one mole of $\ce{CO2}$ gas at $\pu{273 K}$ if the van der Waals' ...
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1answer
29 views

Effect of inert gas blanket on oxygen solubilized in wine

If applied to a volume of wine, could a blanket of argon become dense enough to remove oxygen from the wine? This is not a question of sparging the wine. Rather, could a blanket of argon over the top ...
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What unit and dimension for membrane permeability / permeation expression?

Context When studying the diffusion of gases through thin membrane, one may use the diffusion coefficient $D$ used in Fick's laws as (one dimension form): \begin{equation} J = - D \cdot\frac{d\varphi}{...
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1answer
196 views

How to calculate Kp without knowing the volume? [closed]

I have the following chemical equation: $$\ce{Sb2S3 + 3H2 <=> 2 Sb + 3H2S}$$ I have $\pu{1000 grams}$ of $\ce{Sb2S3}$ that reacts with $\pu{10 grams}$ of $\ce{H2}$ in a reactor at $\pu{713 K}$. ...
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1answer
65 views

What are chemicals that will create a similar reaction to baking soda and vinegar for my book?

I'm writing a book based on a dream I had, but after some research I can't find too much on a specific reaction I want. The main character mixes a clear liquid and yellow powder which hisses and ...
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When do repulsive forces in a gas actually become dominant?

We say that repulsive forces become dominant when Z>1 (i.e. Vobserved > Vtheoretical). But when the difference between Vobserved and Vtheoretical is less than b, shouldn't attractive forces ...
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1answer
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Does the critical temperature of a gas depend on the amount of the gas taken?

Does the critical temperature of a gas depend on the amount of the gas taken? Or is it independent of it? My book does not specify this point. I think according to the gas laws, the critical ...
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1answer
110 views

Pressure of two flasks connected to each other at different temperatures [closed]

Two flasks of equal volume connected by a narrow tube (of negligible volume) are at $\pu{27 °C}$ and contain $\pu{0.7 mol}$ of $\ce{H2}$ at $\pu{0.5 atm}$. If one of the flasks is then immersed into a ...
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3answers
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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: $$ \...
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0answers
65 views

Complex formation in water and Henry's law

I've been trying to solve the following problem for a while now. Consider a mixture of two different gases ($A$ and $B$) for which Henry's law holds. When gas molecules $A$ and $B$ do not interact ...
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1answer
100 views

Dissolution of CO2 in water

The following question has troubled me for a while. For gases that are slightly soluble in water, there is a proportional relationship between the partial pressure, $P$, and the mole fraction, $x$, ...
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1answer
67 views

Partial pressure of gases in a container with a piston

I've been having problems with the following problem. Figure 1. A container with a piston like that shown in Figure 1 is filled with $0.10$ $mol$ of Ar and $1.00$ $mol$ of water (liquid and vapor). ...
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1answer
104 views

Finding the mole fraction of nitrogen in a mixture of nitrogen and oxygen

Question The density of a mixture of Nitrogen and Oxygen is $\pu{4.7 g L-1}$. Its given that $P = \pu{4 atm}$, and that $T = \pu{298 K}$. Assuming both gasses are ideal gasses, what is the molar ...
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1answer
103 views

Equilibrium composition of methane–water system under given conditions

Calculate the equilibrium composition of a reactive system consisting of an equimolecular mixture of $\ce{CH4}$ and $\ce{H2O}$ at $\pu{900 K}$ and $\pu{1 atm},$ considered to be an ideal mixture of ...
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1answer
54 views

Finding half-life of a nuclide based on gas release

Full Question: The hydride of an unstable nuclide of a Group IIA metal, $\ce{MH2 (s)}$, decays by alpha emission. A $\pu{0.025 mol}$ sample of the hydride is placed in an evacuated $\pu{2.0 L}$ ...
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0answers
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How to determine the concentration of oxygen in a nitrogen/oxygen mixture?

I need to prepare a 10% oxygen in nitrogen mixture for an aerobic reaction I'm developing in lab and I found an old instrument in someone else's lab that controls the flow of two gases. So I am able ...
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4answers
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Why does gas not liquify at a temperature above the critical temperature no matter how much pressure is applied on it? Why? [duplicate]

My textbook says that critical temperature is the temperature above which a gas cannot be liquified no matter how much pressure we apply on it. But why? What is so special about this 'critical ...
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1answer
122 views

Finding molar mass of uranium fluoride using Graham’s law of diffusion

Problem A sample of uranium fluoride is found to effuses at the rate of $\pu{17.7 mg/h}.$ Under comparable conditions, gaseous iodine effuses at the rate of $\pu{15.0 mg/h}.$ What is the molar mass ...
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1answer
111 views

What is inside nanobubbles?

A recent article (ACS Omega 2021, 6, 8021−8027) confirms the stability of nanobubbles with theoretical principles. Nanobubbles, having a size in the range of 50-500 nm, are reported to be metastable, ...
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1answer
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Understanding Joule-Thomson expansion apparatus

I am reading the Joule-Thomson experiment and although I can follow the mathematics I can't understand what is going on. Here is the apparatus                                                     taken ...
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1answer
162 views

Calculating atomic mass of unknown element in given compound (gas) at STP

A gas $\ce{X2O5}$ has the density of $\pu{5 g L-1}$ at STP. What is the atomic mass of $\ce{X}$ given $A_\mathrm{r}(\ce{O}) = 16?$ Note: The problem is my homework for school and has been translated ...
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1answer
90 views

Can potassium carbonate be used to calibrate hygrometers?

Context: In the process of trying to calibrate a number of hygrometers, with Sensirion MEMS electronic sensors, I came across the method of using wet salt: an airtight container will stabilize at a ...
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2answers
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What would be the physical interpretation of the equation dG = Vdp − SdT?

I was trying to understand the derivation of the formula $G=G^\circ+RT\ln (p/p^\circ)$ starting with the following relationships: $$ \begin{align} \mathrm dU&=T\,\mathrm dS-p\,\mathrm dV\tag{1}\\ \...
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1answer
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Find gas pressures of injection knowing mixture pressure without knowing volume

Let's say we have a gas 1 moving inside a pipe (we don't know the geometry) at mass flow rate $Q_1$ and temperature $T_1.$ We inject a gas 2 at some point inside the pipe with gas 1 at mass flow rate $...

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