So, I've been studying some aerodynamics. And I came across the ideal gas equation:

pV = nRT

which is not hard to remember. What confused me was the word document has multiple versions of this equation that I have never seen online before, only in the document. I have friends who went to engineering college and they also never heard of those versions. They go like this:

"pV = nRT, since V = 1/ γ , the equation can be written as p/ γ = nRT γ = δ g -> p/ δ *g = nRT, so the equation is also p/ δ =ngRT."

And I input words here because there is no explanation whatsoever. In the real doc, it's just equations and that's it. I have no idea what the gamma symbol is, I have no clue what delta is but my professor referred to it as the greek symbol "Ro" so I guess he doesn't know what Ro looks like. And also I do not know why "g" becomes a thing in the equation. It's the acceleration from gravity, but I have no clue why it suddenly becomes a thing. And the "p/ γ = nRT γ = δ g -> p/ δ *g = nRT" part is written like that in the document, without any explanation whatsoever.

Hello, I'm trying to figure out if some data collected in our lab is of good quality. While I'm searching for data in literature, I wanted to figure out if the measured pressure is ok relative to an ideal gas.

My test is run in a 100cc cell. I have 25ml of water in the cell at 45C (vapor pressure of H2O at that temperature is 1.5psia).

I inject a known amount of CO2 into the cell (let's say 2g). The pressure of the cell is then measured after equilibrium is reached. The intention of this experiment is to progressively increase CO2 to estimate solubility (and Henry's coefficient of the mixture).

To calculate the ideal gas pressure, I did the following:

Available volume for gas: 100 - 25 = 75cc.

Assuming gas phase is mostly comprised of CO2 since the temperature is above the critical temperature of CO2:

P = (2/44.01) x 8.314 x 318.5/(75*1e-6)

The result is 232psia. Since CO2 dissolves in water, the actual vapor should contain less than 2g CO2 and should always have lower pressure than what I calculate.

Is this calculation appropriate for this situation?

I was reviewing my AAMC FL today, and came across this line in the solution to a question "The molar volume of an ideal gas at 25°C is 24.4 L, not 22.4 L."

However, in both UKnowWho and BP full lengths I had problems that involved calculating things with the assumption that one mole of a gas occupied 22.4 L of space, and a MileDown card saying the same. Is there something I'm missing here? is the 22.4 a different situation from 24.4? Are all of the other resources wrong?

Thank you for your help!

I am currently seeing an issue between the physically measured weight of compressed gas cylinders and ideal gas law suggested gas weight.

Assuming a 550ci cylinder filled with pure helium at 72 degrees F at sea level. Allowed to rest to stabilize the temperature and topping off to 6000 psi I am coming out 15% lighter in gas weight as compared to ideal gas law calculations. The pressure is being checked with calibrated analog and digital pressure transducers.

I am physically measuring 1.17lbs of gas and ideal gas law says I should be at 1.33lbs.

Is there something I am doing wrong here?

Factors I am considering:

Water volume of cylinder = verified

gas temp = allowed to rest at 72F to verify

Purity of helium = ? assuming there could be some mix of nitrogen or other gases in our helium the physical weight would only get heavier

I expect some deviation here but 12-15% seems like a lot

So I’m a physicist but I’m taking thermodynamics this semester, and we’re going over the ideal gas law PV=nRT. One thing that I know particle physicists do from time to time is define their units so that c (the speed of light) =1, because c shows up so many times in relativistic equations that this greatly simplifies the calculations. Then they just go back and add c where it should be to make sure their units work if they have to. I’m just wondering if there’s any field in chemistry where they do this too, like maybe if someone did nothing but work with gases in a lab setting or something? Is it ever really practical/does anyone ever really do it? How about in other places in chemistry?

Alternatives:

a) Because, to reduce the volume, it is necessary to carry out work on the gas.

b) Because the pressure must increase to compensate for the volume reduction.

c) Because the transformation is not adiabatic.

d) Because, to reduce the volume, it is necessary to transfer heat to the gas.

e) None of these alternatives is correct.

My answer:

E).

Because since the number of moles in the system is constant, there will be a greater number of collisions with the walls of the container.

Formula: Ca + 2 HF -->CaF2 + H2

18mL of HF of 6M . Find theoretical yield of hydrogen.

-Using dimensional analysis: I converted mL to liters. multiplied by 6 molarity and then divided it by moles of hydrogen then multiply by atomic weight of H2.

I am thinking we have to use density in order to find grams of HF but I am stuck at how to proceed with 6 Molarity in relation to moles HF and H2.

YouTube philosphers and the ideal gas law...

(Disclaimer: I am a doctoral candidate of 4 years in numerical astrophysics, and since January I am working as the sys admin of that institute, because I don't have much work left for my thesis and I want to transition out of academia when I'm done anyways... also, my contract would have run out at the end of february)

I've had it with YouTube philosophers.

First, there was Perspective Philosophy, who, in his "[reaction] to destiny's moral breakdown" ( YouTube Link ), wanted to tell us that all the ideal gas law has exceptions and thus even the natural laws have exceptions ( time stamp in the video ). That is incredibly wrong, I don't even know where to start (but I will in a minute).

Now, there is this Brenton Lengel guy who tries to tell us that the ideal gas law is inconsistent, thus even the natural sciences are inconsistent, blablabla. And don't get me started with this his takes on Goedel's incompleteness theorem and set theory (literally don't. I'm not a mathematician. I think I actually understand these things, but I'm not gonna test that against random redditers, because chances are that I don't actually understand them well enough... Unlike a certain Brenton Lengel I am very aware of where my self-perceived capabilities end.)

This might come as a shock to most people, apparently, but: The ideal gas law is an EXACT rule (yes, despite the "it doesn't work for certain gases under certain conditions", hear me out). The ideal gas law describes a NON-REAL gas with very specific featues, but for that gas it is exact; it has no "exceptions", because it is not a real gas, it does not really exist. To quote Wikipedia, which actually captures this pretty well:

"The ideal gas law, also called the general gas equation, is the equation of state of a hypothetical ideal gas."

Or in other words, it IS the equation of state of the HYPOTHETICAL ideal gas. Furthermore:

"It is a good approximation of the behavior of many gases under many conditions, although it has several limitations."

We use the ideal gas law to approximate other gases. This approximation, like all approximations, can be pretty good (like for atomic hydrogen gas at at least moderately high temperatures and low pressures (otherwise you w

Hi guys! Could you please help me understand how the Ideal Gas Law and the air conditioner mechanism are related?

I've been studying ideal gases and thermal machines, but I didn't really understand how the Ideal Gas Law and thermal machines are related in a practical example. The air conditioner seemed like a nice and different example (since I only see questions about fridges) that's why I brought this question.

My difficulties are around the "pV =nRT" equation and it's applicability and effects on a practical example, such as an air conditioner.

Anyone has the derivation of the equation in the title? I tried to find everywhere this but I only get the derivation for Van der Waals equation of state, thank you!

Or is the ideal gas law more of a "spherical cow" thing, hence the name "ideal?" I was trying to think of a possible example where n vs mass would make a big difference and diesel and otto cycle engines came to mind as one possibility. In a diesel engine, only air is (or, should be) in the cylinder during the intake and compression strokes (and it doesn't get hot enough to fuse atoms), so mass and n should be constant; in an otto cycle engine, gasoline is vaporized in the intake port and mixes with air throughout the intake and compression strokes, and perhaps the number of molecules matters?

Thanks!

The question is as follows:

"A 150dm3 cylinder is filled with oxygen gas at a pressure of 270 kPa and a temperature of 25C. If the lid of the container is opened to the atmosphere at sea level, what volume of gas will escape from the cylinder if the temperature remains constant."

I think I could probably solve it using Boyle's law to get the second volume (and that's what the solution provided did), but I'm kinda confused about why it works. Shouldn't the volume of the gas become infinite when it is opened to the atmosphere?