#pv=nrt

[sohcah--toa]

Happy (belated) birthday to Osamu Dazai!! Side note, happy (also belated) birthday to Blaise Pascal~ I did a lot of binomial expansion to celebrate!! 🔺🎊

[bsideheart]

okay someone tell me to get off tumblr and lock in. i have chemistry to do

[sunalsolove]

Chapter 11

Chapter 11: Fitz

By @sunalsolove and @cherrylimeade

S4 AU. Fitz enters the Framework after killing Jemma's LMD. It's not what he was expecting, his team is missing, he's Jemma's ... bodyguard, and she's heading up ... Hydra? Jemma might not remember him, but he’s determined to save her- no matter what he has to do to wake her up.

Banner by @eclecticmuses

[florbo-0]

Just wait until they hear about the ideal gasfem law

massfem times accelerationfem

[saintkevorkian]

Consider the ideal gas law

𝑃𝑉=𝑛𝑅𝑇

where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is the temperature.

By rearranging the equation, it can be shown that pressure is inversely proportional to volume but directly proportional to moles and temperature.

𝑃= 𝑛𝑅𝑇 / 𝑉

Volume is inversely proportional to pressure but directly proportional to moles and temperature.

𝑉= 𝑛𝑅𝑇 / 𝑃

Temperature is directly proportional to the pressure and volume.

𝑇= 𝑃𝑉 / 𝑛𝑅

The number of moles present is directly proportional to the pressure and volume.

𝑛= 𝑃𝑉 / 𝑅𝑇

[beakers-and-telescopes]

OKAY THIS ARTICLE IS SO COOL

I'm going to try to explain this in a comprehensible way, because honestly it's wild to wrap your head around even for me, who has a degree in chemistry. But bear with me.

Okay, so. Solids, right? They are rigid enough to hold their shape, but aside from that they are quite variable. Some solids are hard, others are soft, some are brittle or rubbery or malleable. So what determines these qualities? And what creates the rigid structure that makes a solid a solid? Most people would tell you that it depends on the atoms that make up the solid, and the bonds between those atoms. Rubber is flexible because of the polymers it's made of, steel is strong because of the metallic bonds between its atoms. And this applies to all solids. Or so everybody thought.

A paper published in the journal Nature has discovered that biological materials such as wood, fungi, cotton, hair, and anything else that can respond to the humidity in the environment may be composed of a new class of matter dubbed "hydration solids". That's because the rigidity and solidness of the materials doesn't actually come from the atoms and bonds, but from the water molecules hanging out in between.

So basically, try to imagine a hydration solid as a bunch of balloons taped together to form a giant cube, with the actual balloon part representing the atoms and bonds of the material, and the air filling the balloons as the water in the pores of the solid. What makes this "solid" cube shaped? It's not because of the rubber at all, but the air inside. If you took out all the air from inside the balloons, the structure wouldn't be able to hold its shape.

Ozger Sahin, one of the paper's authors, said

"When we take a walk in the woods, we think of the trees and plants around us as typical solids. This research shows that we should really think of those trees and plants as towers of water holding sugars and proteins in place. It's really water's world."

And the great thing about this discovery (and one of the reasons to support its validity) is that thinking about hydration solids this way makes the math so so so much easier. Before this, if you wanted to calculate how water interacts with organic matter, you would need advanced computer simulations. Now, there are simple equations that you can do in your head. Being able to calculate a material's properties using basic physics principles is a really big deal, because so far we have only been able to do that with gasses (PV=nRT anyone?). Expanding that to a group that encompasses 50-90% of the biological world around us is huge.

[catboybiologist]

Hm who said not needing air cancels nitrogen toxicity, like. It doesn't come from lack of oxygen, it's a separate thing entirely

So only shalow freediving for you im afraid

Although

You know how weird mixtures people on deep dives do are mostly helium and or hydrogen

Those aren't overly expensive gasses, and you only need to breathe them on the surface for a bit to get all the nitrogen flushed away, then hold your breath

So yeah you can still dive deep, with this 1 cheap exploit

Not needing a tank of compressed air on your back would almost 100% fix any problems of oxygen and nitrogen toxicity you face, by definition. During record setting freedives, even to extreme depths of several hundred meters, gas toxicity is not a problem. Marine mammals do get DCI sometimes, but only because their lungs are proportionately so massive and have powerful diaphragms that they can function as a mildly compressed tank.

Decompression illness is from a buildup of breathing compressed nitrogen in air over time, causing compressed, low volumes of nitrogen to build up in your tissues. As you ascend at the end of a dive, these compressed nitrogen "bubbles" expand, creating a larger volume of nitrogen in your tissues than should be there, disrupting neuromuscular function. If you aren't breathing compressed air, this is by definition not a problem- the total "volume" that nitrogen could expand to within your tissues is theoretically bounded by the total "volume" it occupied at the surface, since you're not putting any additional air into your body.

Quotes around "bubbles" and "volume" bc this is using gas principles for explanation, but since nitrogen is actually dissolving and precipitating out of your tissues here, it's not always a gas in this example. But, thinking about the theoretical volume nitrogen could occupy if it were all a gas is a good way to conceptualize how much it will "force" it's way into your tissues.

If you need a mathy way to conceptualize this, try to think of it in terms of the ideal gas law. PV=nRT. In a normal scuba example, V remains constant as you descend, but since P is increasing, the equation balance by increasing n (the additional air from your tank). But, as you go up, P decreases, and V can't keep up, since nitrogen is not easily released from your tissues. In our example of not having to breath, V would not "replenish" itself, and would decrease at depth. n would not increase. V and P would simply proportionally adjust to each other, and crucially, this means that V can never go higher than it initially was as we ascend.

To summarize: DCI is caused by an additional input of air into your body at depth, not by the air you "take with you" from the surface. If you didn't need to breathe, you wouldn't need a tank, and there would be no nitrogen input.

Oxygen toxicity is more complicated but would work via a similar idea. Oxygen toxicity kicks in immediately, at depth, once oxygen is beyond a certain partial pressure. Again, however, we reach this same principle: that partial pressure is caused by an additional input of compressed oxygen being forced into your tissues by the water pressure. Without that additional input, the total number of oxygen molecules you have at depth is only what you being with you. PV=nRT, and you're not changing your n. As P goes up, V goes down in this example. Again, no additional n. This one also gets more complicated bc oxygen toxicity is balanced by the rate at which cellular respiration consumes this, but idk how that would work here when you magically don't have to breath.

Even if either one could theoretically cause problems for you, you can just purge your lungs before you dive.

So yeah. You don't need any other gases. The reason why other fancy gas mixes are used isnt to "purge" nitrogen, it's so that they take up more volume and more partial pressure than nitrogen or oxygen would in a standard gas mix.

This is a bad explanation, but the source on this is that I'm PADI nitrox certified lol

[oldinterneticons]

Don't be a PV=nRT!

[jpitha]

Under enough pressure, Ravioli behaves as a gas

This feels like something from @carionto’s universe:

> There was still one aspect of the whole concept of a ravioli-loaded > railgun type wepon which we, lolling about late on a weeknight, with > only a few neurons randomly firing, could not resolve.  Would a chunk > of metal (can of ravioli) impacting another, larger, rest mass > structure (star destroyer) produce an "explosion" effect, or simply > punch an appropriately shaped hole as it passed through?  Bill?

What am I, the neighborhood blast physicist???  Well, maybe... :-)

It all depends on speed of impact versus the speed of sound in the target (what is called the Mach number, where Mach 1 means the speed of sound, Mach 2 is twice the speed of sound, etc), and the speed of the ravioli versus the speed of light in the target (which I'll call the Cerenkov number, where Cerenkov 1 is the speed of light in anything; Cerenkov 1.3 is the speed of high-energy protons in a water-cooled reactor (that's why you get that nifty blue glow), and you can get up to Cerenkov 2.4 using diamonds and nuclear accellerators.  In the late 40's people used to talk about Cerenkov numbers, but they don't anymore.  Pity.).  Lastly, there's the ravioli velocity expressed as a fraction of the speed of light in a vacuum (that is, as a fraction of "c").  "C" velocities are always between 0 and 1.

At low speeds (REAL low) the ravioli will simply flow over the surface, yielding a space-cruiser with a distinctly Italian paint job.

Faster (still well below speed-of-sound in the target) the metal of the space-cruiser's skin will distort downward, making what we Boston drivers call a "small dent".

Faster still, you may have a "big dent" or maybe even a "big dent with a hole in the middle", caused by the ravioli having enough energy to push the dent through, stretching and thinning the hull metal till the metal finally tears in the middle of the dent.

Getting up past Mach 1 (say, 5000 feet/sec for steel), you start to get punch-a-hole-shaped-like-the-object effects, because the metal is being asked to move faster than the binding forces in the object can propagate the "HEY!  MOVE!" information.  (After all, sound is just the binding forces between atoms in a material moving the adjacent atoms -- and the speed of sound is how fast the message to "move" can propagate.)  From this, we see that WileE Coyote often reached far-supersonic speeds because he often punched silhouette-type holes in rocks, cliffs, trucks, etc.

Around Mach 4 or so, another phenomenon starts -- compressive heating. This is where the leading edge of the ravioli actually starts being heated by compression (remember PV=nRT, the ideal gas law?)  Well, ravioli isn't a gas, but under enough pressure, ravioli behaves as a gas.  It is compressed at the instant of impact and gets hot -- very hot.  Likewise, the impact point on the hull is compressed and gets hot.  Both turn to gasses -- real gasses, glowing-white-hot gasses.  The gasses expand spherically, causing crater-like effects, including a raised rim and a basically parabolic shape.  In the center of the crater, some material is vaporized, then there's a melt zone, then a larger "bent" zone, and the raised rim is caused because the gas expansion bubble center point (the bending force) is actually *inside* the hull plate.  If the hull plate isn't thick enough, then the gas-expansion bubble pushes through to the other side, and you get a structural breach event (technically speaking, a "big hole") in the side of the space-cruiser.

Compressive heating really hits the stride up around 20,000 feet/sec (Mach 4 in steel, Mach 15 in air) and continues as a major factor all the way up to the high fractional Cerenkov speeds, where nuclear forces begin to take effect.

Aside: the "re-entry friction heating" that spacecraft endure when the reenter the atmosphere is NOT friction.  It's really compressive heating of the air in the path.  As long as the spacecraft is faster than Mach 1, the air can't know to get out of the way, so it bunches up in front of the spacecraft.  When you squeeze any gas, it gets hot.  So, the glowing "reentry gas" is really just squeezed air, which heats the spacecraft heat shield by conduction and infrared.  The hypersonic ravioli can be expected to behave similarly.

As we increase speed from the high Mach numbers (about 10 miles/sec) all the way up to about 150,000 miles/sec, not much different happens except that the amount of kinetic energy (which turns into compressive heat) increases.  This is a huge range of velocity, but it's uninteresting velocity.

At high fractional Cerenkov speeds, the ravioli is now beginning to travel at relativistic velocities.  Among other things, this means that the ravioli is aging more slowly than usual, and the ravioli can looks compressed in the direction of travel.  But that's really not important right now.

As we pass Cerenkov 1.0 in the target, we get a new phenomenon -- Cerenkov radiation.  This is that distinctive blue glow seen around water-cooled reactors.  It's just (relatively) harmless light (harmless compared to the other blast effects, that is).  I mention it only because it's so nifty...

At around .9 c (Cerenkov 1.1) , the ravioli starts to perceptibly weigh more.  It's just a relativistic mass increase -- all the additional weight is actually energy, available to do compressive heating upon impact.  The extra weight is converted to heat energy according to the equation E=mc^2; it looks like compressive heating but it's not.

[Here's where I'm a little hazy on the numbers; I'm at work and  don't have time to rederive the Lorentz transformations.]

At around .985 c (Cerenkov 1.2 or so), the ravioli now weighs twice what it used to weigh. For a one pound can, that's two pounds... or about sixty megatons of excess energy.  All of it turns to heat on impact.  Probably very little is left of the space-cruiser.

At around .998 c, the impacting ravioli begins to behave less like ravioli

and more like an extremely intense radiation beam.  Protons in the water of the ravioli begin to successfully penetrate the nuclei of the hull metal.  Thermonuclear interactions, such as hydrogen fusion, may take place in the tomato sauce.

At around .9998 c, the ravioli radiation beam is still wimpy as far as nuclear accellerator energy is concerned, but because there is so much of it, we can expect a truly powerful blast of mixed radiation coming out of the impact site.  Radiation, not mechanical blast, may become the largest hazard to any surviving crew members.

At around .9999999 c, the ravioli radiation may begin to produce "interesting" nuclear particles and events (heavy, short-lived particles). At around .999999999999 c, the ravioli impact site may begin to resemble conditions in the original "big bang"; equilibrium between matter and energy; free pair production; antimatter and matter coexisting in equilibrium with a very intense gamma-ray flux, etc.[1]

Past that, who knows?  It may be possible to generate quantum black holes given a sufficiently high velocity can of ravioli.

     --Bill

[1]According to physicist W. Murray, we may also expect raining frogs, plagues of locusts, cats and dogs living together, real Old Testament destruction.  You get the idea... 

[ahedderick]

PV=nRT

Sobbing quietly, in a restrained and dignified manner, onto pg 408 "Ideal Gas Laws"

(I can do this, don't worry. I just don't Want To)

[carrcrashhearts]

everything makes sense except PV=nRT

[materialsscienceandengineering]

Ideal Gas Law

In 1834, Benoît Paul Émile Clapeyron stated a combined version of previous gas laws (Boyle's law, Charles's law, Avogadro's law, and Gay-Lussac's law) known as the ideal gas law or the general gas expression. Though it can be used in many situations to describe the behavior of real gases, it is a theoretical equation relating pressure, volume, temperature, and amount of a substance.

The most common form of the equation is PV = nRT, with P = pressure, V = volume, n = the amount or number of moles of a substance, R = the ideal gas constant, and T = temperature. However, it can also be stated using Boltzmann's constant and/or Avogadro's constant, as well as a variety of other forms.

Sources/Further Reading: (Image source - Wikipedia) (Khan Academy) (LibreTexts) (HyperPhysics)

[glitchlight]

dirt facts for the columbia river basin? 🤲

godddd the PNW has such interesting geology. There's a surprising amount of volcanic geology within the united states, but the majority of it is west of the rockies, and no place else is that more common than in the PNW. Geologists in the PNW are welcome to correct me, but as someone whose mostly worked in very predictable glacial geology or residuum from common marine sedimentary strata (limestone shale siltstone repeat repeat repeat -- hey karst!), my overwhelming impression of the PNW has been a region dominated geologically recent cataclysms which have dramatically reshaped the landscapes, and the Columbia River Basin has at least three different impacts that effect soil development as a result: the columbia flood basalts which stem from the yellowstone hot spot, the missoula floods at the end of the last ice age, and the influence of volcanic eruptions on the surrounding area from the cascades and the yellowstone hot spot.

The main thing I find interesting here however is one that is a little less than remarkable given the cataclysmic history of the region, and is far more mundane: the disparity in the landscape on either side of the cascades.

This is a somewhat remarkable observation on a flat image. In the space of 60 miles, the entire landscape transitions from a semi-arid landscape to one overflowing with greenery and vegetation. Driving west on I-84 produces landscapes that wouldn't be out of place in the rest of the arid west, Nevada, Idaho, Montana.

Of course, that is an illusion created by a flat image. Naturally, there is an entire mountain range in the way.

The imagery undersells it: this looks like a low range of hills, all too familiar to those of us who live out east and drive over rolling hills every day. The Columbia River Gorge, seen here curving off to the right beyond the Dalles, cuts deep through the Cascades and the high plateau built up by, you guessed it! All! Those! Flood Basalts!

This dramatic difference isn't just due to elevation changes, but is largely due to the infamous rain shadow effect that occurs in much of the PNW.

Brief detour to physics: pressure. In gasses, if temperature increases, pressure must increase (provided volume remains constant). If you've had a half an equation hanging out of your brain for the past 10 years from chemistry class, it's probably pV=nRT which describes this exact relationship. Anyways: if you take a bunch of moist air coming off the Pacific, and have winds blowing it up a hill, because it rises in elevation, atmosphere pressure decreases, so temperature of the front decreases as well and you get the PNW's infamous eternal rain. This entire effect is known as orographic lift.

And IN SPITE OF THIS! The soils aren't really all that different on either side of the range! They're primarily different in terms of weathering!

The agricultural soils to the east are rather plain, slightly developed soils which consist of drifts of dust deposited over thousands of years onto cracked basalt (floods again!). The same materials are present to the west, but because it rains so much more, they're much more developed, enough that silica, you know, the stuff Sand is made out of, has weathered and recemented within the soils, creating what's called a fragipan -- almost like a natural type of concrete!

Thanks!

[erbiumspectrum]

Hi! Do you have any tips for studying chemistry? For some reason I cant seem to get all the formulas in my brain.

Hey!

My unhelpful but still favorite advice for shoving formulas into one's brain is to understand them 😅 A purely memorization-based approach is very bad for chemistry.

If the problem seems to be particularly understanding/ remembering formulas:

Ask yourself if this particular formula is just words turned into numbers and mathematical symbols. I think it may not work for everyone, but for example I found it easier to remember the literal definition of pH that is "the negative decimal logarithm of hydrogen ion concentration" rather than "pH = -log [H+]" bc otherwise I'd keep forgetting about the minus sign.

Check if you find deriving a formula from another formula easier than just memorizing it. Again, my personal example is I hate memorizing things so much I never really bothered to remember the equation that describes Ostwald's law of dilution - bc I knew I could easily, quickly, and painlessly derive it from the equilibrium constant for concentration + degree of dissociation (and I've done it so many times now it stuck in my brain anyway).

When all else fails, I turn to mnemotechnics. To this day I remember that Clapeyron's equation goes pV = nRT because many years ago someone on the internet shared a funny sentence whose words start with these 5 letters. The sillier the better.

If the issue is with chemistry in general:

Take it chapter by chapter. Chemistry, like most STEM subjects, is just blocks of knowledge upon blocks of knowledge. For example, if you want to learn electrolysis, you need to understand redox reactions first. Try to identify where the struggle begins and work from there.

Once you've picked a topic you want to work on, follow the reasoning in your textbook. If you get stuck, that might be a sign you're simply missing a piece of information from a previous chapter. If an example comes up, try to solve it along with the tips in the textbook.

If anything remains unclear, it's usually not the best idea to just leave it and move on. If the textbook becomes unhelpful, turn to the internet or maybe a friend. Otherwise, the next chapter may just turn out to be needlessly confusing.

Practice problems practice problems practice problems!! And not just the numerical ones. The theory-based ones where they ask you about reactions, orbitals, the properties of the elements etc. are important too.

Choose understanding over memorizing whenever possible.

Try to look at the big picture: the way certain concepts are intertwined, how one law may be a logical consequence of another law you learnt before, why some concepts are taught together, why you had to learn something else first to get to what you're studying now. Again, as an example, I think it's particularly fun to see towards the end of ochem, somewhere around the biomolecules: you need to integrate your knowledge of aromatic compounds, ketones and aldehydes, alcohols, carboxylic acids... Stack new information upon what you already know.

Study methods I'm a big fan of: spaced repetition, solving past papers (anything I can get my hands on tbh), flashcards for the things I absolutely have to memorize, exchanging questions and answers with a friend, watching related videos.

If by any chance you end up taking pchem, I have a post for that specifically.

I hope you can find something helpful here :) Good luck!

[gobletcell]

I can't stand chem anymore (mini rant)(´°̥̥̥̥̥̥̥̥ω°̥̥̥̥̥̥̥̥｀)

I am now regretting all life choices, from the moment I was born to today, that lead to me taking this horrible subject. This is the millionth time going over hybridisation and I still don't get it. The only sigma I understand is the one on TikTok and that pi is 3.14159365589.....

Everything I've learned in the past is now a lie. What do you mean aluminium chloride is not ionic?! Wdym I can't use PV=nRT in every situation? Basically every rule I previously learned is useless. Chemistry has more exceptions than french and I am not having it.

There is this asteroid that it is said to have a 2% chance of hitting earth in 8 years. I am manifesting that it will hit us before my chemistry finals.

Should've gotten business instead :,)

[liviathonnn]

Since I’m obsessed with formula one and the witchcraft that is science I thought I’d share some fun facts I picked up from the fp2 Mexican gp broadcast. Physics isn’t my specialty tho so please correct or add on!!!

Since the track is at such high altitude the air pressure is lower, which causes:

hotter brakes (and everything else that relies on airflow for cooling) because every bit of air that’s taken in through the cooling vents has less air molecules to whisk heat away from the brakes, so it’s less efficient

cooler tires, and now I’m not super sure on the reason for why but my theories are 1) fluids gain temperature as they’re compressed, which has a significant effect on water in the deep ocean so maybe it also affects the tires? Less pressure = less temperature gained from compression. See also ideal gas law (PV=nRT), but I highly doubt tires fit the conditions and that the effect would be significant And 2) which I’m now realizing is actually just theory 1 in a trenchcoat, lower pressure air should be worse at holding temperature than higher pressure air because idk the vibes are logical since high altitude areas are basically always colder than sea level

less downforce, which on the surface makes sense, there is literally less air forcing the car down. There’s probably something about ground effect that changes too, like the suction bit the cars do as they turn, but that is very much witchcraft to me so eh?

less drag! Which is why the fastest straight in the calendar is at the Mexico circuit. This one also seems logical, less air molecules/amount air are in the way of the car so the amount the car is slowed by air resistance is reduced.

I’m probably drastically simplifying physics but hey! Aerodynamics and thermodynamics are bitches so they deserves it! Credit to the queens of science on the f1 commentary squad Ruth Buscombe and Bernie Collin I could listen to them for hours