An Actually Good Explanation of Moles

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Moles (in chemistry) are really clever and useful. The definition involves a really big number called Avogadro's Number and on its own is really unhelpful when trying to understand what the Mole is actually for! The best way to get your head around this unit (Mol) is to look at the problem that is solves. Along the way you'll find out about Atomic Mass Units, isotopes and some dodgy chemical equations!
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[@SteveMould]

This week should be a short video. This was supposed to be a short video. But then it turned out to be long. Hope you like it. And I hope you now understand Moles if you didn't already. The sponsor is Brilliant.org. The first 200 people to sign up at brilliant.org/stevemould/ will get 20% off an annual subscription that gives you access to the full archive of Daily Challenges and every single course

[@SteveMould]

@@carnsoaks1 volume of a mole of gas in liters?

[@VindicusVore]

I understand Moles better now after this, struggled with the concept all through schooling, as Chemistry is my weakest science subject. Physics was (and is still) is where my grasp is strongest, especially when leaning into theoretics and hypotheticals. (I have far too much time on my hands, so I spend ridiculous lengths of time just wandering my mind palace, doing thought eperiments)

[@JesusisJesus]

Steve Mould I clicked on it thinking you’d be talking about a little furry animal. At 10:00 when you mentioned carbon, Cody got hungry.

[@surelynottrue3894]

@@SteveMould H referencing for amu existed afaik, instead of C. They changed over later

[@andrewedis9907]

I've struggled with this concept myself so Thankyou Steve

[@kedarjoshi1706]

By making this video, Steve Moled

[@HassanSelim0]

Steve needs to read this 😂

[@matthieugross80]

You just had to do it. Didnt you?

[@RinkuKumar-gm5ti]

haha atti utta

[@FahadAyaz]

👏

[@FahadAyaz]

@Paul john Wow, what's wrong with you?

[@mesaprime4368]

"I have a drawer in my house that has half a mole of cables in it" thats what we call a premium joke

[@yuvalne]

Yup

[@norikitsune]

Someone explain im dumb

[@Maazin5]

Rai Rai Steve claims he has half a mole of cables in his drawer, which is still an impossibly large number of cables (300 sextillion). If you have a lot of charging cables in your house it'll seem like that.

[@98dizzard]

A drawer? I have 4 small storage boxes and 2 crates. Surely if a drawer is .5 mole, I must have at least 7 moles of cables.

[@boomfiziks]

On Mole day, I post a picture of my self on the various social sites, holding up a sign. The sign reads, “If I get one mole of likes, I’ll give every one of my students an “A” for the entire year.” Last year was the closest they ever got to one mole...just 2.17E-20% of the way from reaching one mole. 😜🤣

[@davidguthary8147]

Fun fact: because of the importance of the mole in chemistry, it has its own unofficial holiday similar to Pi Day. Mole Day is celebrated every year on October 23 from 6:02 AM to 6:02 PM, in reference to Avogadro's Number 6.02*10^23.

[@cyrilio]

Me must have a Mol day video every year from now on then.

[@liam3284]

if this is not true, it should be.

[@toonedin]

When Chemists express geekery!

[@ThomasTheThermonuclearBomb]

We also need an e day, July 2nd (or February 7th for you Americans)

[@mojeimja]

you mean Avocado number?

[@blackmber]

Funny story about Beryllium Oxide. I dressed up as the compound for halloween with someone I dated - we each wore a t-shirt with the chemical symbols and some pom-poms to represent valence electrons. I think the ratio of our weights was about 16:9, because when we went rock climbing and I was belaying him, the rope suddenly lifted me off the ground and I ended up halfway up the wall while he dropped toward the ground. But the reason we decided to dress up as BeO is because of its incredibly strong bond, which I hoped would be a sweet metaphor for our relationship. Instead I discovered it's very toxic and hard to break up.

[@avranckneupane6717]

wtf hahaha

[@hamarticdownfall9919]

This is either the funniest chemistry joke I've ever heard or it's just sad irony

[@CaioAletroca]

"Very toxic and hard to break up" You mean Beryllium Oxide, right? RIGHT??

[@tomasbeltran04050]

@@hamarticdownfall9919 IRONy

[@IssaalaaRacing]

@@CaioAletroca I hope so 😭

[@calebcole7480]

that 16:9 joke was good

[@davidsmets99]

in a very terrible way but yes

[@josephjoyce2760]

Somone please explain it to me

[@RafidW9]

@@josephjoyce2760 16:9 is the aspect ratio of hd screens, and the ratio is called widescreen ratio.

[@hotdogskid]

The face he made was brilliant too lol

[@terablast]

So was the "half a mole of cables in a drawer" joke!

[@screwaccountnames]

How many atoms in a guaca-mole? Avocado's number!

[@jeffcarr392]

That must be a .... . Holy. . Moley . I'll get my coat! 😆😆😆😆🙄

[@mrpenguin2083]

Jeff Carr the read more function of my youtube is broken what’s the punchline

[@screwaccountnames]

@@mrpenguin2083 Avocado's number

[@orangus01]

@@mrpenguin2083 "Avocado's number!"

[@nocullough]

Underrated comment^^

[@bielsabas4407]

You make learning science, physics, and chemistry so "not anxiety inducing". Thank you for the work that you do! Your videos are so calming to listen to.

[@ViniSocramSaint]

Maybe that lack of anxiety comes from not being in school anymore. There was intense pressure of "becoming a Mcdon*lds' worker" if you get it wrong in tests and looking "dumb" for showing lack of a grasp of the concept, meanwhile there was stress for being a "teachers' pet" and showing eagerness to learn about it, also, teachers could not wait for us and we had to take the concept as fast as possible - if possible - or they actually do not know the thing and beat around the bush or we got stranded on books that talk of "alien lands". Here we are free to just take it in, on our pace, from a reliable source using simple language, with 0 pressure to have to prove we got it. It's just pure curiosity

[@manthansharma4835]

And that's how learning should be... It should be achievable by most of the humanity ..

[@bestcreations4703]

I am a stem tutor and have run into a situation where I’ve had to explain why we use moles to a student who was getting frustrated with the idea of it. This video helped me put some thoughts into words but I also have found an explanation that I quite like to give. In the video, it is repeated that avagadros number is just a counting number used to describe a specific quantity of things. Thats a long winded explanation that some may not easily get. I love to compare it directly to other familiar numbers just like that for example my favourite is to use a bakers dozen. We all know a bakers dozen is 13. It’s just a name for a very specific number of things and can be used anywhere you like. Avagadros number is the exact same thing but designed to describe such small things that to have an amount on any relative human scale you need an unbelievable amount of them. Using avagadros number as the base unit lets us talk about quantities of atoms without needing to resort to long winded definitions or unreasonably large numbers. A good example of where we use that exact same logic is in definitions of hours. An hour is sort of arbitrary, the base unit we typically use for time is seconds, so if we wanted to talk about an hours length of time using the base unit we would have to specify 3600 seconds. An hour just makes it easier to use on larger timescales. Another example but on the opposite side of size is the unit of solar mass or astronomical unit which represent a mass approximately equivalent to that of our sun, and a distance approximately equal to that between the earth and the Sun respectively. They are just a specific quantity of units which help in talking about and working with the units on larger scales.

[@jasonreed7522]

I use the joke/explanation that a mol is just a chemist's dozen, and its exact value is simply chosen for convience. (Converting the atomic mass of 1 partical to the mass in grams of a sample of those particles makes it much easier to measure samples out in a scale in realistic quantities for humans) And it has a friend i learned about in thermodynamics, the pound mol because of course the imperial system needed to continue its complexity past the legacy units that make sense in context of what their original purpose was. (Its actually a great idea to dive into the history of units themselves and what they mean. For instance american wire gauge gets physically smaller as the number goes up, this is because its the number if times the wire is ran through the standard die. And for really big wires we use circular mills which are a unit of area equivalent to a circle of radius of 1 milli-inch which sounds stupid until you realize it moves π inside the unit so the formula is just square the radius and use the round number. Stupid units exist for a reason and once you know it they go from stupid to genius.)

[@jaimelapolitique349]

No, just saying 'it's like a dozen" is not a good enough explanation! It's just as confusing as trying to mix H with F by relying on grams alone ... because it does not explain what is the truly confusing characteristic of moles: the one thing that the equations DO NOT DISPLAY is that you are just expected to know the particular atomic mass OF EACH DIFFERENT substance involved, and take that into account every time BEFORE you weigh up anything! When you perform 'normal' (non-chemistry related) operations, everything you need is spelled out, AND it always works the same like: 12+8=20 ... you do not have to keep in mind stuff that is not written and that would make your equation no longer true, because '12' (or if you prefer, a dozen) of a certain substance would not mean as much as 'a dozen' of a different substance ...

[@angelmendez-rivera351]

@@jaimelapolitique349 It solves the probem just fine, though. A dozen of eggs has a different mass than a dozen of apples. Same concept. They have different 'dozenal masses.'

[@BCThunderthud]

I think the atomic weight in grams is easier to grasp, but the story of how they proved it was a constant and calculated it is fascinating.

[@aquacuber505]

A bakes dozen is NOT 13, it is 12.

[@jeffreybernath6627]

I love that Steve can't say "ounces" with a straight face, like it's the most ridiculous unit he could think of for this example.

[@lukesalazar9283]

@@barongerhardt or butts. That's a real English unit of measurement

[@vincentvega5686]

@@barongerhardt ha! that's a trick question. there are no moles in a butt just hamsters. lol

[@mariojoia1337]

Unce unce unce unce unce, looks more like beatbox than a measure.

[@DieFlabbergast]

Hah! You science nerds! Give you a centimeter and you'll take a kilometer.

[@guynorth3277]

@@barongerhardt; LOL

[@CodeKujo]

"One micro Mole of sand grains on the earth" - wow, nice example just how big a Mole is / how small atoms are.

[@vdinh143]

and how many cables we hoard

[@Tomwesstein]

Or how few grains of sand there are..

[@The268170]

I have 6*10^23 particles in my butt. At least.

[@subliminalvibes]

Nice! 👍😎 ..also, remember that each grain of sand has several times the distance of the moon [from Earth] between them before you even reach their electron shell! 😮

[@antonhelsgaun]

@@subliminalvibes bruh

[@CharlesBurchill]

Thanks - my dad was a chemistry professor for about 30 years and it drove him nuts that my high school teachers (and others) got caught up in the size of a mole rather than the purpose - I think he would have wished your video was available back then.... :-)

[@ferretyluv]

My teacher explained it to me as being the same as saying there’s “a dozen” or “a gross” of something. She also demonstrated it by showing us a mole of water, which was like half a jar-full of water. I don’t know why out of all the concepts in chemistry this was the easiest for me to grasp, especially when I have trouble with abstract concepts. Dimensional analysis took longer for me. But the mole, I guess just by seeing a jar of water, it clicked. It also helps to see the periodic table with the number underneath each element. XKCD also has a great What If about what would happen if you had a mole of moles.

[@flyingpenguin7622]

I loved that mol of moles chapter haha

[@sarahlee1696]

Isn't a mole of water 18 ml? That's a lot less than half a jar.

[@ferretyluv]

@@sarahlee1696 Depends on the jar size. I think she was demonstrating molarity, to be specific, so it was grams per mL.

[@skilletborne]

@@sarahlee1696 I own several 5ml jars. I can accept the existence of a mythical 40ml jar.

[@The757packerfan]

This is exactly why I did NOT understand moles. Because it's NOT like a "dozen". A dozen is ALWAYS 12, no matter the thing you are counting. A mole of Hydrogen is 1 gram, where a mole of Nitrogen is 14 grams...

[@PWJB]

I have had great success with:"Hey you know how 12 eggs are called a dozen? Same thing but not 12 but 6x10^23 instead"

[@jessetheunending9357]

Yet this explanation never made enough sense to me in school. It still doesn't help me understand completely. Maybe if I watch a mole of Steve Mould videos...

[@PWJB]

@@jessetheunending9357 To be fair, I didn't really get it for a long time either, because no teacher I had was able to convey that It's basically only a short way of saying "A pile of 6x10^23 molecules of the same compound/element" for the purpose of being able to calculate ratios for reactions a lot easier. Also watching a mole of videos sounds like it would take a loooooong time ;D

[@peterhall4086]

A chemist's dozen.

[@markknoop777]

But that doesn't explain why it's that number

[@SECONDQUEST]

@@markknoop777 aight but did you watch the video? Avogadro is dying

[@CroomTM]

So a mol is like saying "a dozen" of something?

[@billiumdollars]

Exactly :) I thought this video was going to be like ... its like a dozen... goodbye :)

[@lexicoll1]

Yes... which begs the question why it is an SI base unit.

[@karolakkolo123]

@@lexicoll1 because the mole measures the quantity of substance... not mass of substance. Both are useful in their own contexts, so both deserve base units. Imagine if instead of having a base unit like the mol, we had to report the quantity of substance using unit-less, but precise number of atoms in a substance. That would be.. impractical

[@jasonpatterson8091]

That's exactly right, but when you're counting atoms or molecules there are so stupidly many of them in even the smallest amounts of anything, counting them by the dozen is pointless. You need a stupidly big grouping number to count stupidly many things conveniently, and thus 6.02x10^23. I could say that a bottle of water holds 19,800,000,000,000,000,000,000,000 molecules of H2O, or that it contains 1,600,000,000,000,000,000,000,000 dozen molecules of H2O, but both of those numbers are just too big for us to really understand and they're awful to write down. Instead I can say that the bottle contains 33 moles of water molecules and it is the kind of quantity that we can all work with. In practice we drop the word "atoms" or "molecules" almost immediately (ex: 33 moles of water) and that tends to confuse students who never quite mastered the concept.

[@DrakonIL]

It's like a dozen, but it's bigger than a dozen. It's also bigger than a baker's dozen.

[@MikeSpille]

Hahaha - “I have a drawer in my house with a half a mole of cables in it”. I love it.

[@thunderb00m]

Those are rookie numbers to be honest

[@bionshelden5128]

Placing moles in the same category as the offside rule was *brilliant* ! So incredibly true!

[@thenasadude6878]

My high school Chemistry professor must have been really good because this is exactly how she taught us about moles :) She was strict, but she also really loved her science

[@jasonpatterson8091]

Explaining moles by analogy to the dozen has always worked for me. The only trick is why 6.02x10^23, and that happens to be (approximately) the number of protons in 1g of protons.

[@HappyBeezerStudios]

And a dozen is also an estimate. There are 13 in a bakers dozen.

[@godsofthesingularity8308]

Exactly. I don't know why everyone doesn't start with "the number of nucleons that weigh a gram." That's it. That's the actual definition. Why do they teach it any other way?

[@carultch]

@@godsofthesingularity8308 Because that's not the definition. In general, it is approximately true that this is the case, and for small elements, it is very close to being accurate. But it is not true for the particles in their isolated forms, or much heavier elements. Other nuclear factors come into play, which is why the atomic mass doesn't necessarily equal the mass number, even for a single isotope. At one point, we defined the mole such that exactly 12 grams of pure carbon 12 would be exactly 1 mole of carbon atoms. This meant that each nucleon on average had a mass of approximately 1 amu. As of 2019, we fixed Avogadro's number to 9 significant digits, to define the mole.

[@stephenspackman5573]

@@carultch But it's the informal definition, the originally intended definition, the practical definition, and the place the intuition comes from-in short, the explanation. Just as the _explanation_ of the second is still that it's 1/60 of a minute, the _explanation_ of the gramme is that it's the mass of a millilitre of water, and the _explanation_ of the metre is that it's 10^-7 of the distance from the pole to the equator, even though the _formal_ definitions of everything have shifted over the years as we have needed more significant figures.

[@gameit9970]

Well yes but actually no

[@mayaluna9479]

best explanation I’ve ever seen 😭 literally have not understood this concept for years and I now feel enlightened

[@GuyJustCool]

Steve, thank you for what you do. Your ability to explain is great, you are charismatic, and you have great sense of humor. I binge your videos for a while now!

[@Sublimeoo]

"But that's impractical" has the biggest understatement in history surely

[@agb2557]

“... and it’s why I call this chemical the wide screen chemical **wheeze** 🥴”

[@StereoSpace]

You have a similar teaching style to my first physics instructor. He often started with science history, and worked up to how we got such and such an equation. It was fascinating.

[@Alexa_Kelley]

That was fantastic and I genuinely wish this video had existed years ago when I took chemistry with a rather awful teacher who couldn't properly convey to me what a mole was. TY for sharing and making this.

[@majorfallacy5926]

"How did you blow up the lab?" "Steve told me to react 10oz of hydrogen radicals with 190oz of flourine" Edit: small clarification for 8:15 - the bonded nucleons have a lower energy than unbonded ones. So the bond has "negative mass", i.e. the particle is lighter than the sum of its parts. (the phenomenon is called mass defect)

[@jerry3790]

The reason it blew up is because you used oz instead of grams

[@Morbacounet]

The reason you gain mass when you break the bond between the particules is that you have to hive them energy to separate them. And that energy has a certain amount of mass because of E=mc2. (I didn't realize this immediately when I studied chemistry).

[@PetraKann]

....only if you weigh each individual 'physical' part separately without them being in a coupled or interactive state. The particle is not lighter than the sum of its parts (not if you include ALL of the parts)

[@wbfaulk]

How much flourine should I react with my butterine, sugarine, and eggine to get a really good cakeine?

[@PetraKann]

@@wbfaulk 0.86?

[@sbeveridge]

I passed O Level chemistry in the 1970's. As I remember, the word 'mole' is short for 'gramme molecule', which kind of reminds you of the definition.

[@EebstertheGreat]

Wikipedia claims that the English word "mole" comes from the German abbreviation "Mol" for "Molekül," which of course means "molecule." I assume the e was added in English to aid pronunciation.

[@iabervon]

Something I never thought of before: you take O levels when you're 16, but you really ought to take them 8 hours and 45 minutes before your birthday, when you're 15,999.

[@andrewbergspage]

@@rebeuhsin6410 but molecular weight uses the same definition based on carbon-12, so yes, they are equivalent. Actually old textbooks might have used the definition based on oxygen-16, so perhaps not exactly equivalent to today's moles, but exactly equivalent to moles of their day.

[@prschuster]

I recall mole to mean "gram molecular weight", that is the weight in grams equivalent to the mass of one molecule in amu.

[@aperinich]

gramme molecule = gramm molekul = abbreviated to Mol because no "gram molecule" variant could be shortened to "gram" (already taken). "Mol" ("Mole" in English) would have to suffice.

[@ArnavSingh-im5bj]

Man! U are a blessing. No one taught me moles like this. Thank you so much for your hard work. I really can't thank you enough. Please keep making videos with such a level of simplicity and fun

[@readmydescription5533]

Punjabi dhola

[@clouds7]

Thank you so much! I've been struggling in class for days trying to get this concept. It feels so good to finally understand it :) Hope I do well on my assessment tomorrow.

[@nekrosis4431]

12:33 "I accidentally know quite a lot about AI." Yeah that happens to me a lot. Like I just watch this random dude on KZbin and now I accidentally know more about chemistry.

[@TechSupportDave]

Same but in my case, I know an excessive amount about Relativistic quantum mechanics and general relativity by accident. My knowledge just somehow accumulated over many years from reading bits and pieces of it on the internet.

[@AJMansfield1]

10:00 ignoring the that the _original_ original definition was actually 16 grams of atmospheric (not isotopically-pure!) oxygen. At this point in history, the concept that "atoms" were even a thing was only just starting to be taken seriously. Nobody had any idea "how many" atoms that might be, or had even a concept that atoms might be made up of "subatomic" particles like neutrons and protons. That's why, even today, oxygen is still 15.999. When they finally figured out that subatomic particles were a thing, and that individual oxygens could sometimes be only 15 amu rather than 16, everyone was already using the oxygen standard mol for everything, including international trade. It was only dumb luck that carbon-12 happened to be almost exactly 12 grams per oxygen-mol, close enough that the two could be swapped out without anybody complaining too much.

[@warmCabin]

> At this point in history, the concept that "atoms" were even a thing was only just starting to be taken seriously. If that's the case, how were people conceptualizing the mole? Actually...how were people conceptualizing chemistry in general?

[@AJMansfield1]

​@@warmCabin Proust's law, aka the Law of Definite Proportions, observes that in any given compound, the mass ratio between different elements is fixed - always the same for a given chemical, even if it's prepared a different way or from a different source. Even if you don't subscribe to some silly notion about everything being made up of tiny billiard balls, it's easy to experimentally see that 18 grams of water always decomposes into 2 grams of hydrogen and 16 grams of oxygen. In fact, if you compare those elemental ratios between _different_ chemicals, and seeing that, while you wouldn't always see a ratio of exactly 2/16 hydrogen to oxygen in everything containing either, you _would_ always see a simple _multiple_ of that ratio - you might have 1/16, or 3/16, or 4/16, or 1/32, or so on, but not 1/15 or 1/17. And if you then look at other elements, you'll spot other numbers that seem to keep appearing in ratios involving _those_ elements, and arrive at the idea that there's a sort of _equivalence_ between 1 gram of hydrogen, 16 grams of oxygen, 35½ grams of chlorine, 65⅓ grams of zinc, and so forth. Following that same line of reasoning then, it might make sense to start using these baseline equivalences and dividing the masses of your chemicals by them -- essentially, converting your mass-centered notion of quantity to a stoichiometry-centered notion of quantity, i.e. a mole. en.wikipedia.org/wiki/Law_of_definite_proportions en.wikipedia.org/wiki/Equivalent_weight en.wikipedia.org/wiki/Mole_(unit)#History

[@andrewrobertson444]

"It was only dumb luck that carbon-12 happened to be almost exactly 12 grams per oxygen-mol" Well, if it hadn't been, it wouldn't have been chosen as the standard.

[@toonedin]

What at awesome explanation! I finally understood at 50 what eluded me since 15. And you, Sir, have earned my subscription to your channel for that. Thank you.

[@maya_unplugged]

Thank you so much! Back in school my teacher wasn’t able to explain moles…😮 I would never expect it so easy, the way you did. 🙏 I will never have use for that information in my life, but I feel much better now! 😂

[@recinbersvoice8802]

Can we put “BeO: the widescreen molecule” on a shirt?

[@abhijithcpreej]

"A chemist trying to explain moles" is the funniest thing I will ever see. Goodbye world

[@jc-pj3nh]

Best video ever. You just simplified the most confusing terminology used in chemistry. Had a chemistry professor in college who taught the class assuming every one had a PhD in chemistry. Miraculously passed the course taught by someone who should never have been hired to teach. He was paid $1 a year and as far as a student that was all he was worth.

[@nivok7]

Years of chemistry in school and half a year of chemistry in university and not once did someone explain it as easy as this video. They all stuck with the Avogadro's number and that's it. Thank you 🙂👍🏻

[@13krava]

I’ve been watching you for a while now Steve. And I have to say that your channel is consistently one of the best ones on youtube. Your positivity, humor, eloquence and charisma all make each one of your videos amazing. I especially love how you take something which seems mundane and boring and show how interesting it is. You are a perfect example of how we can find beautiful and interesting things all around us. Anyway, I just wanted to say this, I don’t usually comment on youtube. Keep up the great work.

[@LukaszSebastian]

Somehow the concept of mole was alway really easy and straightforward for me... Just like a dozen, but bigger...

[@Wilczurban]

Yup. Same for me. I think, that is true, because I was used to use the old names like mendel (15 pieces), kopa (60 pieces) or gros (144 pieces). Somehow one more name "mole" was easy to digest.

[@JNCressey]

I was very happy when I found out pH is the negative log of the concentration of H+ ions, it made things so much more straightforward. A few years before I'd asked my highschool chemistry teacher what pH means and they said no-one really knows - well that was a lie, turns out they just didn't know.

[@EebstertheGreat]

@@Wilczurban In English, 144 is spelled "gross," and 1728 is a "great gross." There were a lot of these in use in the Middle Ages. In particular, "hundred" was just another unit of count, and it differed from place to place. The most common values for a hundred were 120 (when reckoning by twenties) or 100 (when reckoning by tens), though other values were used too depending on the industry. This variability is still reflected in the British "hundredweight" of 112 pounds (chosen because it is exactly 8 stone of 14 lbs. each), from which is derived their "long" ton of 20 cwt = 2240 lbs. America by contrast used a hundredweight of exactly 100 lbs., giving it a "short" ton of 2000 lbs. Of particular importance to the "long hundred" (or "small gross") of 120 was the "score," with a value of 20. The score had already fallen out of use by the time Lincoln gave his famous Gettysburg Address, but he used the word anyway to develop a sense of gravity and historicalness. The score is also historically relevant to the names of numbers in France, where 80 is called "quatre vingt" (four twenty).

[@ThePandafriend]

@@JNCressey The high school teacher oO? I mean if you'd have said "grade school teacher" sure, I doubt that a grade school teacher would explain the concept of logarithms to children so early, we learned just that the pH-Value is "how acidic" something is. I asked what it stands for and the teacher said that it's hard to explain without advanced knowledge in maths. I asked my parents and they had a hard time explaining it too. I mean I didn't even know what "to the power of x" means, even though I saw it in some articles in the magazines they read. There are tons of calculations where you need the amount of protons. Especially in biology. How is it even possible to get into that position without that knowledge?

[@andrewbergspage]

@@ThePandafriend unfortunately schools are not always funded such that they can attract the best talent. Many high school chemistry teachers studied biology or geology or some other branch of science to become a "science" teacher, to which the principal says, "we need someone to teach chemistry - you're a science teacher. Here's the textbook." Good chemistry teachers are hard to find for the same reason that good programming teachers are almost impossible to find. It's a rare person who will take half the pay in exchange for the ambiguous reward of bettering society.

[@kaydeningham4148]

I didn’t know what kind of moles this video would be about, but Iwasn’t disappointed to find out! Really interesting video

[@Omaryllo]

What clicked it for me was this 6:56 Brilliant explanation. What I struggled most with in chemistry was the calculation the other way around. You know you need x moles of sodium chloride, but how much is that exactly? That explanation is perfect. I could just literally replace "mole" with "atomic mass of sodium chloride, but in grams" and the math would just naturally fall into place. It's a natural language phenomena that is confusing in mathematical notation (1 mol of x = 1 gram / mass of x). We're not taught to do math with units in school properly either so that doesn't help

[@stumbling]

The Offside Rule: When a mole comes between another mole and his mole hole goal (excluding the mole-hole-goal-keeper) the ball cannot be passed to said mole.

[@jessetheunending9357]

I don't follow football but I love your joke!

[@fewwiggle]

I thought the offside rule was this: Whenever a team appears to score a goal while playing soccer, the player who appeared to score was actually offside.

[@trueriver1950]

@@fewwiggle only if it is the other team.

[@Pooofcomify]

Why does this have such few likes?? This comment is excellent lmao. Not enough soccer fans here

[@bionshelden5128]

@@fewwiggle Shhhh! No one is supposed to know that!

[@Robisquick]

I already know what moles are but I love Steve explaining things so much.

[@user-gm2qc3np5o]

I'm not good at chemistry when I was a high school student. But now, your video brings to me essence and fundermental

[@zeitgeist909]

5:25 - the moment I realised me and Steve were on the same wavelength...

[@Locut0s]

Wonderfully clear explanation :) I never found moles to be difficult to understand when I came upon the idea in chem class in HS though. I think if you are taught it in the context of doing chemistry it quite naturally explains itself, but if you try to come at it from the definition it can be really thorny. This goes for a lot of things in science.

[@blackmber]

Yeah, I first heard about moles from other students taking chemistry while I was not, and it made no sense. Later I did some stoichiometry and had no further questions. Except, I still don't really know how they figured out the number.

[@zephilandevol]

@@blackmber many different people came up with many different way but my favorite was Einstein. He predicted what the number should be by looking at how a liquid becomes more viscous when you dissolve particles in it, I think

[@user-go9fh1lr7b]

omg that's so simplified it took us 1 month talking about the mole, but u did it in 14 min tysm ☺

[@gregntammie]

I really enjoy your videos Steve, thank you for the awesome content. From high school chemistry, 30+ years ago, I remembered Avogadro's number, something to the ^23rd was a Mole and used for calculating reactions, but I have never seen the strength of any chemical advertised as so many Moles. Outside of a chemistry lab, chemical compositions are expressed in %. I have wondered about this often. Why is the hydrochloric acid I put in my pool called muriatic acid and not given in Moles?

[@Chemdawg0360]

Steve Mould is out here giving free chem lectures more understandable than my profs ever could

[@jasonreed7522]

More professors need to understand that if you can't explain something without the math you don't truly understand it. (And this is different from making a bad or unhelpful analogy) Math describes the real world phenomenon, you need to be able to convert the math back and forth with what actually physically happening. This is why one of my favorite peices of math is the Fourier transform because it fundamentally converts anything into a sum of sinusoids, and since voltage in a wire is 1:1 with sound output from a speaker, as long as you were careful with your examples you could easily do the math and then litterally hear it because sound is just sinusoidal waves that stack linearly. It was just such a treat to be able to literally hear the math principles we learned in action and prove that yes this crazy math is real and awesome. (Also the Fourier transform is way more useful and powerful than it has any right to be) Although my first introduction to the Fourier transform was to just jump into the original problem it was meant to solve, which is the heat equation (temperature in a rod over time, and they found a solution for any initial conditions that were a sum of sinusoids (sin(x) & cos(x)) with caveats, and the Fourier transform converts basically any function into those exact conditions making it possible to solve this problem for any real world possible initial conditions.) Of course my professor explained basically none of that history and i had to learn it from KZbin. (3blue1brown is amazing for making math easy to understand)

[@Pants4096]

GAS! GAS!? You didn't talk about gas! One mole of a gas is about a liter, no matter what the gas. That's the part that really blew my mind in high school chemistry.

[@skrrtskrrt1804]

u mean 22,4?

[@unepintade]

@@skrrtskrrt1804 yes and it’s only for ideal gasses

[@TitanTubs]

Mols and orbitals destroyed my love of chemistry. slowly healing it with videos like this, NileRed, CodysLab etc. Ex. Why didn't we talk about magic crystals that release electricity when struck! That is so cool!! Great content Mould.

[@claire8011]

Wonderful! I thought to myself "thirteen minutes is very long, I'll watch a few minutes and that should give me the gist of it" and then I stayed for the whole thing because it was actually making sense. Thanks

[@Jimbodawg]

Hey, Steve! I really like your vids, it seems you really enjoy sharing understanding as much as you do gaining it for yourself. Thanks!

[@tobiasthrien1]

6:18 It seems to me you're suggesting that this is what historically happened (just paraphrased). I just want to point out that for example the "Law of definite proportions" existed before chemist knew about atoms. Therefore the concept of a mole was probably useful even before it was known that one could reduce it to the number of atoms. I hope that makes sense en.wikipedia.org/wiki/Law_of_definite_proportions

[@feelingzhakkaas]

wonderful explanation of NA .... i love it. God bless you for enlightening us

[@przemyslawkroliszewski2322]

How far I can remember my chemistry class at High School, no teacher was trying to explain the MOLE :) It was just the number of particle in "normal conditions". Then i remember that at High School I have had the same confusion when i was trying to understand derivatives. Later I asked this question to the teacher at University - what is a derivative? Ha! it is simple as hell, it is a speed and direction of change :) well... good teacher understands everything and can explain everything. Thumb UP!

[@wilfgordon7704]

woah! my chemistry has been trying to get me to understand this for a year and it only just clicked. thanks!

[@Muonium1]

Fast easy version: A mole is just the ratio between amu and grams.... mostly. the end. but yes, I also did not realize this until long after high school chem because it was taught so confusingly.

[@Wilczurban]

You mean a molar mass. A mole is just a number of things, like a dozen.

[@Srvelis82]

In particular it is the slope of the graph of amu vs grams of all isotopes/atoms.

[@joejoe4games]

@@Wilczurban so just what he said the ration between Dalton (u) and grams (g)... just like 1000 is the ration between grams (g) and kilograms (Kg)

[@0xCAFEF00D]

It was taught so poorly I don't remember the attempt at explaining and my own misconceptions.

[@hydrocharis1]

Yes! If they'd only teach it like this.

[@Geoffsmeg]

Thank you for explaining moles so well, it really helps me!

[@FloatingPhyzzxx]

When I first learned about moles in GCSE's triple science I was absolutely dumbfounded and I though for a good year that they were useless lol I legit said to myself "there is litterally no point you can just use the mass" but this video finally explained to my why they exist lol. But seriously thank you man this helped soo much!!

[@jitmancanth6698]

I knew this stuff like the back of my hand when I did my Chemistry A'Level. Completely blanked it out for the last 20-odd years. Rediscovery is a lot easier than learning it the first time around...

[@noam_segal]

You have the absolutely amazing gift of making everything simpler. I cannot express my appreciation enough.

[@backboardshooter813]

Thank you so much I am doing a STEAM science project and i could not find a useful video defining moles until this one

[@ashimmukherjee5004]

That's an absolutely fantastic presentation on the mole concept - it couldn't be simpler and more comprehensible

[@senorjp21]

A Moule: you know the atomic mass of this thing? Well, that in grams

[@Petar120]

You're wrong, a mole by definition is an animal.

[@samgresty7455]

He so stoopid yes

[@hirvielain9013]

A mole can also be a rat, which is confusing. But an animal nevertheless.

[@danbhakta]

By definition not a skin growth???

[@Frrk]

...why not both? XKCD did a thing about having a mole of moles. what-if.xkcd.com/4/

[@oldcowbb]

no, it is a patch of skin that turned dark

[@ctrlaltdelicious6072]

this was so funny and I‘ll probably never need to watch another mole explanation video now anymore so thanks a million for the headaches and time you‘ve saved us

[@mohamadfazli5575]

Extremely well explained and very easily grassable,,,,well done

[@RageXBlade]

"Chemists like reacting things together" *NileRed has entered the chat*

[@inabothwick6353]

Hahaha

[@Christian-os3kk]

Extractions&Ire as well

[@Jeroco998]

NileRed: "The other day I was taking a calm walk in the countryside and it smelled like hay, so today I tried making phosgene to see how hard it could be¨

[@yogitshankar6348]

@@Jeroco998 That sounds like something he would DEFINITELY say

[@YounesLayachi]

What if Red in NileRed meant... Reduction ? (Redox)

[@eekee6034]

I read the carbon-12 definition first and never had a problem with what a mole was, but this video is a very nice explanation of why the term exists.

[@ashenmorayas1112]

would you mind letting me know what you read having a real hard time grasping this concept

[@eekee6034]

@@ashenmorayas1112 It was a little chemistry reference book, many years ago. I'm sorry I can't be more helpful.

[@wektion]

​@@ashenmorayas1112So, back when we were first figuring out atomic physics, we knew that chemical reactions take some atoms and put them together into a molecule. IE: 1 atom carbon + 2 atoms oxygen = 1 carbon dioxide (CO2) molecule. BUT, the atoms (and the molecule) weigh different amounts, so it's not that 1g C + 2g = 3gCO2, instead 1g C + 3.2g O = 4.4g CO2. There is a ratio (different for each kind of atom/molecule) between number of atoms of an element and mass of those atoms. Now we knew that carbon-12 has 6 protons and 6 neutrons for 12 total nuclear parts. Back then we assumed that protons and neutrons had to the same mass (they don't actually, but it's close enough) and that electrons didn't contribute to an atom's mass. So we thought if you have 12g of Carbon-12 that would be 1g per proton/neutron, so we called that a mole. And that's what a mole was, the number of particles in 12g of carbon 12, the exact number of which is Avogadro's number, but that's much less important. Now with that defined, would could figure out the atomic weight of each element so that we could write our chemistry like 1C + 1O = 1CO2 instead of having fiddly mass numbers. Now, way after the fact, we know that protons and neutrons have different masses than each other, and that electrons contribute a small bit to mass, so while a mol is still 12g of carbon-12, it isn't actually exactly 1g of protons (but it is **really** close). But in chemistry, the exact number or reason for what a mol is doesn't matter, just like it doesn't matter that a gram is 1.475521399735270×10^37 h•hz/(light-second^2). We just know that it is an agreed upon number of atoms (or molecules) which we know how to find the mass of using atomic weight.

[@jeffpearce8748]

The best video by far on this subject. Thankyou!

[@Squishen]

I have a chemistry test tommorrow and you just saved my life omg

[@intjonmiller]

Ever since I aced inorganic chemistry 20-odd years ago I have been able to recite Avogadro's number, but I had long since forgotten what it actually represented (why that was the number). Thanks for the excellent reminder, taught better than it was back then!

[@davidnotonstinnett]

The craziest thing about Moles is that it isn’t named after a person.

[@mikymuky1171]

I already knew I knew what a mol of a substance was, but I'm glad to say that I can now teach it with more ease in the future. Thanks Steve!

[@CaseyCarnnia]

I enjoy your content completly. Thank you for you.

[@drd1924]

This was such an excellent explanation, plus you tied it in stoichiometrically!!! Subscribed!

[@simonlinser8286]

I never had trouble understanding it! It's the chemist's dozen. 6.022x10^23 particles and its always that number and the weight changes because some things are bigger particles than others. That's the way it was explained in the text book and it's one of the main things i learned in chem.

[@peasedustin]

steve is always showing something interesting!

[@kingshukcs]

Really good video...took me a while to understand....but I did and it felt good thank you!!

[@ScienceSketch]

Hi Steve, thanks for the vid. Since 1993, the proper unit is the Dalton, not Atomic Mass Unit. The Dalton (Da) is the accepted SI unit for atomic weight. The Dalton is named after the legendary English chemist and early proponent of atomic theory John Dalton (1766 - 1844).

[@ThomasTheThermonuclearBomb]

*laughs in American* *cries in American*

[@Halestem]

Me chilling with my Carbon units 💀

[@heyk-lee]

Ah Avogadro! My Junior year of high school chemistry class used to make a HUGE meme of his name. We would call him "Avocado", and we even got the teacher to call him by the name! Ah good times that really helped me remember moles!

[@gnorts_mr_alien]

I didn't know you took acting classes Steve. What a versatile person you are.

[@khadijakhan1941]

Wow that clarified my concepts, thanks 👍🏻

[@ichigo_nyanko]

I had no idea people found the concept difficult. My first chemistry teacher likened moles with a dozen (except with a lot more things) and I understood instantly

[@jasonreed7522]

Same, its used exactly like a dozen or any other weird name for a number like baker's dozen being 13, or score = 20. Its just the value is strategically chosen and crazy big because atoms are so small. (The strategic value just making it so you can do your ratios as mols of stuff and then measure out until the number for the atomic mass shows up as grams on your scale.) In school our joke was its a chemist's dozen, because that really all it is.

[@parsphere6357]

Thats how im learning it too

[@Lampe2020]

5:16 You got me! I had to laugh :D

[@rafbambam]

Wow I've never looked at it that way, nice way to see it. You could say that a Mol is somewhat like a dozen, where a dozen is 12 of something and a Mol is that big number of something. Nice to see it explained like that. Greetings from Belgium.

[@shaugi]

At high school, moles were the thing that really stumped me during chemistry. I stayed late many evenings with the chemistry teacher to try adn figure it out and just could not get my head around it. Moles= Mass/RAM is still stuck in my head 22 years later. Possibly why I preferred biology.

[@tristannavarrete]

This particular subject of Moles has escaped me and prevented me from progressing my understanding of chemistry. Thank you Steve! The relative ratios of Mass needed for a chemical reaction can easily be over-explained.

[@s8w5]

8:19 I don't understand that animation (and find the explanation inaccurate). Multiple particles bound together are lighter than the sum of the masses of each individual particle. Thus the binding energy is negative. so to speak.

[@alazrabed]

Yes, this is a bit off.

[@davidhowe6905]

Yes, some say it should really be called 'unbinding energy', which would be positive; the energy you need to put in to separate the particles.

[@YourMJK]

That depends on the element IIRC. Lighter elements (H, He etc.) have negative binding energy (components are heavier than their sum) and heavier elements (U, Pu etc.) have positive binding energy. This is why getting energy from fusion only works with light elements and from fission only with heavy ones.

[@kuldeepsingh2983]

welcome to nuclear and particle physics.

[@kuldeepsingh2983]

in layman terms- amount of energy required to separate those atoms to infinity is binding energy. So binding energy is negative because we define it in this way. And negative binding energy means it will release some energy when 2 atoms are fused.

[@swastithakur4363]

Indeed a good explanation sir, you are a great teacher sir 🙏🏼

[@deadlyembrace8326]

Brilliant explanation! I think I finally get what a mole is!

[@timhyatt9185]

the best explanation i've ever heard about how to imagine a mole, is to imagine it as a stadium, with that many specific seats. doesn't matter how big the atom is.. it still gets one seat each..... Still can't do stochiometry though; i'm hoping I can borrow a philospher stone from somewhere, cuz that's the only way my equation will ever balance..

[@willridgway2513]

Thank you, I'm a highschool student going into Engineering and chemistry is the bane of my existence

[@joshuawilson7464]

Suffer

[@yashthakre8106]

I feel you

[@Peter_1986]

I studied a chemistry course in university a couple years ago, which largely was a slightly more formal version of high-school chemistry, although it did talk at great length about hybridizations and valence bond theory, which was a bit annoying.

[@ZombiesSlaier]

Chemical engineering gang rise up

[@willridgway2513]

@@Peter_1986 where did you study?

[@MorrisDrummond]

Gawd I wish this was around when I was doing Chemistry back in 1987. Moles were forever a mystery to me, which had a knock on effect on my understanding of the entire subject

[@smellycat249]

Just got recommended this video for the first time. So glad I got the 🔔 set to all so I don’t miss great videos like this 🤨

[@vishesh0512]

With the 2019 redefinition of SI units, the notion of units has changed in that we have fixed the universal constants like speed of light, planck's constant. So, now mole is not defined in terms of the number of C-12 in 12g. It is defined as the exact value that WE picked for Avogadro's constant. en.wikipedia.org/wiki/2019_redefinition_of_the_SI_base_units#Mole For all units, we now derive the measure of the unit from these (somewhat arbitrarily, cleverly, fixed) constants. Eg: The metre and second are as long as they need to be so that the speed of light comes out to be that constant. I think this was a huge change in perspective when we first did that: understanding that we are the ones defining the unit. And we can and should mould our definitions to suit our equations and precision needs.

[@Nartinan]

Haha... mould. Also, since you know a bit about SI-units, do you know why a mole is part of the SI gang? Every other constant has some secondary units deriving from them. Like velocity (m, s), force (kg, m, s), lux (cd, m). Nothing derives from a mole. It's just a number.

[@rhoddryice5412]

You say we can and should, but I think we should let Steve Mould it.

[@vishesh0512]

​@@Nartinan You caught my pun haha :D To answer your question, a mole measures how much (many?) of a substance you are talking about. It is dimensionless. But it is a _measure_ of something (and thus part of the SI). It is not just a number in the sense that you can't (shouldn't?) say things like "1 mole kilos" to mean 6.022 x 10^23 kg. A mole is not just a number with a name. You can not use 'mole' outside the context of measuring something. Edit: Added a summary line.

[@JohnDlugosz]

@@Nartinan Why: because long before we could resolve individual atoms and weigh them with any precision, it was necessary to come up with a standard. It was something people used and got taken up in the same overall effort that gave us SI. Before SI, there were still standards and agreements to be kept, but it wasn't just "a number". It's the way of determining the values and keeping the list, based on all the reaction ratios of many reactions. Just start with H=1. But it turned out to be easier to start with O=16. See: need standards! As technology improved, it became possible to simply weigh atoms and molecules and, "hey, it's just a number guys." but you still need to agree on the conversion factor between atomic mass units and grams. They are defining grams... so defining a Mole as a number ends up defining what an atomic mass unit is. Oh, and forget O=16, the new state of the art measurements is to start with C=12. But not just any sample of C, but now we knew about Isotopes so it's C-12 is exactly 12. Anyway, the importance of having a standard and the complexity of what's actually being done was once far greater than simply saying "it's just a number".

[@vishesh0512]

​@@JohnDlugosz I don't agree with your reasoning that mole is an SI unit because it defines the ratio between a gram and an amu. That is just like saying that 2.54 should be in SI because it is inch:cm. A thing gets in the SI because it _measures_ something - it is, after all, the system of units of *measurement*. A mole _measures_ amount of substance, a measurement that happens to be dimensionless.

[@IanWilkinson]

Casting my mind back 55 years, moles contributed to my giving up on A-level Chemistry and a career in medicine.

[@dee2273]

I usually tell my students it's a value we made up to quantify atoms, but I will be adding some of what you said to better flesh that point out. Thanks for the insight

[@TunnicliffeEducation]

Useful video thank you keep up the good work :)