The Mole and Avogadro's Number

[missnataliajade]

arghhh please make another video. i really don't get it. I mean I get the mass of a mole.. but I don't get the atoms part of it. Isn't a mole the same as an atom then? How do you work out how many atoms in a formula from moles and masses??

[Sophistiqiue]

Thanks it is really helping got my science exam the day after tomorrow

[hellocutie56]

I'M SAVED!

[fuckinggingerass]

my professor went over this so freaking fast! i ddnt understand anything in the lecture

[Rind0Man]

You deserve a noble prize.

[crysty200718]

Thank you very much man!

[sumdirtymexicanguy]

You sound a little bit like Optic Hecz if you know who he is..

[100ammarrizvi]

lol in this tut why are u talking about hairy apples? please stay on topic

[LuckyxTurtle]

McKeachie???? i wonder if my chem teacher saw this, because he used this almost exact lecture!!!

[karlathesecond]

I luv you

I get it!!!!!!

I won't die now :D

[BloodHarvest21]

The idea was confusing at first, but it gets very easy once you go along

[menthol5]

I once calculated the volume of a mole of ping-pong balls. I assumed a diameter of 4 cms (I think) and got a cube of ping-pong balls whose side would stretch from Santa Cruz to Chicago. A s*** load. The sheer size of that number is staggering. Atoms are incredibly tiny.

[ChippyChibnutz]

I think i need to smoke more herb...ok I got it now!!!! :D yay!!

[Charlaaay7]

This thing, as cheesy as it sounds and nerdy, is actually super helpful to me. My class is hella noisy, and I need to pass my Chem test tomorrow, so thankyou!!!

[PompousFlea]

Khan Academy has revolutionized my education.

[the0nutcracker]

awesome you saved my life ;)

can you pls specify the topics in class 12 chem pradeep fundamentals

thnx

[Russia2point0]

Thank you so much for making this video! It really helped me understand and you explained it so well! I finally understand! And just in time for my exam, you really saved me!

[Belldandy722]

Thank you so much! I wish you were my Chemistry teacher :I

[rozenczveig]

Yeeeeee THank you somuch for this i have my exam on Friday ! ty so much

[annagilda1]

You have laterally changed my life! I've been studying Chem since September and have only had these things click in the last couple of hours! I might actually accrue a few marks in my exam on Friday!!!!

[theONLYiCEE]

Very huge number? Very big number...

[TPBHvideos]

its avogARDO not avogADRO

[mylaughter13]

@TPBHvideos

Umm... No it's not? It's Avogadro. Check your Chem book, google, anything.

[TPBHvideos]

@mylaughter13 oh yeah your right... my teacher pronounces it avogardo... ill tell her about that

[milkncookies32]

I FINALLY UNDERSTAND

YESSS

[xxvolcomxx56]

most simple *



[456lawrenz]

i'm gonna use this excuse to use the computer while studying so i can 9gag

[foxywizrad]

Im screwed i got my Exam in less than 6 hours

[charsgirly]

oh yay. :D

no prob at my chem test tomorrow.

[vuvuzelaattack]

Now i can actually have chance of passing my chemistry exam. Oh and i have the worst chemistry teacher, the final exam is tomorrow and we haven't learnt stoichiometry, atomic structure, and periodicity. never trust a teacher with the name festus

[SYRINA112]

This is Fuckiing easy

i never had a problem in solving this shit :P

[abrahamgreenidge]

your the best men, thums up am always looking forward to seeing your videos on you tube regarding chem.

[MediumNothinFull]

wait a sec mole might mean earth because ya know..

[MediumNothinFull]

in 12 grams of carbon you have a ton of atoms

in 12 grams of carbon you have 12 grams of atoms

[shadowdude2009]

its 6.022*10 23

[PcJaiden828]

i was about to comment on how you took the atomic number instead of the atomic mass and it confused me soo much, but then I watched a little further and you realized your mistake and took the atomic mass afterwards instead. YOU SAVED ME so much confusion

[SaleishaC]

this helps a lot! thanks!!

[chtadow13]

Chem exam tomorrow on this lol

[indiajag1]

This was really helpful. Thanks!

[ichbinich1012]

Got a chem final tomorrow and I'm pretty sure I'm failing the class...I wish I found out about this channel a little earlier.

[TheOmzy]

aluminum lol

[vimdhana1997]

idotic chem exam also the avogadro

[marlena362438]

I found this video lecture very, very helpful, and I agree the definition in the wede... I can;t spell it, is confusing, but your clarification of everything was oh so good. You're a great teacher sir and keep up the great work.

[acweezer]

ehhh chemistry mid terms tomorrow... ging to be up until 3 learning things i should have learned a long time ago

[Karlyhh9]

21 people have moles on their left thigh.

[kliqit]

my science final was today, and i just found out about this. damn

[patkap41]

You are the reason why i Understand everything ranging from bio to chemistry to math. You are the best online video tutor source period. Unfortunately, I still can't grasp the true idea behind the mole in this video. I would strongly encourage you to make another video on the mole and avogadros constant because it is soo Vital to the idea of chemistry.

Sincerely, Pat, Plus hundreds of thousands of others who are too lazy to log into their accounts on Youtube and comment on the videos.

[swanny9990]

im so fucked for my chem exam tomorrow...

[bassbass99able]

@swanny9990 hahahhahaha me too

[80sfanforthewin]

@swanny9990 I got a final tomorrow :(

[WTFskillsproductions]

@swanny9990 highfive, we're all fucked

[TheHatlessllama]

@swanny9990 Same here bro. Same here.

[christianblake8]

i nneed more hellp

[ArunVevo]

@christianblake8 u will fail : D

[Xroswarsfan]

Thank you so much for putting these videos up. I have a hard time with chemistry and these vids help a bunch.

[Jamaicanbeay]

:) sal u rock!!

[warlockzombie]

Atom apple

Ba-Dum-Tssh

[ocmentos]

I never quite understood something, If anybody please explain to me, why does 1 gram equal to a mole of any number? for example if amu is one, times it by a mole it equalls one gram, if it is 32 times it by a mole, it is still one gram, why?>????

[s10dlka]

@ocmentos because 1g of any substance contains 6.02x10^23 (or 1 mole) of amu

12g of Carbon-12 contain 6.02x10^23 atoms. Each atom contains 12 amu. So:

12g of Carbon-12 contain (6.02x10^23) x12 atomic mass units

16g of Oxygen-16 contain (6.02x10^23) x16 atomic mass units

32g of Germanium-32 contain (6.02x10^23) x32 atomic mass units

In all of the above, 1g of anything contains 6.02x10^23 amu

OR 1g of anything contains 1 mole of atomic mass units

Hope that was clear!

[ocmentos]

@s10dlka I got it! so X amu times mole equals X gram.... that simple, thanks a lot!

[maketake]

n=m/M

[nukerecon]

so...what if ur solving how much moles there are in an element. Say... how many moles are there in iron?

[zverevavika]

I love these videos. <3 <3 thank you sir!

[EmzyBooWemzy]

But why do we need moles in life?!

[Bluelemonzz]

@EmzyBooWemzy it's used in chemistry.. using moles is an easier way to grasp the weight and size of aroms

[EmzyBooWemzy]

@Bluelemonzz I know it's used in chemistry. I just thought it made things complicated :\

[jacobheifetzlicht]

@EmzyBooWemzy We don't. I hate chemistry with a burning passion. Teacher goes too fast, and has extremely hard tests. I miss biology with Khan help. That was fun.

[SuperBlackpitbull]

is there another video available i 'm HS and I just cant get some of this stuff in my head

[Dectheboner]

Well Moley christ

[Reason4Existence]

I swear this guy can teach more than my 30 year experienced doctorate chemistry teacher.

[michaeljacksonator]

you really messed me up at the beginning when you said 1 gram = 1 mole of Carbon-12...

[BigOto2]

ROFLMAO @ 6:05. I know why you didn't want the "s" there on an educational video that we have to watch for HW.

[scarlito1]

i amin debt with you mister. thank you/!



[chantelleo100]

Wow, i missed the mole chemistry lecture at uni and was forever lost, now it all makes sense!!

[DiaryOfAWallflower]

@chantelleo100 same here! it makes sense now :)

[TheAlbanianator]

I have a mole on my ass

[Dectheboner]

@TheAlbanianator hahahahhaha

[Zatro61107]

Dude this is the 2nd video I watched of yours and it really helped me a lot! Is it sad I learn more from your youtube videos then I do from my professor whos been blabbling on and on about this for 2 months now?

[noblebishop96]

well that cleared stuff up thanks a mole

[roubydragdrop12341]

if you were my teacher, i would become a doctor in 3 years...

[AndyTheSmartGuy]

thank you very much i finally understand this mole thing!!! my chem teacher sucks ass!!

[goirkens]

Yes! I can understand this now! Hello "A" in Chemistry, hello University of Hawaii, and hello Japan!

[smitrib]

6.02 x 10^23 has some meaning now! and happy belated mole day everybody.

[GenericBlogger]

What? I actually understand moles? Thanks for the lessons

[LawinReborn]

Wait....Am I enjoying chemistry? HELL YEAH!

[briesibleyy]

Yup! My chemistry class is now my time for sleeping. Then when I get home.. YOUTUBE! it's not that i'm lazy, and extremely tired in that class(even though I am), its just the teacher's teaching method doesn't work well with me. So why waste my time pretending listening to her? ima just sleep :)

[littbballer24]

Thanks so much!

[JMan9391]

Avocado's Number = One GuacaMOLE!

Ba-Dum-Tsssh

[burning1er]

@JMan9391 ZING

[splendid99]

@JMan9391 loooooooooooooooooooooooooool

[puppylovr752]

@JMan9391 hahahahahhahahahaha

that's what my chem teacher told me!!!(:

[JMan9391]

@puppylovr752 Aww shwack, guess I can't claim it as my own. Thought I was only one to come up with it! :/

[0Dargor0]

You got to be a doctor in chemestry to understand those iupac s conventions .... I was one hour with my book trying to figure out what the hell this number is related to carbon ... now I see it´s only a convention ... thanks very much ...

[Yavan79]

Thank you! I am taking a virtual/online class and my course book really confused me, but you made it plain in less than ten minutes.

[ugasziz]

surprisingly, his voice gives me a boner

[charliebfmv]

Are there any more video's moving on from this stage ??? You make it so simple..teachers just confuse people lol

[gamerxdestiny]

so a mole is basically the element's mass number? correct?

[lizdadon]

@gamerxdestiny no to work out how many moles are in a element you do the mass/mr so e.g hydrogen mass could be 1g and mr is 1 so 1/1 equals 1 ...the mass number does not equal the mole it is only in that example.

[cutiesing3]

Hi!! I do sort of understand this, but I still get very very confused with the terminology....do you think you could make a video explaining moles and how they relate to grams, atoms, and amu?

Thanks so much again for this video...it did help!!

[italianpr753]

This guy teaches better than my Chemistry teacher!

[smokey13500]

your great. thanks alot

[doesnotcontain]

my school encourages us to watch your videos. if we dont get it from them. which we usually dont .

so THANK YOU !

[fatimalaraib1]

Videos of such sorts are a treat for self-studies.

This is an amazing piece of explanation supported by diagrams, tips and simple yet comprehensive advocating style.

just LOVED it

Thank you so much sir for that level of good explanation

[rikkigoodman1]

I love this guy!! I cannot believe I actually understand this now . Youtube is the preeminent tutor.

[curiousgeorge4442]

I hated learning moles b/c I didn't understand the calculations. Well, that was 10 years ago and if anything, my brain isn't as fresh. I picked this up in less than a minute. Unbelievable :)

[Shuffle2dMax]

continue ..... BUT this is IMP: even though they have different masses and different volumes too probably, THEY BOTH HAVE A MOLE wich means 6.02x 10^23 of 'things' each.

I'm by no means a professional and am learning like most of you, but I found this explanation helpful to help me understand this concept and wanted to share it. Correct me if I'm wrong.

[Shuffle2dMax]

Will try to explain better as I had difficulty with this ad watched other videos:

Let's say we have H2O, it's mass is 18 amu ( O -> 16amu + 2(H -> 1amu) = 18 amu ).

Basicaly knowing the mass we can tell how many grams are required to have one mole. The answer is 18 g to get a mole of H2O. What does this mean?

It means that 18grams of H20 HAS 6.02 x10^23 'things'.

If some other compound weighs say 38 amu, it would require 38 grams of that compound to get a mole. continue below............

[stanmusz]

Cheers mate! This video helped alot.

[adam10526]

im gonna bitch at my teacher to start showing this instead of him teaching us himself... Win/Win situation because all he has to so is show a video and grade, and we all learn a lot better, im not insane. im a visionary

[watercrystalfairy]

my AP chem teacher uses 6.022 instead of 6.02, so does my AP Book and the book i got to help study for the AP test

[iveinfrancisco]

how do i enroll in khan academy?

[Oliviababygirl91]

6:28 you almost confused the hell out of me..Glad you caught that thoo!

[joelgardner94]

err i don't get it

[shenzymaya]

can u pleeeeez explain why exactly this number, i.e. 6.02*10 raise to 23.....

why not any other number??

[blindfire4ever]

Thank you so much! I was having such a hard time understanding this!

[laduena0001]

I want you to know that when I have a question on anything from chemistry to microbiology, I come here to listen to you to teach me on the subject! maybe its my teachers that make it so hard to understand and now I know that 1 mole is the same as 1gram of what ever the wt is!! thank you

[Kevinguitar111]

17 people are assmole

[aboodal3las]

@Kevinguitar111 LMAOOOOO !! 

[VietnaMe3]

how can a mole equal 6.02214x10^23 then equal the atomic mass. Still makes no sense to me

[Presteros]

@VietnaMe3 The mole equals the atomic mass, in grams. 6.02214x10^23 however is the number of atoms in the mole. It's two different things. Kind of how like one cup of peas can both weigh 250 grams, and contain 200 peas. 1 cup = both 250g and 200 peas!

[Akire519]

I'm studying for the PCAT.....I think I can credit Sal when I pass!!!

[xxlarougexx]

i finally got wtf a mole means!!!!!!

[FrozenPeaches]

please replace my science teacher haha.

[madk777]

Best teacher period!

[Ezfiey]

hahahahha.. the best teacher in the Youtube! :D

[IbtiCool]

I have download almost all your vids from youtube. They helped me alot in my IGCSE exams and i just wanna say Thanks

[stayput212]

Thanks again!

[winniephy6]

ya. am really sry..i mean...1 mol of O (i.e 16 amu of O) weighs exactly 16 g,, so y cant Oxygen be used as a standard for measuring mole instead of Carbon (which has 12.01 amu)?.. It could make calculations lot easier.. isnt it?...

[000watchingyou000]

@winniephy6 C12 isotope is a stable isotope. so it is used as a standard medium for all.

your question which states the use of oxygen as a standard medium is good. But its mass = 15.9994 amu.

which is not 'exactly 16'.

[winniephy6]

Wow... am just following ur videos for the past few days, and these are really informative and give wondefrul explanations for the fundamental concepts.

I just have a doubt... the mass no of C-12 is around 12.01 amu. But from the periodic table, v can find that the mass no of O is 16. i.e, 1 mol of O (=12 amu of O) weighs exactly 16 g. So y cant Oxygen be used as a standard for measuring mol, instead of Carbon ? it just would make the calculations easier isnt it ?...

[kida746]

this dude is hella good @ writing w/ the paint app =O

[tjobtjobtjob]

@kida746 yeh men he ha ALOT of useful vids

[koagasa21]

thank you very much you saved me from being dropped from school ^_^

[ion010101]

12 grams of C have a mole of atoms. How do we know there are a mole of atoms in 12 grams of carbon? How did carbon get chosen? Saying, "1 mole corresponds to mass in grams" is what everyone says. That's easy enough to follow, but I still don't know what it's all about.

[jammy95100]

@ion010101 carbon got chosen 'cause it was the first element discovered and scientists just thought it easy to relate back to it.Eg. uhave 23g of sodium, you know the mass is 23g but you don't know the number of sodium atoms that are in that mass. Since 23 is the relative atomic mass of sodium on most periodic tables, it tells us that 6.02 x 10^23 number of sodium atoms in 23g of sodium. eg.u had 46g of sodium, u'd have 2 moles of sodium atom in that weight-> 2x(6.02x10^23). hope it helped?

[ion010101]

@jammy95100 First, SOMEONE REPLIED!!!! Many thanks. Ok. A mole is how many atoms are in 12 g of carbon (12). How did we know that in the first place? I guess I could google it only I wouldn't know where to begin (and on the innerwebs you have to wade through encyclopedias of junk before finding something useful). Eck, anyway, thanks.

[jammy95100]

@ion010101 lol no worries :) we know that about carbon coz since it was the first element discoevered, they ran a whole bunch of tests on figured it out. I guess understanding HOW the mole came about to be isn't really going to affect ur application of it in school or wateva. sorry, i cant explain it further coz i only just learnt it last term. but like the dude in the video said, just take it as a number. trust me, dont overthink it - itd drive u insane. just take it as a number :).

[ion010101]

@jammy95100 That part I follow just fine. Well, I'm making some headway in this, looking around. I'm trying to get my head around how it came about that one mole of an element is conveniently that elements amu weight. It's one of those things I'll kick myself over once I know, it's just on the other side of where my IQ ends.

[ion010101]

@ion010101 I mean, that, to me, is the important bit. Saying that it's a number, just like 12 is a dozen, is, to me, nothing. I could I not get that? But, what's important about it? So far as I can tell so far, it looks like a mole was simply defined to be the number of particles in 12 grams of carbon, and since everything is weighed relative to carbon, then 1 gram of H is one mole of H, and so on. Does that seem right?

[000watchingyou000]

@ion010101 I to have the same doubt.

[thewend59]

wow - i did chemistry A' level and as a subsidiary in my 1st year of uni, and I am not sure I really got this until today :D Training to be a science teacher, brushing up on my science. Maybe i should just sit back and play your videos to the kids heh heh certainly might set watching some for homework !

[RodaXnoir]

Thanks heaps man i missed a couple of school lessons and now I'm back on track

P.s your better than my chem Teacher at explaining things ^__^

[cocovite]

can u make a video on how to convert Moles to grams, Moles to atoms, Moles to mmoleclues and vice versa?

[SakoAgopian]

this guy is great! i love the videos

[T15Medic]

i literally watched like 5 of your videos, you just retaught me everything i need to know for the final, and it makes sense!!!! you are the best!

[serpentinexcubed]

So what I came out with is 1 gram = 602,000,000,000,000,000,000,00­0 Amus

[MyMPPM]

how do we sponsor some of your videos?

[Homkilla]

Isn't mole 6.023x10power 23?

[Kerosberous]

@Homkilla

Actually it's

6.02214179(30)×10^23

But do you really want to punch in all those digits in a test?

You can even use 6*10^23 in some tests, but when this isn't for school then it's fine to get technical.

[samanthabuhler]

This was WAY more helpful than my Chemistry teacher!

[JEFF12ALAS]

chem final in an hour !!

swad life

dank!

[MsRESPECT90]

@JEFF12ALAS

I hope you passed!!!!

[IBMua]

Ton of atoms in 1 gram. Sounds funny xD

[LouisJ277]

people are often confused by moles. the way i understood it was

the atomic or molecular mass of a substance is how many grams in 1 mole of that substances atoms. for example, 1 mole of sulfur atoms (6.02x10 23) equals its atomic number (32.1). so theroretically 6.023x10 23 sulfur atoms weighs 32.1 grams

[ahenry138]

@LouisJ277 That's right, except the atomic number for sulfur is 16 and the molecular mass is 32.1 amu (or 32.1 grams per mole). Atomic number is the number of protons in the atom.

[MrElmoussa]

i dont get moles. can you please make another video on moles

[Lovelastiing]

This is why i love youtube. Entertainment and helping me to ace chemistry. I LUV YOU HAHA

[RWSProductionz]

no



[BarbarianAss]

So can you say nucleons instead of atomaric mass units?

[DCskate714]

Hey Sal,

Why did avogadro decided to use 6.022*10^23 atoms instead of some other number like 100 or something?

[AgujaAzulMD]

Videos like this show just how horrible the education system is. Teachers can't teach this stuff to their class in an entire year and this guy does it in one video.