Introduction to pH, pOH, and pKw

[ATY8092]

i love you man

[rawdonwaller]

Pedantic though it may be, does H2O's subscript (l) stand for liquid? I thought that aqueous phase means that the molecule or ion is surrounded by water molecules, in which case water molecules themselves are 'in' liquid phase (because it doesn't make too much sense t think of water molecules solvating themselves)? Of course, this is a superb video, and I may be wrong anyway.

[Xiek11]

Is this really how simple this pH pOH thing is? My lecturer explained this in a really complicated way. Thanks a million. Great work!

[osama105]

but i do think it would help if you used LEGIT. examples instead of doing AB+CD ya knoww ohh and making them hard ones, ones you would most likely see on exams? LOl thankyouuu! bbtw. im tlking bout your le chatelier video.

[osama105]

you are soooo freaking amazing. like everything just makes sense to me now.

[TheYo12343]

"p" means potentz here

[rawdonwaller]

@TheYo12343 Maybe 'puissance', as in puissance de Hydrogen? 'Puissance' is the French term for 'power.'

[scs6089]

I love you.

[Iamnobodynobodyisme]

is there anybody out there like Sal-Man? Ye, I didn't think so.

[NomsNomsNomsNoms]

great :) didn't notice any mention of pKa? thanks you :)

[x0xbethaNyyx0x]

you're amazing.

[thiagosalazar1]

Khan changed the way we see Education, and thankfully to him, I passed in my exams to become a Professor from University. Thank you Professor Khan!

[chrisndjames]

i can't wait to do A level chemistry.

[Alfietto92]

Flawless explanation =D

[mmcakes100]

You the salMAN!

[adivakaruni]

i wish i had found these vids while i was taking gen chem! so helpful and clear!

[azndude3600]

Why would water form hydronium? I don't understand it. Oxygen is already happy with its 8 electrons. Why would it get another proton?

[christyc463]

@azndude3600 i don't know for sure, but since no one else has answered you... i think it's just something that happens from time to time randomly. atoms and their components are always moving (electrons, in particular) and occasionally, they move in ways that are very unusual, but not impossible..

[azndude3600]

@christyc463 I think I found out. I think its a form of intermolecular forces and in this case its ion-dipole attraction.

[Jfrancis221]

We should use (l) for H2O indicating it is a pure liquid, not (aq)

[milanaa]

Thank u soo much!!!u really helped me with this video.

[The19thKey]

@khanacademy you said at 10:00 that M = mol/l. but isn't M = g/mol??

[BackCountrySR]

@The19thKey M represents Molarity, and the molarity is found by Moles/Liters of solvent, in this case water.

[mvadim25]

@The19thKey Molarity is mole/liter

[necaccamo]

@The19thKey g/liter= density to get the molarity(M) you need to convert grams to moles. Molarity= mol/volume

Volume= liters or millimoles/milliliters. =)

[necaccamo]

@The19thKey g/liter= density to get the molarity(M) you need to convert grams to moles. Molarity= mol/volume

Volume= liters or millimoles/milliliters. =)

[The19thKey]

@necaccamo thx :)

[The19thKey]

"of course water is desolved in water" :D

Anyway, you're my science-hero

[mgold5284]

you are my hero

[007abhinavagarwal]

amazing.

[paulceltics]

very helpful. this is something that is going to save my grade

[surfer3595]

8:11

little stutter haha

[risquewebsite]

i seriously had an epiphany while watching this

[pepteamsergi09]

How do you get those concentrations? or where do those concentratons come from? what's the math behind it? thank you.. still the Video is 4.5 stars

[NandD1337]

@pepteamsergi09 howd the hell is the vid 4.5 stars? its 134 like 2 dislikes so 5 134x5+2x1=672 stars/136 dislikes making the vid 4.94 stars

[Janac]

@WarpFieldTheorist haha but rusty is completely right. khan made an innocent mistake, you cannot have aqueous water (which suggests water is dissolved in water). Thanks for point it out rusty, i don't feel that your comments are "bashing with education".

[alriisehansen]

@Janac It not mistake, you can talk about water concentration in water. Its 55.5 M which is very high, for this level of chemistry the concentration is usually set to 1 dimensionless, since water is the the main component in the reaction.

[lmccreazy]

Thank you sooo much!!! You are extremely helpful with all of my subjects and I really appreciate all of your videos!

[baburo101]

Why lower case and Upper case? pH, pOH, pKw?

[xshoreLS1]

I think I could have read this in 20seconds tops.

[computorcompaq]

THANK YOU! SO MUCH! I study in french but this is still very helpful!

[AbhiLabi]

OMG i wish i found you last week, now i have a test in like 3 days and im just learning everything from you rite now :)

[cherryboyv]

i wished i found khan-academy years ago. cause i really want to watch ALL of your videos.

they all make me go "ka-me-ha-me-ha" lol

[QueenRiddler]

@cherryboyv LMAO.

[1xtra299]

@WarpFieldTheorist & @northlight72: do you guys have any links that prove what youre saying? im all confused now... even my professor says that H20 should be a liquid

[boardies1337]

water is a liquid(l) 

[Rusty2891]

@WarpFieldTheorist Your a PhD student (guessing Chemistry) and you think

2H2O(l) ---> H3O+(aq) + OH-(aq) is wrong? I actually went out of my way to visit my Acids and Base lecturer to ask about this and he said that H2O is a liquid. What did I say that was critising the video? I pointed out 1 error and thats it.

And calling me a Troll...well the less said about that the better.

[northlight72]

Whoever you are, someday I want to meet you and shake your hand.  There's nothing you can't put in understandable terms.

[Rusty2891]

@WarpFieldTheorist Water is not aqueous. When the word water is used in Chemistry it means H2O. There are no salts, no dissolved compounds or a 'swamp' of materials in this. If there was, it wouldn't be water in its purest form, and this purest form is what is being referred to here. And by the way, I am at University working my way through a masters degree and never before have I seen H2O (aq).

[northlight72]

@Rusty2891 Seriously, shut up. This is helpful. This guy got me through Calculus and now Chem II because he has a way of explaining things so you get the greater picture. Your masters degree seems to only be working to give you an unwarranted sense of superiority. Do everyone a favor, NEVER teach, and STOP "helping".

[Rusty2891]

@northlight72 Have you actually ever ready anything I put? I simply pointed out one mistake, and one other way of saying something. Your saying I am not helpful when people have said that I have been. I mentioned my masters degree as someone said that 'il understand better at uni', so i mentioned that i was already at uni and havent heard water as aqueous. I've never attacked the Khan Academy, even when he made a mistake. His videos are fantastic and helpful. And thanks for the career info :)

[northlight72]

@Rusty2891 Honestly, if you are so concerned with being helpful, make your own video. But again, stop.

[Rusty2891]

@northlight72 But again stop? I'm confused.

I'm not making you or anyone take my help. Don't read it if you have such an issue with it. It's ironic that your having ago at someone for helping, on a video that has the primary aim of helping. So go enjoy dropping marks in chemistry exams (which you will do for putting the incorrect state symbol for water at stp).

[Rusty2891]

@WarpFieldTheorist I received an email saying and I quote " And yet the protons and hydroxide ions are certainly part of an aqueous solution, in much the same way as sodium and chlorine ions can be part of an aqueous solution. When you study chemistry at university you discover that there are all kinds of weird structures floating around which are made of many 'water' units and ions. It is perfectly acceptable to refer to this swamp as an aqueous solution."

[alvaro2416]

Thank you very much!! i was soo confused. Now i understand how this work! yay!!

[brixperience]

does this mean that whenever there's a decomposition reaction, the reactant doesn't get plugged into the equation?

[salehjoon]

some dimwit actually disliked this video?

[brixperience]

@salehjoon lol... it must have been a mistake

[scarlettbildhauer]

This video was really helpful. You should have a comment section on your website so that students can give you feedback. Thank you!

[QuantumCoulomb]

awesome! i love chemistry!

[Rusty2891]

H3O is known as a hydroxonium ion aswell. Also H2O is not aqueous, it is a liquid. You can't dissolve water in water.

[furyofnasa]

@Rusty2891 I agree

[crashingreality]

@Rusty2891

ok i am relieved

that confused the fuck out of me

[yusufforever]

i drink hydronium

[smit240]

helpful in exam thanks.....lets related to biology

[smit240]

helpful in exam thanks.....lets related to biology

[LordAlda]

H2O (l) not (aq), because pure liquids have the probability of just being there.

[Poochester]

you are amazing.

[MrOhyesbaby]

keep posting your clip brother! speechless...it's an easy and clear way to reach an understanding! two thumbs up for you!!!

[Subaangen]

of course you are Indian...cleverest people in world...:)

[HowAboutSomeTruth1]

@Subaangen

Yet still poor, extremely racist and sexist.

[theartyard]

Thank you so much! Your explanations are so clear and easy to understand. You make super chemistry fun! :D

[saundie1000]

great teacher thank you very much

[jwardmagic07]

Sorry, thats was insanely hard to understand :(

[arswati]

This actually makes chemistry easy!!...gud work

[crashonthehumble]

nice work