pH and pOH: Crash Course Chemistry #30

Рет қаралды 2,135,736

11 жыл бұрын

In this episode, Hank goes over Reversible Reactions, the water dissociation constant, what pH and pOH actually mean, Acids, Bases, and Neutral Substances as well as the not-so-terrifying Logarithms, strong acids, weak acids, and how to calculate pH and pOH. Oh, and litmus paper!
Pssst... we made flashcards to help you review the content in this episode! Find them on the free Crash Course App!
Download it here for Apple Devices: apple.co/3d4eyZo
Download it here for Android Devices: bit.ly/2SrDulJ
--
Table of Contents
Reversible Reactions 3:40
Water Dissociation Constant 5:00
Acids, Bases, & Neutral Substances 6:38
Strong and Weak Acids 7:43
Logarithms 1:46
Calculating pH and pOH 8:45
Cool Mathematical Connections 9:54
Crash Course is on Patreon! You can support us directly by signing up at / crashcourse
Want to find Crash Course elsewhere on the internet?
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Пікірлер: 1 100

@crashcourse 4 жыл бұрын

Pssst... we made flashcards to help you review the content in this episode! Find them on the free Crash Course App! Download it here for Apple Devices: apple.co/3d4eyZo Download it here for Android Devices: bit.ly/2SrDulJ

@sujaybelsare4743 4 жыл бұрын

YAY

@aldrindeleon8910 4 жыл бұрын

Yay

@anchitrao7374 8 жыл бұрын

These videos are ridiculously well made

@krishnagoli687 5 жыл бұрын

Damn they'd be really helpful if they went just a bit more into detail but nonetheless amazing production quality

@Spycyzygy 8 жыл бұрын

My chemistry teacher described the water to hydronium and hydroxide as water being so bored that it reacts with itself

@waltermitchel6266 8 жыл бұрын

lol

@hassankhansa8603 8 жыл бұрын

+aung Oo ROFLLMAO

@HonzukiNoGekokujou 7 жыл бұрын

Rsaramallac Mine too!

@lanhua216 6 жыл бұрын

Rsaramallac e

@RyanBucao 6 жыл бұрын

@foxyred3216 9 жыл бұрын

"p" is an old mathematical symbol for "-log of" hence: pH = -log[H^+] pOH = neglog[OH^-] pKa = -log[Ka] pKb = -log[Kb] Well, that's what my chemistry professor, Dr, J. Rogers, told me.

@kristina1463 5 жыл бұрын

THANK YOU

@rhythmthukral7857 5 жыл бұрын

Shut up

@ScareSans 4 жыл бұрын

@Rythm Thukral you misspelled "you're welcome" Edit: Jesus I'm an idiot, I meant you misspelled thank you

@pollenbunal2101 4 жыл бұрын

Arceus The God Pokemon Hahahahahhahahah

@aigle_grincheux 4 жыл бұрын

Francis Martinez definitely the most helpful thing I ever read Especially when I try to learn something about pH for the first time in my life thank you 💜💜

@pilotmoyafan 10 жыл бұрын

I'm still kinda screwed for the test tomorrow....

@1nfo663 5 жыл бұрын

did u pass

@Tutti22 5 жыл бұрын

Nameless lol

@shaisblind 5 жыл бұрын

lol, some guy replies 5 years ago, someone replies 5 days ago..😆

@pcrd38 4 жыл бұрын

Howd ya do man?

@ctsvblk 4 жыл бұрын

ShadowBIRD maybe he died.. like actually

@nickracca1993 5 жыл бұрын

"ok so now that you're terrified, I'm here to help" -hope someone told me that word earlier.

@daiwikdhar6464 4 жыл бұрын

For a second while he was explaining logs, I realized Hank has great potential to start: CRASH COURSE MATHEMATICS!!!! Anyone who wants Hank to explain Math plz hit a like!!!

@jessjms1181 8 жыл бұрын

Why is water so cute

@jessjms1181 7 жыл бұрын

Dan Vegas I don't remember why I said it to be honest

@braveheart3847 7 жыл бұрын

lol

@dmoneyswagg64 7 жыл бұрын

Dan Vegas why did I like this comment?

6 жыл бұрын

because it obeys you, molds to your every desire, because it's the girlfriend you'll never have because all you care about is yourself

@chemistrychannel5021 5 жыл бұрын

Because it's bent 😂

@drew.k2385 7 жыл бұрын

"As you can see, the logs turn out to be a mathematical shorthand that saves us from having to deal with very huge or very tiny numbers." That makes so much sense now. Why can't textbooks just tell it like it is?

@IndeedJoe 10 жыл бұрын

finals anyone?

@Togerax 10 жыл бұрын

You know it :D

@RedMinorFilms 10 жыл бұрын

Sadly my finals are way above the the stuff in this video

@thatnonamedude 10 жыл бұрын

hi Unfortunately, me too

@felixwiedenmann8625 10 жыл бұрын

Yep it got me too

@Gravios74 10 жыл бұрын

Pff, yes

@fluffy3355 4 жыл бұрын

god i hate how chemistry has so much vocabulary

@MasterGus501 10 жыл бұрын

Man, you're great at chemistry! Have you ever considered cooking crystal meth?

@dreadxo4083 6 жыл бұрын

Hankenburgh.

@zombieblood1675 6 жыл бұрын

Gus F breaking bad refrence. lol.

@varshitakolipaka7933 5 жыл бұрын

BREAKING BAD.

@Telishahful 5 жыл бұрын

most heard sentence of a chemist

@happymolecule8894 5 жыл бұрын

Cooking cocaine is much better

@windowsxboxguy 8 жыл бұрын

this the type of guy to help me pass my test tomorrow

@MagicallyEmily 10 жыл бұрын

I honestly understand chemistry better through these videos than I do through my actual college chemistry course. Thanks, Hank!

@Valdagast 6 жыл бұрын

And the pH of blood should be between 7.35 and 7.45, _not_ (as I read on an alternative medicine site) 5 and 9.

@khalidjaved5325 4 жыл бұрын

It is 7.4 written in my book

@josiahklein70 8 жыл бұрын

Crash Course Mathematics, anyone?

@basmetten7164 7 жыл бұрын

@consavvy5754 7 жыл бұрын

Yea

@aperson3859 7 жыл бұрын

Josiah Klein yes please

@mystuffnthings23 7 жыл бұрын

Yes, Please! He makes everything way more fun.

@firozbakhtahmed4428 7 жыл бұрын

Josiah Klein Yeees

@storyspren 9 жыл бұрын

That pH + pOH = 14 is actually really cool, since it's a nice little shortcut you can take when you want to know either of them and know the other.

@SWEm4rt1n 11 жыл бұрын

I love how this series is perfectly synced with my lessons in college so I can repeat my studies while I'm on youtube :D

@riyasingh7287 8 жыл бұрын

Can we have CrashCourse Physics? :/

@kimberlyyeokahyii 8 жыл бұрын

They alrdy have it but it's not Hank doing it

@LA-rp5uy 7 жыл бұрын

Riya Singh have you even searched it?

@kripashankarshukla4073 6 жыл бұрын

It is there, search it

@fernandobaranano5032 6 жыл бұрын

I come from the future, they've already done it, enjoy!

@sumantrajkumar7372 5 жыл бұрын

careful what you wish for

@Sophie-wf3ex 7 жыл бұрын

"...in the example we just did the pH was 5.4 and the pOH was 8.6" (10:02) erm... Wasn't it 3.5 and 10.5... Interesting editing.

@jungsooneul8879 7 жыл бұрын

I thought so too...

@miav2046 6 жыл бұрын

i caught that too and threw me off. kept rewinding thinking I missed something, at least our answers 3.5+10.5=14

@arianasanchez4746 6 жыл бұрын

Damn. I'll look for another video to study 😭😭

@ScholaBayBee 6 жыл бұрын

sameee

@plazmavolt1238 6 жыл бұрын

yeah...

@BJB104 Жыл бұрын

Man, these vids helped me big time when taking chemistry in college nearly a decade ago. I work as a chemical technician in the semiconductor field nowadays, but rarely use theory and forgot quite a bit! Now watching again to give myself a little refresher for teaching my nephew with his high school classes. This is rad! Forgot how much I really liked this stuff..

@krisxcross 10 жыл бұрын

This helped me so much for my AP Chem class! We have to do a reading on this over the weekend and I didn't understand anything until I watched this video and also the acid-base reactions video! :D

@Abominatrix650 8 жыл бұрын

I'd just like to say that during the Kanye bit at the beginning, there's a Damocles Sword above his head. Thought we wouldn't notice. But we did.

@JoshuaLoganjoshuadlogan 10 жыл бұрын

This is a great video series. Thank you for taking the time to make this!

@f0gman_ 11 жыл бұрын

Thank you so much Hank! This crash course actually helps me a lot in school.

@2357y1113 11 жыл бұрын

Crash Course, thank you so much for believing in your audience and therefor not being afraid to show actual math(s) and formulas. You're the best!

@JuiceCarver 10 жыл бұрын

Thanks Hank! My teacher has been repeating the same material to us for 2 hours and nobody got it. Praise Hank for 10 minute crash courses!!

@nmubunny5395 10 жыл бұрын

Your videos are really helping me with my MCAT, thank you so much!!!

@stevenn2382 6 жыл бұрын

Thank you so much! We went over this in chem and I thought I knew it well but this explanation helped me much more!

@PerryTheGangsta 8 жыл бұрын

10:05. Was that a mistake on his part? The numbers he got from [H^+][OH^-] were 3.5 and 10.5 in the example he used. Thankfully it still equals 10^-14 in the end, though.

@bvbandiss 9 жыл бұрын

These videos have helped me so much in my chemistry class. Thank you 😊😊😊

@DoctorSkater 11 жыл бұрын

I already know every subject you have gone over in crash course chemistry. And yet I am nonetheless entertained by each and every one. You rock Hank :).

@manimaima 10 жыл бұрын

These videos are really helpful. You see I’m in year 10 and i really like chemistry. I’ve even started to learn AS chemistry. These vids make chemistry even more fun!

@neutralpresident4361 9 жыл бұрын

My pH would be 7 because I'm neutral.

@FROPDESAI 9 жыл бұрын

Neutral President Neutral President is neutral.

@darraghbrennan8549 7 жыл бұрын

Neutral President ii

@mihajlojovanovic7651 6 жыл бұрын

Mine would be 14 cause I'm basic

@tobey1684 5 жыл бұрын

@@mihajlojovanovic7651 lol

@mollyhorse 5 жыл бұрын

@@mihajlojovanovic7651 and caustic! Lol

@hazzacookiemofo 9 жыл бұрын

I love all of the pop culture references in the show, like Deadmau5 when Hank was talking about Strong Bases

@mollyhorse 5 жыл бұрын

Love these videos! Love love love! Makes me laugh while I am learning...thanks!

@captainsmurk 10 жыл бұрын

I'm such a huge fan of this guy and these videos! Awesome.

@ScarecrowWoods 10 жыл бұрын

i have no idea what im watching i think my brain is melting

@andjeladzambas2874 4 жыл бұрын

know how you felt....uffff

@jbkjbk1999 9 жыл бұрын

English speakers trying to pronounce Ø, Æ and Å never gets old.

@MrInsdor 9 жыл бұрын

He does it pretty well though, ä ö and ü mostly get "ignored" and will be pronounced as a o and u : ^)

@eliotoboyce5738 8 жыл бұрын

+MankeyFrankie GöØd fØr ü

@landonhillyard 8 жыл бұрын

+Totally Not A Cylon Lived in Norway for 2 years. It took a bit for people to think I was from Norway, but eventually I got it.

@IhaveCupcakes 8 жыл бұрын

+Totally Not A Cylon I must agree

@rithwiqnair537 8 жыл бұрын

Helped me a lot.... Doing great Hank Green!

@MD-nf5rr 4 жыл бұрын

you're good at this man, keep it up!

@allenhoggan7675 5 жыл бұрын

Deadmau5 was the last thing I was expecting to see in Crash Course XD

@PartyChicken407 11 жыл бұрын

Thank you guys so much for doing these videos. I'm not even a chemistry student, just a guy who was curious about world history (found the other crash course videos) and then I found these. Amazingly well put together and fun. I wish I knew what I know now back when I was taking high school science... I would have asked some really interesting questions and come up with some cool experiments.

@MegaMike327 6 жыл бұрын

Universities should uses CrashCourse as it was way more interactive then Khan.

@jeffshubert 11 жыл бұрын

Great job Hank! It would be interesting to learn about the dissolving powers of really strong acids.

@itskankan 11 жыл бұрын

That kanye power thing was the best thing I've seen on youtube this week! Keep up the creativity :)

@user-fc4ci6mg6h 7 жыл бұрын

You save lives man!...🙌🏻🙌🏻

@xXgracexX333 11 жыл бұрын

My chem teacher is awful...she should honestly just show these videos!!! They help me so much to understand! Thank's Hank!!!!

@Latnii 11 жыл бұрын

Thank you for this! I was in desperate need to understand pH and OH junk. Just in time as always, Hank!

@ScareSans 5 жыл бұрын

"all your base are belong to us" i don't even remember where that's from, but i see it everywhere. for example, my younger bro was watching rescue bots, a transformers show for small children, and a character actually said that... it's everywhere

@ggsyth1081 4 жыл бұрын

it was one of the first "memes"

@rex17ly62 4 жыл бұрын

A common misconception is that a pH of 7 means a solution is neutral. This is just wrong, what makes a solution neutral is whether [H3O+] = [OH-]. For example, Kc of water at a temperature of 25 degrees is 10^-14, in which case [H3O+] would be 10^-7 and the pH would be 7. But in a temperature of 50 degrees Kc increases to 5.476x10^-14, and [H3O+] would be ~6.63. However, since [H3O+] = [OH-], it doesn't matter it is neutral.

@world-suppliers 8 жыл бұрын

this help mr alot with understanding saponification , god bless you

@BlooregardQKazoo-ff6wb 11 жыл бұрын

This is exactly what I am going through in school right now! This has really help me thanks.

@TheMisleduser 6 жыл бұрын

can't lie. I should have been watching these instead of reading the text

@premgill2699 8 жыл бұрын

10:00 The video makes a error Hal says the PH of the example we just did is 5.4 + 8.6 = 14. This is wrong. Actually, the PH of the example is 3.5 + 10.5 = 14.

@veditababuta4201 8 жыл бұрын

That' what I thought too, I watched the that part over 4 times to make sure.

@babycash08 9 жыл бұрын

I literally almost had a mental break down in class yesterday. Today I find this goldmine! Life is really good LOL

@Syntaxxed Жыл бұрын

'so now that you're terrified" exactly my reaction when my teacher introduced pH and pOH without explaining us logarithms lol

@thelark2049 9 жыл бұрын

pH stands for: "potentia Hydrogenii" which is a newlatin word.

@rachelgordon8330 9 жыл бұрын

I was taught that pH came from French: pouvoir Hydrogene. Like, the ability to release the hydrogen ion and create hydronium ions...

@tiffanyxchoo 10 жыл бұрын

I'm so glad I came across your channel

@Dixavd 11 жыл бұрын

Yeah, I knew it would be something that would have to be true by definition. I was just impressed that there happened to be a model for giving the information of the H+ and OH- concentrations that aligned with using that fact so perfectly. I thought it was really neat that to represent this Chemistry information, they used this trick to make it so simple. Thanks for explaining though (I've always been bad at logarithms anyway).

@nicktimmerman8562 5 жыл бұрын

0.5 speed and I couldn't stop crying

@pri7974 8 жыл бұрын

Wish my chem teacher taught half as good as Hank teaches. Btw Please bring crash course physics soon :))

@nathanhe4214 4 жыл бұрын

Thank you so much, this is amazing

@JonathanDery 11 жыл бұрын

I just realised... I've been watching Crash Course since hte begining! Thanks for making me realise that, Hank!

@metadolle8925 8 жыл бұрын

I thought the "p" came from the mathematical p, which stands for -(log). My chem teacher likes to tell us that to find pH or pOH from [H] or [OH] we have to "p on the concentration" -_- I will never, ever be able to look at pH scales without hearing him crow, "What do you do? You p on it!"

@makeitmusical 8 жыл бұрын

+Josie Serpan Strangely, this helped me.

@metadolle8925 8 жыл бұрын

Sarah Hudak Awesome, glad to hear it XD

@h6ly 5 жыл бұрын

well tbh p stands for power and H stands for hydrogen, im no scientist but pH is the power of Hydrogen

@ScareSans 4 жыл бұрын

@Jordan_acidic Hank himself said we could not confirm if pH means power of Hydrogen.

@johndou423 6 жыл бұрын

Kw is only 1.0*10^-14 at 25 degrees celsius tho

@dustinpetersen8224 9 жыл бұрын

Loved the reference to All Your Base Are Belong to Us!

@jonmorris2232 10 жыл бұрын

Woah another channel with you...I NOW LOVE THIS CHANNEL

@linguaphilly 9 жыл бұрын

Haha that 'ohhhh'-moment at 6:28

@HarryBungholio 10 жыл бұрын

Just want to say thank you for helping me understand chemistry. I wish you were my teacher. Or that I could just watch KZfaq videos in my class rather than listen to a professor who cant explain anything. You rock. Thank you.

@MrMehawk 11 жыл бұрын

A great episode, Hank.

@jayantakumarborah 7 жыл бұрын

awesome... beautiful and interesting explanation..expecting more...

@shereitograce7844 8 жыл бұрын

You explain chemistry so well. I feel I have won a higher level of knowledge

@PinkLove961 10 жыл бұрын

pH and pOH stand for potency (p) of hyrdogen, (H) and potency (p) of hydroxide (OH), according to my chemistry teacher with a phD. (

@carolmcfarland9115 10 жыл бұрын

Great explanation - and nice shirt!

@eibhlinb 11 жыл бұрын

Clear & comprehensive...my students thank you!

@000TheMatheus000 8 жыл бұрын

here in brazil the p means potential, the potential of donating Hidrogen atoms.

@kilroy3368 8 жыл бұрын

That makes a lot of sense, I wonder why the rest of the world doesn't?

@___xyz___ 8 жыл бұрын

come to brazil

@rafaeljc12 8 жыл бұрын

gibe money plox

@chloegiraud2582 8 жыл бұрын

+Kilroy 336 in Québec too it's potential

@seantheguy1391 8 жыл бұрын

You spelled hydrogen wrong

@michaelraiwet 9 жыл бұрын

Am I missing something, the pH was 3.5 and the pOH was 10.5. So where did the numbers at 10:06 come from?

@isisshackelford5838 9 жыл бұрын

pH +pOH= 14

@Davalart 11 жыл бұрын

I have just discovered your channel...LOVE IT

@Ahtohallan. Жыл бұрын

This really helped for my final chemistry test tomorrow, Thank you sir!

@avazhalid7129 6 жыл бұрын

The letters pH stand for the French words (pouvoir hydrogène), meaning "hydrogen power"

@abubakrakram6208 9 жыл бұрын

0:43 It's just meant to signify "the power of"? I believe that's how my Chemistry teacher explained it to me. Of course, I'm not sure how much anyone would want to trust his explanation, considering I needed to go online to learn the material. I don't even know why I posted this comment; I'm quite sure Mr. Green knows his material far better than my Chemistry teacher. *EDIT:* He almost immediately says this is a possibility. I probably should have waited until the end to comment.

@nelliesuto8007 5 жыл бұрын

How great would it be if Crash Course created an Organic Chemistry playlist??? IT WOULD SAVE MY LIFE!

@shannonbaker2254 8 жыл бұрын

Senior Chemistry in Australia teaches you that pH stands for parts Hydrogen. Which in my opinion is probably the most logical way of looking at it. Even if it isn't historically accurate.

@boboloconow 10 жыл бұрын

Thank goodness that I have CrashCourse to depend on before my exam

@QUARTERMASTEREMI6 6 жыл бұрын

+John Doe Absolutely! ;) Best resource ever made.

@yousef.al-assaf 8 жыл бұрын

What?! lol. The numbers that you got from your example were 3.5 (pH) and 10.5 (pOH), which their sum is also 14. Late night video, eh!

@ingenuinegalaxies9299 8 жыл бұрын

+Yousef Al-A'ssaf Did you watch the whole video? There is a reason for this. It is why we define a neutral ph 7.

@FouquetJulien 11 жыл бұрын

i suscribed a few weeks ago and i was thinking to my self two days ago, I wonder how exactly acidity/base works on the molecular level. then BAM you show up in my inbox answering exactly what i was wondering. please continue to spy on my brain and answer my questions :D

@jessicajohnson3986 6 жыл бұрын

Chem regents tomorrow, and even though I know we don't need to know too much about this stuff in depth, I started freaking out. I know I can count on CrashCourse to relieve my sudden, absurd lack of knowledge :)

@LuisAntonio-xp4ep 8 жыл бұрын

Pls guys, CrashCourse Physics! plsssss!

@zacharyivanhawkins251 10 жыл бұрын

LOLOL I've never laughed more from watching these videos 8:06

@Qermaq 11 жыл бұрын

I liked the cartoons in this one, especially Katherine pushing you around in the shopping cart. Do you two do that often? That looks like fun.

@nUrDreamZ300 11 жыл бұрын

i cant WAIT for next episode!!

@Adnan-lt5rn 9 жыл бұрын

I'm a simple man, I see Kanye Reference, I thumbs up.

@serene9532 5 жыл бұрын

@ 😂

@user-em4rk4qo1f 7 жыл бұрын

I have to watch these at 0,5 speed in order to understand them properly

@EmmyKhan 7 жыл бұрын

Ah good idea

@noahwhetstone3525 7 жыл бұрын

this may sound crazy but try listening at 2speed. it forces you to really pay attention if you want to understand what is going on and you (might) learn it better.

@sherazkhan2802 7 жыл бұрын

Ihate Mr. Wires How can I slow down the speed on a smartphone ?

@_ashyou 7 жыл бұрын

Sheraz Khan No you can't

@Benny_Blue 7 жыл бұрын

I watch them at 1.25 speed, so I can study more quickly.

@8ytan 11 жыл бұрын

You neglected to mention, Hank, that kW is 1.0E-14 only at 25 degrees Celsius. At different temperatures, the value of kW is different and the pH of pure, neutral water also changes. I think (?) that this also affects the equation pH + pOH = 14 - I'm not 100% sure whether it does but I was always taught to be careful when finding pH from pOH using this method, instead we were taught to use a rearranged form of the kW equation.

@DoctorHutton 11 жыл бұрын

I love the image of Hank shopping with Katherine pushing him in the trolley xD

@Rzkytron 9 жыл бұрын

Emmmm... Crash course math & physics plox :/ ?

@leoneuler1147 9 жыл бұрын

PatrickJMT is an amazing math tutorial channel!

@FireVortex720 9 жыл бұрын

When I dance you give free stuff plox!

@platinumbridge 9 жыл бұрын

FireVortex720 that is some oldschool stuff

@TheRok 8 жыл бұрын

Can't believe there are no high voted comments on “All your base are belong to us!” at 3:09! What, no gamers here? =)

@whitebread7953 8 жыл бұрын

thats a game thing? idk

@talos111 8 жыл бұрын

poorly translated Japanese game.

@whitebread7953 8 жыл бұрын

watts the name?

@IntenseNoobFPS 8 жыл бұрын

zero wing

@whitebread7953 8 жыл бұрын

k thx, i google now

@margaretpitzer6300 11 жыл бұрын

Hey guys, I love your videos. Would you ever be interested in doing a video over Ksp or KI? I know you already did Keq, but it would be a nice refresher. Thanks :)