pH and pOH: Crash Course Chemistry #30

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  • Опубліковано 17 січ 2025

КОМЕНТАРІ • 1,1 тис.

  • @crashcourse
    @crashcourse  4 роки тому +112

    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

  • @anchitrao7374
    @anchitrao7374 8 років тому +1026

    These videos are ridiculously well made

    • @krishnagoli687
      @krishnagoli687 5 років тому +24

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

  • @Spycyzygy
    @Spycyzygy 9 років тому +351

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

  • @daiwikdhar6464
    @daiwikdhar6464 5 років тому +397

    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!!!

  • @foxyred3216
    @foxyred3216 10 років тому +497

    "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
      @kristina1463 5 років тому +16

      THANK YOU

    • @rhythmthukral7857
      @rhythmthukral7857 5 років тому +3

      Shut up

    • @ScareSans
      @ScareSans 5 років тому +59

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

    • @pollenbunal2101
      @pollenbunal2101 5 років тому +2

      Arceus The God Pokemon Hahahahahhahahah

    • @aigle_grincheux
      @aigle_grincheux 5 років тому +8

      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 💜💜

  • @drew.k2385
    @drew.k2385 7 років тому +206

    "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?

  • @nickracca1993
    @nickracca1993 6 років тому +108

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

  • @pilotmoyafan
    @pilotmoyafan 10 років тому +468

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

    • @1nfo663
      @1nfo663 5 років тому +20

      did u pass

    • @Tutti22
      @Tutti22 5 років тому +2

      Nameless lol

    • @shaisblind
      @shaisblind 5 років тому +10

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

    • @pcrd38
      @pcrd38 5 років тому +2

      Howd ya do man?

    • @ctsvblk
      @ctsvblk 4 роки тому +2

      ShadowBIRD maybe he died.. like actually

  • @IndeedJoe
    @IndeedJoe 11 років тому +1727

    finals anyone?

  • @MasterGus501
    @MasterGus501 11 років тому +1017

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

  • @MagicallyEmily
    @MagicallyEmily 11 років тому +77

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

  • @fluffy3355
    @fluffy3355 4 роки тому +87

    god i hate how chemistry has so much vocabulary

  • @jessjms1181
    @jessjms1181 9 років тому +638

    Why is water so cute

    • @jessjms1181
      @jessjms1181 8 років тому +53

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

    • @braveheart3847
      @braveheart3847 8 років тому +11

      lol

    • @dmoneyswagg64
      @dmoneyswagg64 7 років тому +15

      Dan Vegas why did I like this comment?

    •  6 років тому +11

      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
      @chemistrychannel5021 6 років тому +14

      Because it's bent 😂

  • @windowsxboxguy
    @windowsxboxguy 8 років тому +93

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

  • @storyspren
    @storyspren 9 років тому +15

    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
    @SWEm4rt1n 11 років тому +27

    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
    @riyasingh7287 9 років тому +293

    Can we have CrashCourse Physics? :/

  • @josiahklein70
    @josiahklein70 8 років тому +433

    Crash Course Mathematics, anyone?

  • @2357y1113
    @2357y1113 11 років тому +6

    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
    @JuiceCarver 10 років тому +36

    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!!

  • @BJB104
    @BJB104 2 роки тому +1

    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..

  • @Abominatrix650
    @Abominatrix650 8 років тому +38

    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.

  • @hazzacookiemofo
    @hazzacookiemofo 10 років тому +9

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

  • @itskankan
    @itskankan 11 років тому +8

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

  • @Sophie-wf3ex
    @Sophie-wf3ex 8 років тому +139

    "...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
      @jungsooneul8879 7 років тому +3

      I thought so too...

    • @miav2046
      @miav2046 7 років тому +12

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

    • @arianasanchez4746
      @arianasanchez4746 7 років тому

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

    • @ScholaBayBee
      @ScholaBayBee 7 років тому

      sameee

    • @plazmavolt1238
      @plazmavolt1238 6 років тому

      yeah...

  • @PerryTheGangsta
    @PerryTheGangsta 8 років тому +11

    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.

  • @Valdagast
    @Valdagast 7 років тому +50

    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.

  • @PartyChicken407
    @PartyChicken407 11 років тому +12

    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.

  • @f0gman_
    @f0gman_ 11 років тому +4

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

  • @xXgracexX333
    @xXgracexX333 11 років тому +11

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

  • @krisxcross
    @krisxcross 10 років тому +4

    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

  • @allenhoggan7675
    @allenhoggan7675 5 років тому +19

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

  • @nmubunny5395
    @nmubunny5395 10 років тому +5

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

  • @ScarecrowWoods
    @ScarecrowWoods 11 років тому +58

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

  • @nelliesuto8007
    @nelliesuto8007 6 років тому +1

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

  • @ScareSans
    @ScareSans 5 років тому +5

    "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

  • @DoctorSkater
    @DoctorSkater 11 років тому +2

    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 :).

  • @neutralpresident4361
    @neutralpresident4361 10 років тому +245

    My pH would be 7 because I'm neutral.

    • @FROPDESAI
      @FROPDESAI 9 років тому +8

      Neutral President Neutral President is neutral.

    • @darraghbrennan8549
      @darraghbrennan8549 7 років тому +4

      Neutral President ii

    • @mihajlojovanovic7651
      @mihajlojovanovic7651 6 років тому +33

      Mine would be 14 cause I'm basic

    • @tobey1684
      @tobey1684 6 років тому +2

      @@mihajlojovanovic7651 lol

    • @mollyhorse
      @mollyhorse 5 років тому +1

      @@mihajlojovanovic7651 and caustic! Lol

  • @jbkjbk1999
    @jbkjbk1999 9 років тому +120

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

    • @MrInsdor
      @MrInsdor 9 років тому +14

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

    • @eliotoboyce5738
      @eliotoboyce5738 9 років тому +9

      +MankeyFrankie GöØd fØr ü

    • @landonhillyard
      @landonhillyard 9 років тому +2

      +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
      @IhaveCupcakes 8 років тому +1

      +Totally Not A Cylon I must agree

  • @19U91-l6s
    @19U91-l6s 8 років тому +8

    You save lives man!...🙌🏻🙌🏻

  • @jeffshubert
    @jeffshubert 11 років тому +3

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

  • @MegaMike327
    @MegaMike327 7 років тому +10

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

  • @rithwiqnair537
    @rithwiqnair537 9 років тому +1

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

  • @shannonbaker2254
    @shannonbaker2254 9 років тому +3

    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.

  • @manimaima
    @manimaima 11 років тому +2

    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!

  • @bvbandiss
    @bvbandiss 9 років тому +3

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

  • @justinhill6206
    @justinhill6206 11 років тому +1

    to who ever matched the musical genres to the pH states you are a genius nice work

  • @TheMisleduser
    @TheMisleduser 6 років тому +34

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

  • @BlooregardQKazoo-ff6wb
    @BlooregardQKazoo-ff6wb 11 років тому +1

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

  • @metadolle8925
    @metadolle8925 8 років тому +40

    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
      @makeitmusical 8 років тому +6

      +Josie Serpan Strangely, this helped me.

    • @metadolle8925
      @metadolle8925 8 років тому +2

      Sarah Hudak Awesome, glad to hear it XD

    • @h6ly
      @h6ly 6 років тому

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

    • @ScareSans
      @ScareSans 5 років тому +2

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

  • @8ytan
    @8ytan 11 років тому +1

    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.

  • @pri7974
    @pri7974 9 років тому +4

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

  • @IllyaLeonovMorganFreepony
    @IllyaLeonovMorganFreepony 11 років тому +1

    Lower case p is used to represent a negative log of the hydronium ion concentration. The pH scale is logarithmic.

  • @nicktimmerman8562
    @nicktimmerman8562 5 років тому +8

    0.5 speed and I couldn't stop crying

  • @Syntaxxed
    @Syntaxxed 2 роки тому +1

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

  • @thelark2049
    @thelark2049 9 років тому +10

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

  • @JonathanDery
    @JonathanDery 11 років тому +1

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

  • @premgill2699
    @premgill2699 8 років тому +14

    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
      @veditababuta4201 8 років тому +2

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

  • @Dixavd
    @Dixavd 11 років тому +1

    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).

  • @shereitograce7844
    @shereitograce7844 9 років тому +9

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

  • @JoshuaLoganjoshuadlogan
    @JoshuaLoganjoshuadlogan 11 років тому +2

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

  • @linguaphilly
    @linguaphilly 9 років тому +4

    Haha that 'ohhhh'-moment at 6:28

  • @captainsmurk
    @captainsmurk 11 років тому +1

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

  • @HarryBungholio
    @HarryBungholio 10 років тому +9

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

  • @dragonbalism
    @dragonbalism 11 років тому +1

    The opposite logarithm of the concentration of the H+ ion and OH- ion are inversely proportional, and this proportion makes the both of them add up to 15

  • @rachelgordon8330
    @rachelgordon8330 10 років тому +11

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

  • @meganyamamoto31
    @meganyamamoto31 10 років тому +1

    4:40 H20 -> H30+ + OH-
    Not sure if anyone else has pointed this out but I don`t think this is balanced. It looks like a hybrid equation of H2O -> H+ + OH- and 2H20 -> H3O+ + 2OH- ?

  • @rex17ly62
    @rex17ly62 4 роки тому +3

    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.

  • @samanthalee36
    @samanthalee36 11 років тому

    I'm glad I'm not the only one who feels the need to correct Crash Course chemistry videos. I haven't been watching in a while, so I had hoped they had gotten less sloppy.

  • @000TheMatheus000
    @000TheMatheus000 9 років тому +62

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

    • @kilroy3368
      @kilroy3368 8 років тому +1

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

    • @___xyz___
      @___xyz___ 8 років тому +6

      come to brazil

    • @rafaeljc12
      @rafaeljc12 8 років тому +1

      gibe money plox

    • @chloegiraud2582
      @chloegiraud2582 8 років тому

      +Kilroy 336 in Québec too it's potential

    • @seantheguy1391
      @seantheguy1391 8 років тому +1

      You spelled hydrogen wrong

  • @stevenn2382
    @stevenn2382 7 років тому +2

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

  • @avazhalid7129
    @avazhalid7129 6 років тому +3

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

  • @recklessroges
    @recklessroges 11 років тому

    Great video, (as always). What might confuse some people is that the word "base" is used in three different ways in this video: Chemistry: base as the opposite of an acid, Math: base 10 logarithms, and geek-cultural-reference: "All your base are belong to us" which refers to a military encampment. We just need to know who is on first to be really confused. "What pH does a log of base 10 have on your base?"

  • @Adnan-lt5rn
    @Adnan-lt5rn 9 років тому +29

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

  • @MD-nf5rr
    @MD-nf5rr 5 років тому +2

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

  • @johndou423
    @johndou423 6 років тому +12

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

  • @TushitDesai
    @TushitDesai 9 років тому

    ultimate presentation

  • @boboloconow
    @boboloconow 11 років тому +4

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

    • @QUARTERMASTEREMI6
      @QUARTERMASTEREMI6 6 років тому

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

  • @Latnii
    @Latnii 11 років тому +1

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

  • @PinkLove961
    @PinkLove961 10 років тому +5

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

  • @Froggeh92
    @Froggeh92 11 років тому +1

    Yes. the pH lets you know how Acidic/Basic your product is. The more balanced the formula the more gentle it is on your skin/hair and is friendlier for daily use.

  • @LuisAntonio-xp4ep
    @LuisAntonio-xp4ep 9 років тому +3

    Pls guys, CrashCourse Physics! plsssss!

  • @ellagruel8227
    @ellagruel8227 10 років тому +1

    The Katherine pushing Hank in a grocery cart made my day.

  • @abubakrakram6208
    @abubakrakram6208 9 років тому +4

    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.

  • @cutescience2109
    @cutescience2109 11 років тому +1

    Delightful explanation of something we hear about all the time. I love that you start out by telling us that you are not "that into personal grooming!" Cute!

  • @yousef.al-assaf
    @yousef.al-assaf 9 років тому +14

    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
      @ingenuinegalaxies9299 8 років тому +3

      +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.

  • @Qermaq
    @Qermaq 11 років тому

    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.

  • @TheRok
    @TheRok 8 років тому +54

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

  • @DoctorHutton
    @DoctorHutton 11 років тому +2

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

  • @zacharyivanhawkins251
    @zacharyivanhawkins251 11 років тому +3

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

  • @gwendance
    @gwendance 11 років тому +1

    At 01:42 where it says that Hank is a mass of incandescent gas, is that a reference to the "Why the Sun Burns" by They Might Be Giants?

  • @Rzkytron
    @Rzkytron 10 років тому +33

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

    • @leoneuler1147
      @leoneuler1147 10 років тому +4

      PatrickJMT is an amazing math tutorial channel!

    • @FireVortex720
      @FireVortex720 10 років тому +5

      When I dance you give free stuff plox!

    • @platinumbridge
      @platinumbridge 9 років тому +1

      FireVortex720 that is some oldschool stuff

  • @eibhlinb
    @eibhlinb 11 років тому +1

    Clear & comprehensive...my students thank you!

  • @user-em4rk4qo1f
    @user-em4rk4qo1f 8 років тому +29

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

    • @EmmyKhan
      @EmmyKhan 8 років тому

      Ah good idea

    • @noahwhetstone3525
      @noahwhetstone3525 8 років тому +8

      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
      @sherazkhan2802 8 років тому

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

    • @_ashyou
      @_ashyou 8 років тому +2

      Sheraz Khan No you can't

    • @Benny_Blue
      @Benny_Blue 7 років тому +2

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

  • @world-suppliers
    @world-suppliers 8 років тому +1

    this help mr alot with understanding saponification , god bless you

  • @allypeccia7699
    @allypeccia7699 8 років тому +6

    Doesn't the water dissociation constant change with respect to temperature?

  • @pixelatedbrœ
    @pixelatedbrœ 11 років тому

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

  • @BrixoRamas
    @BrixoRamas 5 років тому +5

    Hey did you know? Nemo is Latin for nobody. So Finding Nemo is........ Finding nobody

  • @mollyhorse
    @mollyhorse 5 років тому +1

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

  • @taskd9146
    @taskd9146 9 років тому +8

    Did I just see KANYE WEST at 1:03 .