pH and pOH: Crash Course Chemistry #30
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- Опубликовано: 8 сен 2013
- 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
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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
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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
YAY
Yay
My chemistry teacher described the water to hydronium and hydroxide as water being so bored that it reacts with itself
lol
+aung Oo ROFLLMAO
Rsaramallac Mine too!
Rsaramallac e
Me
These videos are ridiculously well made
Damn they'd be really helpful if they went just a bit more into detail but nonetheless amazing production quality
"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.
THANK YOU
Shut up
@Rythm Thukral you misspelled "you're welcome"
Edit: Jesus I'm an idiot, I meant you misspelled thank you
Arceus The God Pokemon Hahahahahhahahah
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 💜💜
"ok so now that you're terrified, I'm here to help"
-hope someone told me that word earlier.
god i hate how chemistry has so much vocabulary
I'm still kinda screwed for the test tomorrow....
did u pass
Nameless lol
lol, some guy replies 5 years ago, someone replies 5 days ago..😆
Howd ya do man?
ShadowBIRD maybe he died.. like actually
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!!!
finals anyone?
You know it :D
Sadly my finals are way above the the stuff in this video
hi Unfortunately, me too
Yep it got me too
Pff, yes
Why is water so cute
Dan Vegas I don't remember why I said it to be honest
lol
Dan Vegas why did I like this comment?
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
Because it's bent 😂
"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?
Man, you're great at chemistry! Have you ever considered cooking crystal meth?
Hankenburgh.
Gus F breaking bad refrence. lol.
BREAKING BAD.
most heard sentence of a chemist
Cooking cocaine is much better
this the type of guy to help me pass my test tomorrow
I honestly understand chemistry better through these videos than I do through my actual college chemistry course. Thanks, Hank!
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.
Crash Course Mathematics, anyone?
ya
Yea
Josiah Klein yes please
Yes, Please! He makes everything way more fun.
Josiah Klein Yeees
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
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.
It is 7.4 written in my book
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.
I love all of the pop culture references in the show, like Deadmau5 when Hank was talking about Strong Bases
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.
Can we have CrashCourse Physics? :/
They alrdy have it but it's not Hank doing it
Riya Singh have you even searched it?
It is there, search it
I come from the future, they've already done it, enjoy!
careful what you wish for
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..
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!
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
Deadmau5 was the last thing I was expecting to see in Crash Course XD
Thank you so much Hank! This crash course actually helps me a lot in school.
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 :).
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!!
Your videos are really helping me with my MCAT, thank you so much!!!
My pH would be 7 because I'm neutral.
Neutral President Neutral President is neutral.
Neutral President ii
Mine would be 14 cause I'm basic
@@mihajlojovanovic7651 lol
@@mihajlojovanovic7651 and caustic! Lol
"...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.
I thought so too...
i caught that too and threw me off. kept rewinding thinking I missed something, at least our answers 3.5+10.5=14
Damn. I'll look for another video to study 😭😭
sameee
yeah...
Universities should uses CrashCourse as it was way more interactive then Khan.
i have no idea what im watching
i think my brain is melting
know how you felt....uffff
This is a great video series. Thank you for taking the time to make this!
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!
Great job Hank! It would be interesting to learn about the dissolving powers of really strong acids.
These videos have helped me so much in my chemistry class. Thank you 😊😊😊
Thank you so much! We went over this in chem and I thought I knew it well but this explanation helped me much more!
That kanye power thing was the best thing I've seen on youtube this week! Keep up the creativity :)
English speakers trying to pronounce Ø, Æ and Å never gets old.
He does it pretty well though, ä ö and ü mostly get "ignored" and will be pronounced as a o and u : ^)
+MankeyFrankie GöØd fØr ü
+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.
+Totally Not A Cylon I must agree
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.
You save lives man!...🙌🏻🙌🏻
I'm such a huge fan of this guy and these videos! Awesome.
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.
"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
it was one of the first "memes"
This is exactly what I am going through in school right now! This has really help me thanks.
Love these videos! Love love love! Makes me laugh while I am learning...thanks!
can't lie. I should have been watching these instead of reading the text
My chem teacher is awful...she should honestly just show these videos!!! They help me so much to understand! Thank's Hank!!!!
I love the image of Hank shopping with Katherine pushing him in the trolley xD
Thank you for this! I was in desperate need to understand pH and OH junk. Just in time as always, Hank!
pH stands for: "potentia Hydrogenii" which is a newlatin word.
0.5 speed and I couldn't stop crying
you're good at this man, keep it up!
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).
I was taught that pH came from French: pouvoir Hydrogene. Like, the ability to release the hydrogen ion and create hydronium ions...
Wish my chem teacher taught half as good as Hank teaches.
Btw Please bring crash course physics soon :))
'so now that you're terrified" exactly my reaction when my teacher introduced pH and pOH without explaining us logarithms lol
this help mr alot with understanding saponification , god bless you
Haha that 'ohhhh'-moment at 6:28
Kw is only 1.0*10^-14 at 25 degrees celsius tho
I literally almost had a mental break down in class yesterday. Today I find this goldmine! Life is really good LOL
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
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.
That' what I thought too, I watched the that part over 4 times to make sure.
You explain chemistry so well. I feel I have won a higher level of knowledge
Helped me a lot.... Doing great Hank Green!
How great would it be if Crash Course created an Organic Chemistry playlist??? IT WOULD SAVE MY LIFE!
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!"
+Josie Serpan Strangely, this helped me.
Sarah Hudak Awesome, glad to hear it XD
well tbh p stands for power and H stands for hydrogen, im no scientist but pH is the power of Hydrogen
@Jordan_acidic Hank himself said we could not confirm if pH means power of Hydrogen.
pH and pOH stand for potency (p) of hyrdogen, (H) and potency (p) of hydroxide (OH), according to my chemistry teacher with a phD. (
I just realised... I've been watching Crash Course since hte begining! Thanks for making me realise that, Hank!
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 :)
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?
pH +pOH= 14
The letters pH stand for the French words (pouvoir hydrogène), meaning "hydrogen power"
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.
Lower case p is used to represent a negative log of the hydronium ion concentration. The pH scale is logarithmic.
here in brazil the p means potential, the potential of donating Hidrogen atoms.
That makes a lot of sense, I wonder why the rest of the world doesn't?
come to brazil
gibe money plox
+Kilroy 336 in Québec too it's potential
You spelled hydrogen wrong
Pls guys, CrashCourse Physics! plsssss!
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.
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 :)
LOLOL I've never laughed more from watching these videos 8:06
Thank goodness that I have CrashCourse to depend on before my exam
+John Doe Absolutely! ;)
Best resource ever made.
My mind is blown ! :-O
I was thought in school that the p in pH stood for percentage of hydrogen, from its point of saturation. I never pushed the issue much past that point, though the numbers made little sense. The explanation of the scale and the related numbers helped a lot to correct my misunderstanding. But, foremost, I had the misconception of believing that the hydrogen ions floated is solutions and even organisms and that it accounted for some of the heat (through infrared light) that is emited by those. The scientific community should realy make an effort to point out more clearly that hydrogen ions are way to reactive to permeate solutions and organisms, but rather that they are usually bound to other nearby molecules or elements right away. The word hydronium is so rarely used that it promotes misunderstanding, probably from a lot of students and simple fans of science like myself. Thanks to all for this clarification !
to who ever matched the musical genres to the pH states you are a genius nice work
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!
+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.
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.
Well, I can help you with one thing. Although I saw one reference to pH standing for "Potential Hydrogen", what I was taught long ago makes a lot more sense. That it stands for Particles of Hydrogen, which is reasonable given that it's particles of the Hydrogen atom that are causing the pH to change.
Clear & comprehensive...my students thank you!
Just want to say thank you for helping me understand chemistry. I wish you were my teacher. Or that I could just watch RUclips videos in my class rather than listen to a professor who cant explain anything. You rock. Thank you.
I'm a simple man, I see Kanye Reference, I thumbs up.
@ 😂
The Katherine pushing Hank in a grocery cart made my day.
This really helped for my final chemistry test tomorrow, Thank you sir!
I have to watch these at 0,5 speed in order to understand them properly
Ah good idea
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.
Ihate Mr. Wires How can I slow down the speed on a smartphone ?
Sheraz Khan No you can't
I watch them at 1.25 speed, so I can study more quickly.
Emmmm... Crash course math & physics plox :/ ?
PatrickJMT is an amazing math tutorial channel!
When I dance you give free stuff plox!
FireVortex720 that is some oldschool stuff
Loved the reference to All Your Base Are Belong to Us!
Haha Katherine pushing Hank in the shopping cart is great XD
Did I just see KANYE WEST at 1:03 .
+taskaran dhaliwal Yes.
Frank Underwood i
Can't believe there are no high voted comments on “All your base are belong to us!” at 3:09! What, no gamers here? =)
thats a game thing? idk
poorly translated Japanese game.
watts the name?
zero wing
k thx, i google now
Thank you so much, this is amazing
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.