Buffer solution pH calculations | Chemistry | Khan Academy

Подписаться 227 тыс.

Просмотров 1,1 млн

50% 1

Example of calculating the pH of solution that is 1.00 M acetic acid and 1.00 M sodium acetate using ICE table. Another example of calculating pH of a solution that is 0.15 M ammonia and 0.35 M ammonium nitrate.
Watch the next lesson: www.khanacademy.org/science/c...
Missed the previous lesson? www.khanacademy.org/science/c...
Chemistry on Khan Academy: Did you know that everything is made out of chemicals? Chemistry is the study of matter: its composition, properties, and reactivity. This material roughly covers a first-year high school or college course, and a good understanding of algebra is helpful.
About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content.
For free. For everyone. Forever. #YouCanLearnAnything
Subscribe to Khan Academy’s Chemistry channel: / channel
Subscribe to Khan Academy: ru-vid.com_...

Опубликовано:

22 авг 2014

Ссылка:

Скачать:

Готовим ссылку...

Добавить в:

Мой плейлист

Посмотреть позже

Комментарии : 210

@noahsalomons9687 Год назад

Petition for Khan academy to receive an honorary Nobel prize

@MynameisJapan 7 лет назад

Advice: make sure you have a Ka value. My textbook gave me an intial Kb value and I spent 45 minutes trying to figure out what was wrong. Remember, you can convert Ka to Kb with the expression Ka * Kb =1.0E-14 then simply take the negative log to get Pka! Cheers!

@rojansayami177 6 лет назад

what is E here?

@zijian8147 5 лет назад

actually you can still find pH value by using Kb. if you use Kb value, what you find is pOH. so pH=14-pOH

@demodema5192 4 года назад

Oh man you are a saviour. ThAnks a bunch bro😭😭😭

@seungjunbaek3410 3 года назад

@@rojansayami177 its just the simplified version of 1.0 * 10^-14

@AlgSub22 Год назад

Hi I know its been a year ago. But I just wanted to know that in order to get the Ka, do we must use this expression as CONSTANT? and is it applicable to all related problems of missing the pKa value?

@yx_png 8 лет назад

I had SO many question about Henderson-Hasselbalch equation before I watch this vedio. Thanks a lot. This vedio is really helpful.

@nicaalyssashanearauag8029 2 года назад

RU-vid is my new teacher, thanks a lot!!!!

@rofhiwalivingstone1552 7 лет назад

OMG this is the first time doing biochemistry and people who did it before me kept on saying the calculations part, specifically buffers are hard. Clearly they haven't seen your videos. I love how you work out the questions, the way you explain.. THANK YOU FOR HELPING US.

@psyp2013 2 года назад

I'm graduate from Bachelor of Art by now I'm preparing for an MCAT test . These video series help me get a good score. Thank for Khan academy and AAMC.

@farhansadikabtahifh-6158 8 лет назад

Thanks a lot.You Will be always in my heart

@UTFT27 8 лет назад

Do you play rust?

@johnguillen68 3 года назад

I get the equation and sometimes get the right answer but I really never understood what is actually happening until I watched your video. Thank you

@billipbillip8411 5 лет назад

Perfect explanation, thank you!

@nancyliu5099 7 лет назад

That's very helpful, thanks for uploading this video!

@wafasaliha1552 7 лет назад

thank you so much it's so helpful I wish u r my teacher

@jennifermadrid7221 7 лет назад

Extremely helpful, thank you!

@graceloussakou7345 7 лет назад

So so helpful! thanks, now I don't need to wait for an office appointement with my Biochem professor. Gosh I love our the 21century!

@HoshinoMirai 6 лет назад

I know, and this crams our 2 weeks of stuff into 10 mins of video!

@alessandrac1940 3 месяца назад

Much appreciated. It was a very comprehensive tutorial. In my class i don't have lectures.. it's all from the textbook so i rely on vids like this to get me through

@puretwr899 4 года назад

Khan academy is the best of chemistry in my heart. 👏🏼

@mimi-jt3yg 6 лет назад

Thanks.It's really helpful!

@Manikalens 6 лет назад

This is really helpful... Thanku Sir

@noemiez2076 8 лет назад

thank you very much !! it's very clear now !!

@marcosmoran8835 8 лет назад

extremely helpful, thank you

@oznuryldz8662 3 года назад

It helped me a lot. Thank you.

@Hoxgene 3 года назад

My god. I finally get this. THANK YOU!

@aysuozbek6478 3 года назад

Perfect explanation.Thanks

@xenawu1588 8 лет назад

Great Help!!

@haddadmj96 8 лет назад

Thank you! very useful

@darlingdarling1688 8 лет назад

it was.......so grate full nd awesome

@aisyahAAZ 7 лет назад

LOVED IT

@lazolampapela6190 7 лет назад

Excellent explanation!!!

@sarasherman2662 7 лет назад

This is very helpful.

@isihummetli4671 8 лет назад

thank u so much, dude

@aishan.7703 4 года назад

For the first time in forever my concepts become crystal clear!

@phumudzomamatsiari787 Год назад

brilliant...thnk u so much😇

@Biraj456 7 лет назад

thank u very much sir n khann academy

@bethanyalvarez521 8 лет назад

This video is a lifesaver

@DrCrochetMadeWithLove 3 года назад

Thank u so much

@mpilow9463 7 лет назад

BIG THANKS TO KHAN ACADEMY

@alicemuyeleka2695 Год назад

Thank you very much this is very educative

@wildzach 4 года назад

"Let's say we already know the Ka..." *My professor laughs maniacally*

@NomanKhan-bd4st 3 года назад

lol

@georgemoustakas4030 2 года назад

But it's so easy to calculate Ka if you know the concentrations..

@millionmelesse1518 3 года назад

Thank you so much sir!

@deflationsmc3301 2 года назад

great explanation!

@yumenoritsu 8 лет назад

Thank you!! :DD

@victoroduntan 5 месяцев назад

Thank you for saving a live today.

@nnennaagidi 3 года назад

Thanks a lot sir u saved my life

@user-uf6qx1zk5b Год назад

thanku sir 🙏🏻

@nakatorose7795 3 года назад

Thanks a lot sir all the from Uganda

@GEGE77R6 7 лет назад

thanks teach

@sdghalehbandi16 6 лет назад

Thanksssss😍😍😍😍😍

@nataliaurrutia3882 5 лет назад

holy hell... i actually understand chemistry now; thank you!

@jeroenfranzel3994 6 лет назад

Thank you so much! But what happens when you add 0,24M H3O+ or higher? Because then the Henderson-Hasselbalch equation won't work??

@EddieOverwatch 2 года назад

Thanks my G

@halidsufiyan3663 2 года назад

Thank you for basic concept 👍👍👍🧾

@sylviakazi5629 3 года назад

That's why I always rely on @ Khan Academy!! ☝️☝️😎😁

@keeravyas9849 4 года назад

I am from India we study this in our final sem of school thank you for the best education you provide to us ❤️

@ay_yowtf Год назад

thanks

@joyn.deddeh3291 8 месяцев назад

Thanks for the video. Really helpful but how did u get the Ka value tho?

@wryder156 3 года назад

thank you :)

@codeonline9577 8 лет назад

For the situation where we added acid to our buffer, why is the procedure the same as when we added base to our buffer since in the case of adding acid, the chemical equation on screen is a base dissociation equation which would use Kb, while the Henderson-Hasselbach equation is derived from acid dissociation?

@torchlight3145 7 лет назад

Good explanation but how can you come up with the chemical equation? I'm having a hard time creating the equation hELP

@esa2236 7 лет назад

The chemical equation is pH = pKa + log([conjugate base]/[weak acid]). The best time to use this is when you're dealing with a buffer problem involving an acid with its conjugate base or a base with its conjugate acid.

@judypark8977 7 лет назад

I think that they're talking about like the ACTUAL equation. Like the __ + __ --> __ +__. If it isn't, can you help me with finding that equation?

@n7pako367 6 лет назад

That is the one

@comoelitamelendez8467 4 года назад

@@esa2236 Great side note about when is the best time to use Hendnerson Hasselbach equation. ;)

@laxsplash78 Год назад

Sameee that’s the part that’s messing me up

@brittanykosterlytzky7248 4 года назад

how would you find the ka if you were using something like sodium benzoate or benzoic acid

@AhsanKhan-eb2zb 7 лет назад

Nice

@quantum_psi 8 лет назад

Thanks! Think it's starting to make some more sense, although i don't understand why the hydronium gets canceled out/"used up"

@skarpengland 8 лет назад

+Sebastian Gulbransen just think about it, the hydrogen binds to NH3 to form NH4+, and the Cloride will dissolve easily with the H2O in the solution. It becomes a spectator ion. this is why we wanna stay with K, Na, and other metals in easily dissolved salts to add to buffers, they dissolve easily.

@skarpengland 8 лет назад

+Elektro Techniek Haha wow, i do NOT know what i was thinking when i wrote my answer xD haha i am out, i wrote about spectator ions, whaat the hell xD

@athena7417 8 лет назад

+lasse skarpengland lol this cracked me up

@mizramontana8000 3 года назад

Lets see who's here in 2021 👍👍😊

@KingCarl36 7 лет назад

test Wednesday, thanks

@sarahfaress5957 6 лет назад

I get why you divided the 0.05 molNaOH/0.50L to find the molarity, but why is the same not done for the buffer componenets? we have only 0.50 L of solution, so shouldn't the concentration of NH3 be 0.50 L(0.24mol)/1L ? and then add to it the 0.01M of NaOH?

@NCBrianS 6 лет назад

Im having a hard time between knowing when to do it this way vs using the common ion and ICE method as both problems seem pretty similar at first in terms of approach. Any advice?

@owensmith3940 2 года назад

they are essentially the same thing. If you notice, in this video, he is creating an ice table. With initial concentration, then the change, and the result

@owensmith3940 2 года назад

after the first problem, of course

@kochosks Год назад

U need ICE for Common ion, so to look for concentration, it is easier to go with common ion. Other than that, u can opt for Henderson-Hasselbalch or buffers equation. Pretty convenient:))

@mak1x3 4 месяца назад

and what about the additional concentration of NH4+ that is produced when NH3 is dissolved?

@moristhetiger 7 лет назад

to solve these questions what I think is that we need to be very thorough with all the assumptions... okay so like HCl donates proton to ammonia via irreverservible reactions , sorry if I am being too much but its important as far as I can see :-/

@KenyanLondonor 7 лет назад

how do you find pKa or its constant as 5.6 * 10 to power -10

@Hellamoody 7 лет назад

constant is usually given

@RickRudy 10 месяцев назад

Behold: The Preventer of Mental Breakdowns

@abdulfattahmuhammad3923 3 года назад

Tell us that... how to calculate ph Of buffer with out Hasselbalch equation

@paulrodriguez2901 2 года назад

May I ask, will it be always H30 whenever we compute for addition of base or acid?

@AVADHESHCHAUHAN01091995 4 года назад

Please calculate the ph of Tris buffer solution

@saddamhussain9618 6 лет назад

salam sir. sir you didnt mention the volume of 0.005 M NaOH and also of acid HCl

@fehimaa1609 2 года назад

10Q teacher

@belle8606 2 года назад

Thaaaaaaaaaaank youuuuuuuu

@successwokili 8 лет назад

can this be formulae replace ice table in finding the ph of a buffer solution?

@ariaarmstrong2487 4 года назад

how do you know which species in solution will be used up? for example in one of the problems you say all of the acid will react so we subtract that concentration in the "change" row of the ice table.

@ariaarmstrong2487 4 года назад

BUT WHY

@aestheticxgirll 2 года назад

Are we supposed to learn the dissociation constant Ka value?

@saucemonster7137 Год назад

ik i probably wont get a reply for like 5 years but for problems where a strong acid/base is added to a buffer (2:51 and 7:19), shouldn't the concentrations change after the strong base reacts with some of the weak acid (or vice versa) because of the equilibrium? do we just not consider this because the Ka value is usually very low? if it's not very low, should we draw an ICE table after calculating the effect of the strong reactants?

@MuhammadShafiq-jc7rx Год назад

Sir How you put the value of salt on the place of base in numerical 1 . Did not get that please clarify that sir.

@christinemukuni5608 2 месяца назад

What if we dont already know the Ka value and it is not given in the question as well

@mahmoudemadeddin Год назад

for this question 2:54 why all of this just go with moles and add them to the base and remove from the acid, more easier! pH = 9.25 + lg (0.12+0.005 / 0.1 - 0.005 ) = 9.369

@nurhusna1407 4 года назад

How to know when NH4+ donate or accept proton? Also why does 4:24 NH3 doesn't have a +?

@martinfederico7269 7 лет назад

Why did it react 100% of the added OH- with NH4+ and not according to NH4+ Ka ?

@pink_floyd1 5 лет назад

Ka is for NH4--NH3+H+ for this equilibrium reaction and not for NH4OH

@muddassirrehman4623 7 лет назад

How we can directly find the pOH of basic buffer?

@leoningman62 3 года назад

Why did you plus the second time you use the HH equation? Since it is pka-log(HA/A^-) ? I do not understand

@fadhladel247 6 лет назад

But why you did not use the following equation and you had weak base with it is salt?? PoH=Pkb+log (salt)/ (base) And thank you alot.

@AmeliaKhairi 6 лет назад

right????

@hriturajdas224 4 года назад

Ikr.

@yejichaeryeong5545 2 года назад

What happen if HCl. Is added to NaCl? Does it affect the NaCl's PH

@user-mn4hr1ll1u 6 месяцев назад

Hi sir how do u get the the ka for the solution ? Is it a constant value. I thought the salt was suppose to be divided by the base? Am not quite sure any one who could pls explain it better pls it's urgent

@rish_official1934 6 лет назад

Not sure if its correct but here in Singapore they taught us that the NH3/NH4Cl pair is a congugate base pair, as NH3 acts as a weak base when it ionises in water to give NH4+ and OH-. So our subsequent calculations would include the PKb instead of Pka and finding pOH first then pH, but i still end up with the same values as you do for my final answer. So does NH3/NH4Cl pair act as a congugate base pair or as a congugate acid pair? Thanks

@mariya1941 Год назад

Its still a base buffer the fact that in relative terms its conjugate is termed as acid n it can be put in the same equation using ka still gives the same ans

@mhmdageeli9974 5 лет назад

What is this program you are using in your videos

@tyronwood2231 6 лет назад

how do you get the equation? why would it not be NH4+ + H20 ---> NH3 + H30+?

@diver4573 6 лет назад

I would like to know the preparation of 0.2 M phosphate buffer preparation ph 8 . Components we have are sodium phosphate dibasic and sodium dihydrogen phosphate ???????~

@bradley7118 6 лет назад

So you’re telling me, we have to look up the pka in order to do this problem?

@Music-zx4po Год назад

What would the pH without the buffer be?

@mikeyyychang8402 7 лет назад

i think last one is wrong sice Ka=salt/acid (not too sure

@patrickstar7693 2 года назад

It gets always talked about the addition of a strong acid or strong base... my question would be how to calculate the ph with the addition of a weak acid? Lets say the addition of acetic acid to a phosphate buffer