Check this out. [anything] = n x 10^(m) p[anything] = (n-1).(10-m) So in the video, Ka= 1.8 x 10^(-5) = [H3O+] p[H3O+]= (5-1).(10-2) [don't include negative & round). pH= 4.8 ~4.74 Learned this through a MCAT Kaplan Video, so the credit goes to them! You can use this for anything...so if you're given Ka and need to get the pKa, or the pOH and you know the [OH]. Very handy for fast calculations. You can always to the long-log method for an accurate answer.
Y'all *demanding* a solution without calculator should really be ashamed not to appreciate the work this man is doing. If you want to know how to approximate the value of pH, that's not something that the chemistry video must necessarily cover. Go search TH-cam for a video on logarithms.
hunter sikari No we can only assume x is a small value only when ka < 1 for example : 1.83x10^-4, we ignore x since the degree of ionization is very small ( less than 5%) and ka < 1 where as if ka = 6.73x10^3 , we have to include x in the equation since ka > 1 and degree of ionization is greater than 5%
How can we equate Ka = [CH3COO-][H3O+]/[CH3COOH] what I have learnt Is this [CH3COO-][H3O+]/[CH3COOH] = Kh (i.e hydrolysis constant) and Kh = Kw/Ka. And from here we calculate x and then [H3O+] = x. And then pH = - log (x).
i know this is old but another way to get [H3O+] is using: [OH-][H3O+] = Kw so, [H3O+] = Kw/[OH-] Kw is constant: 1.01 x 10^-14 now u can use the -log[H+]
that works too. For example the second problem whose PH was 8.89. You could have use kw/kb to find Ka and then the solution is simply PH = -log(5.56 x 10^10) + log (0.15/0.35) will give you the 8.89 PH he found without having to go through all of those steps . It is good to know the ICE method solution however
You cannot use a calculator on the MCAT. You should show people how to best approximate these values. Example: -log(m x 10^-n) = approx. n - 0.m. So for this video -log (7.7 x 10^ -6) = 6- 0.77 = 5.23
These are AAMC approved videos and given that use of calculator is not permitted in the exam, is it the time you showed your viewers how to solve these problems WITHOUT a calculator?
If ye then be risen with Christ, seek those things which are above, where Christ sitteth on the right hand of God. Set your affection on things above, not on things on the earth. For ye are dead, and your life is hid with Christ in God. When Christ, who is our life, shall appear, then shall ye also appear with him in glory. Mortify therefore your members which are upon the earth; fornication, uncleanness, inordinate affection, evil concupiscence, and covetousness, which is idolatry: For which things' sake the wrath of God cometh on the children of disobedience: In the which ye also walked some time, when ye lived in them. But now ye also put off all these; anger, wrath, malice, blasphemy, filthy communication out of your mouth. Lie not one to another, seeing that ye have put off the old man with his deeds; And have put on the new man, which is renewed in knowledge after the image of him that created him: Where there is neither Greek nor Jew, circumcision nor uncircumcision, Barbarian, Scythian, bond nor free: but Christ is all, and in all. Put on therefore, as the elect of God, holy and beloved, bowels of mercies, kindness, humbleness of mind, meekness, longsuffering; Forbearing one another, and forgiving one another, if any man have a quarrel against any: even as Christ forgave you, so also do ye. And above all these things put on charity, which is the bond of perfectness. And let the peace of God rule in your hearts, to the which also ye are called in one body; and be ye thankful. Let the word of Christ dwell in you richly in all wisdom; teaching and admonishing one another in psalms and hymns and spiritual songs, singing with grace in your hearts to the Lord. And whatsoever ye do in word or deed, do all in the name of the Lord Jesus, giving thanks to God and the Father by him. Wives, submit yourselves unto your own husbands, as it is fit in the Lord. Husbands, love your wives, and be not bitter against them. Children, obey your parents in all things: for this is well pleasing unto the Lord. Fathers, provoke not your children to anger, lest they be discouraged. Servants, obey in all things your masters according to the flesh; not with eyeservice, as menpleasers; but in singleness of heart, fearing God: And whatsoever ye do, do it heartily, as to the Lord, and not unto men; Knowing that of the Lord ye shall receive the reward of the inheritance: for ye serve the Lord Christ. But he that doeth wrong shall receive for the wrong which he hath done: and there is no respect of persons. Colossians 3 KJV bible.com/bible/1/col.3.0.KJV
There are a lot of terms that you have to learn before watching this video. Maybe you are confused because you don't know the definition of some of the terms (le Chatlier's principle, equilibrium, shift, etc.)
+Parth Ranawat pH is a measure of how acidic/basic water is. The range goes from 0 - 14, with 7 being neutral. pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base. Got this from google.
Thank you. Really learn more here than lessons.
Wooow thanks Khan Academy. I have always had troubles in this topic. Now am happy I have followed
Check this out.
[anything] = n x 10^(m)
p[anything] = (n-1).(10-m)
So in the video,
Ka= 1.8 x 10^(-5) = [H3O+]
p[H3O+]= (5-1).(10-2) [don't include negative & round).
pH= 4.8 ~4.74
Learned this through a MCAT Kaplan Video, so the credit goes to them! You can use this for anything...so if you're given Ka and need to get the pKa, or the pOH and you know the [OH]. Very handy for fast calculations. You can always to the long-log method for an accurate answer.
You're a god.
Thank you so much
Y'all *demanding* a solution without calculator should really be ashamed not to appreciate the work this man is doing. If you want to know how to approximate the value of pH, that's not something that the chemistry video must necessarily cover. Go search TH-cam for a video on logarithms.
I swear you and organic chem tutor have the lowest volume videos on youtube.
I guess it depends on the speakers on your device. It's loud on mine.
yess I agreed. But they are the best tutors
Organic chemistry is the best
thank you so much khan academy! this helped a great deal! :-))
10:56 Can we assume every time that the x is of a very less value?
THank u for the video!
yah +hunter sikari
hunter sikari No
we can only assume x is a small value only when ka < 1
for example : 1.83x10^-4, we ignore x since the degree of ionization is very small ( less than 5%) and ka < 1
where as if ka = 6.73x10^3 , we have to include x in the equation since ka > 1 and degree of ionization is greater than 5%
That is obviosly idiot
Sayam Bandyopadhyay obvious, idiot.*
Idiot.
lol
Yaaaas, thank you!
Thank you!! never knew it was this easy
thank you, this video was so helpful ! :)
Henderson Hassleback equation will be your friend with these type problems. PH= Pka+log ([conjugate base]/[acid])
when I did CA/A I did NH3/NH4 and got the wrong answer but when I did the reverse got the correct. Anyone know why?
Excellent, thanks!
Thank you...
How can we equate Ka = [CH3COO-][H3O+]/[CH3COOH]
what I have learnt Is this [CH3COO-][H3O+]/[CH3COOH] = Kh (i.e hydrolysis constant) and Kh = Kw/Ka. And from here we calculate x and then [H3O+] = x. And then pH = - log (x).
i know this is old but another way to get [H3O+] is using:
[OH-][H3O+] = Kw
so,
[H3O+] = Kw/[OH-]
Kw is constant: 1.01 x 10^-14
now u can use the -log[H+]
best explanation
gless u man saved my grade
OK I'm sorry. I was wrong Kh
= Kw/Ka is in case of hydrolysis of salt. Thanks. For video
Do we have to always assume that x is a very small number?
Only a very small amount of a weak acid/base dissociates.
If initial concentration/ka >100 then we can ignore x
Thank you so much sir! I 🥹🥹
Thx! Much help
Thanks!
thank you
thanks...
thank for sharing
Why is the volume so low?
go to a doctor
Or become one
ughhh i agree... its getting on my nerves
it's good for me dude. bruh
good
What if Ka and Kb are not given? How would we find the pH buffer?
thank youuuuuuuuuuuuuuuuuuuuuuuuuuu
whose watching after 6years
Why is this not a buffer system ? why didn't we take the -log of the Ka and then the log of the ratio of conjugate base over acid?
that works too. For example the second problem whose PH was 8.89. You could have use kw/kb to find Ka and then the solution is simply PH = -log(5.56 x 10^10) + log (0.15/0.35) will give you the 8.89 PH he found without having to go through all of those steps . It is good to know the ICE method solution however
not me abusing the Henderson-Hasselbalch equation to get the same answers
You cannot use a calculator on the MCAT. You should show people how to best approximate these values. Example: -log(m x 10^-n) = approx. n - 0.m. So for this video -log (7.7 x 10^ -6) = 6- 0.77 = 5.23
Can u explain this elaboratly
Arrigato
why is the x small??
Please fix the sound
What does happen to Nh4NO3??
it makes the concentration of NH4 increase, this is all happing at once
All your videos are calculate pH, the EASIEST. Why not do an example on calculate strong base conc. if the pH of acetic acid buffer is _____________.
Why is the volume always so low in khanacademy videos?
HKUST anyone?
Plz also translate ur lectures into urdu...........
advance thanks :-)
These videos are meant for MCAT preparation, an exam tested in English. Go look for videos in your language else.
These are AAMC approved videos and given that use of calculator is not permitted in the exam, is it the time you showed your viewers how to solve these problems WITHOUT a calculator?
Marry me professor
chemistry sucks but thx for the video anyway
If ye then be risen with Christ, seek those things which are above, where Christ sitteth on the right hand of God. Set your affection on things above, not on things on the earth. For ye are dead, and your life is hid with Christ in God. When Christ, who is our life, shall appear, then shall ye also appear with him in glory. Mortify therefore your members which are upon the earth; fornication, uncleanness, inordinate affection, evil concupiscence, and covetousness, which is idolatry: For which things' sake the wrath of God cometh on the children of disobedience: In the which ye also walked some time, when ye lived in them. But now ye also put off all these; anger, wrath, malice, blasphemy, filthy communication out of your mouth. Lie not one to another, seeing that ye have put off the old man with his deeds; And have put on the new man, which is renewed in knowledge after the image of him that created him: Where there is neither Greek nor Jew, circumcision nor uncircumcision, Barbarian, Scythian, bond nor free: but Christ is all, and in all. Put on therefore, as the elect of God, holy and beloved, bowels of mercies, kindness, humbleness of mind, meekness, longsuffering; Forbearing one another, and forgiving one another, if any man have a quarrel against any: even as Christ forgave you, so also do ye. And above all these things put on charity, which is the bond of perfectness. And let the peace of God rule in your hearts, to the which also ye are called in one body; and be ye thankful. Let the word of Christ dwell in you richly in all wisdom; teaching and admonishing one another in psalms and hymns and spiritual songs, singing with grace in your hearts to the Lord. And whatsoever ye do in word or deed, do all in the name of the Lord Jesus, giving thanks to God and the Father by him. Wives, submit yourselves unto your own husbands, as it is fit in the Lord. Husbands, love your wives, and be not bitter against them. Children, obey your parents in all things: for this is well pleasing unto the Lord. Fathers, provoke not your children to anger, lest they be discouraged. Servants, obey in all things your masters according to the flesh; not with eyeservice, as menpleasers; but in singleness of heart, fearing God: And whatsoever ye do, do it heartily, as to the Lord, and not unto men; Knowing that of the Lord ye shall receive the reward of the inheritance: for ye serve the Lord Christ. But he that doeth wrong shall receive for the wrong which he hath done: and there is no respect of persons.
Colossians 3 KJV
bible.com/bible/1/col.3.0.KJV
Am i the only one who dint get this lecture??
There are a lot of terms that you have to learn before watching this video. Maybe you are confused because you don't know the definition of some of the terms (le Chatlier's principle, equilibrium, shift, etc.)
how can pH be greater than 7???
+Parth Ranawat pH is a measure of how acidic/basic water is. The range goes from 0 - 14, with 7 being neutral. pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base. Got this from google.
Wtf??
Of cause, otherwise why do we have pH up to 14?
rubbish
Thank you so so so muchhh , I have my chemistry exam tomorrow ( 6 units included ) & you're being a lifesaver rn. 🤍
Thank you so much