Molecular and Empirical Forumlas from Percent Composition

[belenysanti]

Thank you thank you thank you!! You have no idea how grateful I am for all this videos.

[MrEpicMunch]

Me gusta. :3

[TheAvarockz]

omg! i love you!! you made it so much easier for my chem quiz! <3 <3

[SaleishaC]

wow it was so cool when u dragged the calculator out hahaaa lol:D

[MsAsmaa95]

Khan, you literally saved me from failing my chemistry test thank you :D

[aznpride0]

omg I did the problem before I watch how you solve it. When I see you write down oxygen have 6 instead of 2 I feel so sad. Luckily you fix lol i though i got it wrong

[galencheng7]

You spelled formula wrong on the title.

[1c34l1f3]

Where do you get that calculator!!

[ajmack007]

Wow, that makes, sense, why can't my chemistry teacher teach it that way, wait they don't, and the book explanation is very confusing! Thanks so much!!!

[superjellboy]

dude you teach this stuff way better than my chem teacher

[iSh0uldBeStudying]

I know u hear this all the time but I'm going to say it anyway. U R AN AWESOME TEACHER, I'm really glad I found your videos.

[AJ286100]

my teacher made a stoich song lol : you go from mass to mole, you go from mole to mole, you go from mole to mass and you shake it all around, you do the stoichi oichi and you mix it all around, thats wat its all about lol !!!

[SuperZootman]

@AJ286100 That's the gayest shit I've ever heard.

[AJ286100]

@SuperZootman i know lol

[Seguris]

Hahaha Sal! It's the fist time I've seen you using Shortcuts for Undoing XD Thanks a lot for the video.

[badadelgbrian]

@ 6:30 he used atomic weight and atomic mass.. It should be

Atomic mass: the average mass # of all isotopes of an element. --- and

Mass number: is the specific mass #

weight is wrong because it is capable of changing therefore not consistent.... BUT

Mass is always the same here or in any planet.

[DarkShadowMegadeth]

Forumlas lol

[frengiman]

thanks



[3333sweetie]

u accidentally wrote 6 instead of 2

[Saher4321]

Sal I think this was your most confusing video for me I guess maybe cos over here we don't really work with a percentage as we diving the smallest mol out of all of them and thus get the ratio! Nevertheless your videos are awesome can you please do more advanced chem like uni stuff like Pauli exclusion principle, hunds law, converting frequencies to wavelengths and the list could go on and on but if u can do these 3 it'll help so much mate!xxx

[Saher4321]

Sal I think this was your most confusing video for me I guess maybe cos over here we don't really work with a percentage and we diving the smallest mol out of all of them and thus get the ratio! Nevertheless your videos are awesome can you please do more advanced chem like uni stuff cos tll help me and so many other people!!!!! Xxx

[nekuritte]

I think the problem is not stated well enough. You assume that the concentrations of C and H are concentrations by mass, although these may also be concentrations by volume or by molar weight.

[MeaganMango]

What the heck?! Where did you get .0737, and .7314??? That's confusing and it just lost me there after I paused it??

[jkingiv]

@MeaganMango ... 7.37% H is the same as the decimal equivalent of .0737, and the 73.14% C has the decimal equivalent of .7314. We have to use the decimal equivalents to multiply with the number.

[sixohhtwo]

@MeaganMango He made the percentages into decimals; it's basic math and makes it easier to understand what the calculator shoots back. Say you have 75% of 1 whole. That would be 1.00 = whole. %75 is a piece of this whole. 75% of 1.00 is .75. Think money. That's basically what he was doing. He was finding the percentages of 164.2 grams. To do that you multiple the whole (in this case 164.2) by the percent (73.14% = .7314) to get 73.14% of his total. 73.14% of 164.2 = 120.1. Hope that helps.

[hasijaz93]

Where did you get that calculator from ?

[WannabeRich93]

Cant you do empirical formula with percentages (for as level it makes a difference)?

[Moviemann345]

You accidently wrote 6 instead of 2 lol

[paulceltics]

@Moviemann345 goes to show harvard guys do make mistkaes

[AJ286100]

@Moviemann345 who feals as if they are the smart ones in there class now !

[aboodal3las]

@Moviemann345 yeah man he made me pause the video for 10 minutes to figure out why !! LOOOOL

[xxladybug94]

wait why does Oxygen have 6 moles instead of 2??

[jbeddiejb]

Thank you very much, Mr. Khan. I am just starting 12th grade in an Irish highschool and already covered most of these topics, but your videos and helping me to revise alot and truly you would be a much better teacher than my current one. If you gave private online lessons I bet many people would pay to be tutored by you.

[vart12345]

Buen Maestro, gracias KHAN.

[spincycle62]

You need to consult with the spelling academy when putting the titles in your videos -- "emperical" :-)

[ash9023]

@spincycle62 he is right

[MafferDragonhandEyed]

mol stands for molecule?

[Ruthlessvalor]

@MafferDragonhandEyed Mol = Mole.

Molecules are written as molecules.

[EzratheDog]

@MafferDragonhandEyed

mol is another way of saying you have 6.022x10^23 molecules of a substance

[75zk]

@EzratheDog

that is the vacadro's constant

[EzratheDog]

@75zk

*Avogadro

[biozamadotcom]

You could do problems like this every other vid

and I'd be totally grateful.

[MomoBG2]

yea funny confusement with the atomic number of C :))

[bakeee]

khan, thank you so much. i hope you continue with these videos

[MomoBG2]

at mind 9:00 its 2 molecules of O not 6

[zackboomer]

@MomoBG2 he even said 2 as he wrote 6 lol