How to Calculate Molarity | Practice Problem #1 | Solution Chemistry | Chemistry | Whitwell High School | UTC - University of Tennessee at Chattanooga www.whitwellhigh.com Instructor/Professor: Johnny Cantrell
sir, your lecture was so increadibly coordiniated and simple that i completley understood everything word of it and i just want to say thanks, youre very good at teaching this and you really did save my highschool/military carrer, im on the verge of a dishonorable discharge and this really made things a lot easier for me to accomplish
I did this on my calculator and I got a totally different answer without using parenthesis. I am putting this out so people know to use parenthesis when doing this calculation.
Awesome, I'm so glad you are breaking the info down and do so in all your Vids. Thanks so much for making a difference and taking the anxiety out of learning chem!
why in hell did i not go to youtube first for chemistry clarification? I would have if i knew it was SOO much more helpful than my chem teacher! Thanks!
thank you so much whitwellhigh..we got this as a pre lab assignment.. we had to teach this to ourselves (without lecture) in order to get it turned in before lab :(
@3333sweetie - yes you may do that if your professor allows you to....some are picky and it must be done their way.....0.5 (12.0gC/1moleC) is correct simply because the units line up in dimensional analysis.......however....I strongly suggest sticking with dimensional analysis for its flow of units and cancelation properties :).......you could do your method here so long as you remember to divide your number of moles by liters of solution.
Nicely done. I find that using #moles= molecular weight / molar weight -- followed by M=#moles / L is much easier. It leads to less confusion and errors. But nicely done!
No...it is correct....if you look....I converted to mL to L so 250.0mL became 0.2500L.....but remember....if you have a divisor such as 0.25...it is the same as multipling by 4 in the numerator......or....multipling the other denominators by 0.25 :).................but I only have 0.25L in the denominator. If you do not like the extra conversion step in the problem...convert it to L before placing it into the work.
@EmilyHorneswaggle - you are correct emily...that is another name for it....I refer to it as concentration myself....but for a particular set of homework problems in my students book, they referred to it as molarity (which is correct) so that is what I put in the title...Maybe I should have added the words molar concentration and concentration to the description lol
@3333sweetie - well....if you mean by percent composition....then...i guess you could....in my eyes...appears to be to much work.....it is easier to just use dimensional analysis to work the problem...that is my choice....however, there is always more than one way to work a problem.....it is just....i used my favorite way to work the problem :)
@JulioMaestro116 - :)...thank you....but i can not take all the credit....when I was really young....that is what we did (just go ahead and convert the mL to L).....but as I advanced in my years of teaching.....It made more sense to use dimensional analysis to solve/convert the units desired.
Praise: Very helpful thank you! I really appreciated your pace and the explanations you put behind your next step. Very nice. ^___^ Critique: I have nothing bad to say, but I would suggest that you annunciate your words. I tried to turn on closed captions and it was quite humorous how some of the interpretations came to be. Over all, very nice video - keep up the good work, thank you!
@diegoelopez ikr. My chem teacher writes an example on the board, with no explanation, and assumes we understand exactly what he just did. He doesn't explain anything. I am so confused in chem, and it has made me hate the subject more than any other subject I've ever taken. I wish I had a good teacher from the start. Maybe then I wouldn't hate it so much.
@whitwellhigh no, i mean like let's say they ask how many grams are in 0.5 mole C? I do it like this: 1 mole Carbon=12grams Carbon, let X=new mass of carbonand u multiply 0.5 by 12g to get 6 grams, theanswer. can u do that?also, where can i find a cd or place where they have interactive lessons(like yours on chemistry topics)?
Great video! However, you like my chemistry teacher over explain it and make it seem harder than it really is/should be (atleast in my oppinion). I do this instead: (1.461/(22.99+35.45)) to get the moles of NaCl, which is 0.025 Then I divide that by .250 liters. So 0.025/0.25 = 0.100
I think that the answer is actually .1008M because the way you did it says that we 4 L of water instead of .25L. Maybe I am confused so someone please correct me if i am wrong.
when ever they given you grams or mention grams in a problem...you gonna always have to calculate the molar mass....which is always one mole. :) Did that help?
sir may answer is 0.1M its that acceptable? i get the mole 1st 0.025 then convert the 250ml in L i get 0.25 then 0.025mol divide 0.25 i get 0.1M. its that ok?
jeshurun yu same here the reason why you get .025 as the Mol is because you're dividing 1.461/ 58.44. The problem says that MM of NACL is 58.443. That extra 3 at the end makes all the difference in why you're getting .1.My issue is when calculating the Molar mass I get 58.44 and not 58.443 which I have got noo clue as to why the problem has that extra 3 on the end.
