this helps me a lot in studying to face my stereochemistry exam tomorrow, thank you!

I wish i had found your channel earlier...i have been struggling with analytical chemistry...you literally made this topic simple...thank you

@Leah4sci

2 жыл бұрын

You're so welcome! I'm glad you found my channel now and can help you moving forward!

LEAH IN 9:45 CHECK U USED CONCENTRATION IN MOLARITY BUT IT SHD BE GRAMS/ML. BUT THE EXPLANATION WAS SAVAGE .

@Leah4sci

7 ай бұрын

Yeah... KZread doesn't allow me to edit a published video :( I'm glad you recognized the mistake and understood the rest regardless

Wow this was the most simplified breakdown I've seen! Thank you!

@Leah4sci

3 жыл бұрын

You're so welcome!

AMAZING! Thank you for the slow and well explained breakdown. It was very informative! Thanks again

@Leah4sci

3 жыл бұрын

Glad it was helpful!

Thank you so much... Due to Covid-19, my university is conducting online lessons which aren't working so well for me. Thanks to you, I'm able to understand these topics as if it were a physical class

@Leah4sci

3 жыл бұрын

You are most welcome, I'm so happy to help, especially now while everything has changed so dramatically.

There is a mistake with the calculation part. I solved it taking concentration in g/ml (since we know the molecular weight of butanol we can easily calculate that) and path length as 10 cm and I got the specific rotation as -13.51 which is same as the value given in the question for specific rotation. This means that the sample is enantiomerically pure. Honestly, I was pretty impressed by your video untill I saw this blunder. Love the way u explain things in your video.

@joypalit6408

3 жыл бұрын

i think you made a mistake in the calculation part. the ans comes out to be 135.1 degree

@Leah4sci

7 ай бұрын

Yes, there is a mistake on the video. KZread won't allow me to edit once it's posted and so I hope to re-record and post a new one explaining this correctly

Thanks a lot madam, that was the best explanation i had, that too with a problem , a solution and in around 10 minutes I am going to write world's second toughest entrance test this month, and your video is gonna help me a lot.

@Leah4sci

2 ай бұрын

You are very welcome, I'm so glad this helped you! Best wishes on your entrance test!

Taught myself this since I gotta record a video for class on the homework we have and i didn’t want to do the ones that everyone else was doing. Thank you so much this helped a lot!

@Leah4sci

2 жыл бұрын

You're very welcome!

Take respect mam 😊 You voice to too good to understand for someone for whom english is his 2nd language. From Bangladesh 🇧🇩

@Leah4sci

Жыл бұрын

So glad to hear it! Thanks for watching. :)

Really love your videos. Thats why i would be so Happy If you could do some carbonyl mechanism videos.

@Leah4sci

6 жыл бұрын

Thank you! which specific mechanisms? I won't be uploading anything orgo 2 for the remainder of this year but I do cover carbonyls in depth in the study hall including last night's workshop. Details: leah4sci.com/join

You're really helpful. Thanks Leah

@Leah4sci

4 жыл бұрын

Glad I could help!

great videos, Thank you! where is the next video you referred to at the end of this one?

@Leah4sci

5 жыл бұрын

You're welcome! Thanks for dropping by! Please subscribe to keep posted of the new videos uploaded

Hello! Thanks for this video! I have some questions regarding 6:15 Wasn't it said in the introduction to optical activity video that + and - rotation does not equivalent having a R and S enantiomer respectively? (e.g. if rotation is (-), enantiomer is R). How did we immediately determine that the levoratory rotation is caused by the R-enantiomer and vice versa? Thank you!

@felicitaschukwude5814

2 жыл бұрын

Good question

@Leah4sci

2 жыл бұрын

Yes, you are correct. I did say that, and it still holds true. All I was trying to say in this segment of the video was that the R and S enantiomers must spin light in different directions. If the one is negative, then the other must be positive. And vice versa. It depends on the specific molecule you're looking at.

Preparing for the competitive exams.... Thanks!! ❤

@Leah4sci

Жыл бұрын

You're welcome!

Hello, Could you explain to my why 4) the wavelenght affects the observed rotation? I mean what is the difference between the wavelegthn and what impact do they have?

@Leah4sci

4 жыл бұрын

For most of these problems you’ll see a constant wavelength so not something to be worried about. However consider this: If optical rotation is LIGHT hitting a molecule to turn it, then having more/less light hitting it will impact rotation. Wavelength is a measure of the lightwaves in this situation.

Can you please explain the effect of the solvent on the Optical rotation and the selection of sodium

@Leah4sci

5 жыл бұрын

I'm sorry, but I don't offer tutoring through KZread comments. For help with this topic and more, I recommend joining the orgo study hall. Full details: leah4sci.com/join

I think there is a mistake on the example calculation. The concentration of the solution was given in molarity whereas the required units for concentration for the specific rotation calculation are "g/mL".

@Leah4sci

5 жыл бұрын

At which point of the video please?

@daniela.nichols2012

5 жыл бұрын

@@Leah4sci 11:16

@brandoncarmen4738

4 жыл бұрын

@@Leah4sci Is there confirmed an error/explanation if it was correct?

@KaroAss66

4 жыл бұрын

@@Leah4sci Please look at 9:45. You can not use the concentration in molarity. You need to calculate the concentration in g/100mL first and put that in.

@rohailalam72

4 жыл бұрын

@@KaroAss66 The unit of concentration is moles/unit volume, she made a slight blunder there by writing "gm/cm3" . The reason why she used molarity as it is is because the unit of molarity is the same as concentration, i.e moles/unit volume.

Thanks for the tutorials

@Leah4sci

6 жыл бұрын

You're welcome!

Thank you so much 🥰 madam,I have understood everything just on easy ♥️

@Leah4sci

Жыл бұрын

Glad to hear that! You're so welcome.

Do you not have to use the concentration in g/mL when you do the calculations?

@Leah4sci

6 жыл бұрын

At which point in the video?

@Sal19

6 жыл бұрын

Leah4sci You used the concentration in units of molarity (mol/L) When you should have changed it to (g/L).

@earnfuntv3952

4 жыл бұрын

@@Leah4sciat 9:45 min mam

@earnfuntv3952

4 жыл бұрын

@@Leah4sci thanks very helpful for medical entrance exam

@yarakitty2738

3 жыл бұрын

I have the same question

Thanks for wonderful explanation❤❤

@Leah4sci

4 жыл бұрын

You're welcome 😊

Can you go over how to do optical activity percent composition questions like this? What is the percent composition of a mixture of (S)-(+)-2-butanol,[] = +13.52º, and (R)-(-)-2-butanol,[] = -13.52º, with a specific rotation [] = +6.76º? Answer is 25%(R), 75% (S). My professor wanted us to know these and she never went over it. I don't think there's an easy formula for it either.

@Leah4sci

6 жыл бұрын

That's video 3 in this series already posted on my channel. Let me know if you can't find it

Thanks for the explanation

@Leah4sci

4 жыл бұрын

You're very welcome!

Can we differ eantiomer by optical activity

@Leah4sci

5 жыл бұрын

differ do you mean separate?

hi Leah in your playlist the order of the part 2 and part 3 are swapped. the part3 is before the part 2. also I wanna thank u cuz your videos are amazing!!! you're such a good teacher

@klausconteschertel2353

2 жыл бұрын

I sent your playlist to ALL my classmates lol. but I unfortunately don't think they checked it

@Leah4sci

2 жыл бұрын

Thank you so much!! I went ahead and switched the order of the videos you mentioned. Glad you're enjoying and learning with my videos. :)

1st of all thanks for the awsome explanation! Secondly, if I want to calculate the conc of each enantiomer induvijually, can I assume (let's say) x moles of R enantiomer and ( .25 -x) of S(same eg from your vid) then I find this conc in gm/ml( by multiplying atomic weights ,Dividing by 1000 and multipling by 13.52 with their signs in each case ) and multiply it by specific rotation for both x and .25-x and then subtract them (R-s) to get a net -ve optical rotation and equate it to -2.5 to get x. I don't know if optical rotation(observed) alpha follows algebraic laws (of add or subtrac.) So if you can please check this if it's valid method or not thankyou!!!

@Leah4sci

3 жыл бұрын

So glad you liked it! Regarding your question, I'm sorry, but I don't offer tutoring over social media . For help with questions like this and more, I recommend joining the organic chemistry study hall. Details: leah4sci.com/join or contact me through my website leah4sci.com/contact/

Hey still problem with the C value, it should be g/ml at min 11 you give examples and use 0.25M as C which is wrong. txs

@Leah4sci

4 жыл бұрын

Thanks for pointing this out!

Does tube lengths affect specific rotation or optical rotation

@Leah4sci

8 ай бұрын

Specific rotation is 'specific' thus a standardized value regardless of tube length.

At 9:52 why you took molarity instead of in g/ml....

@Leah4sci

4 жыл бұрын

Di, tri, tetra… don’t count when analyzing alphabetical order

It is contradictory and misleading that you explained "c" as concentration in g/mL, but then use mol/L as "c" for calculation in the later part of this video. Since they are obviously quite different. If you convert M, which is mol/L, to g/mL like it should have been: 2-butanol's molar mass = 74 g/mol --> (0.25 mol/L)(74 g/mol)(1/1000 L/mL) = 0.0185 g/mL = c --> [a] = a/c*l = -2.5/(0.0185 g/mL)(1 dm) = -135 --> a = [a]*c*l = -13.52(0.0185 g/mL)(1 dm) = -0.25 In conclusion, since my answers for [a] and a are only different by the factor of 10, there must be some error made when you were writing down this question. Please clarify this for us, Leah. Thanks!

@Ara2061

5 жыл бұрын

yes I have the same question !!!

@zipskoy7210

4 жыл бұрын

Got the same answer as u, thanks.

@Leah4sci

5 ай бұрын

I messed up in the recording, I plan to redo this video at some point. I apologize for the confusion

Wow amazing

@Leah4sci

2 жыл бұрын

Glad you liked it

interesting that the specific rotation decreases at higher temps. I would think that if there is more energy, then the light is colliding with more molecules, and thus rotating more?

@Leah4sci

Жыл бұрын

That's a great hypothesis! It would be interesting to test it. However, I believe that the effect of temperature on specific rotation depends on the compound being studied.

How come -2.5 is less than -3.38? I think u mean since -2.5 is more than -3.38 then that is why there is some S remaining right?

@Leah4sci

2 жыл бұрын

I understand the confusion in that -2.5 is actually a larger number when placed on a number line. However, the negative sign here simply refers to the direction in which the enantiomer turns light. It is not meant to affect the numerical quantity, if that makes sense. So instead, think of it as: a 2.5 rotation is less than a 3.38 rotation.

thanks mam

@Leah4sci

6 жыл бұрын

You're very welcome!

thnks mam,

@Leah4sci

6 жыл бұрын

You're very welcome

Why would you write specific rotation inversely proportional to concentration..... Why it not be directly proportional to specific rotation ?????.....because as you told more the conc. Of chiral molecule more will be the rotation.... So thus it must be directly proportional but it not.... Why it so ?????

@Leah4sci

5 жыл бұрын

At which part of the video please?

@earnfuntv3952

4 жыл бұрын

Yes rotation is directly proportional to concentration not specific rotation

superb 💪👌

@Leah4sci

2 жыл бұрын

Thank you so much 😀

calculation in the example is wrong, C is g/ml and not in Molar !!

@Leah4sci

5 жыл бұрын

Thanks for letting me know. At which specific point in the video? (timestamp please)

Real

@Leah4sci

9 ай бұрын

awesome

Very hard

@Leah4sci

3 жыл бұрын

Sorry to hear that you have problems with this. Check out my website for more resources: leah4sci.com