Thank you so much Dave sir, I couldn't understand this concept in my teacher's 1.5 hour lecture which I understood here with crystal clarity here in 4 minutes!! You have excellent teaching skills, I am a fan of your videos sir !!

Hello, Prof. Dave. I'm a science teacher at a high school in Tokyo. So I enjoy watching and learning your movies. I'm currently teaching organic chemistry, hydrocarbon first of all. I hope we can exchange some topics, or info. The thing is I did the lecture about this topic the other day. So I noticed the turn of the absorption of water and CO2 was different. They're usually removed, absorbed with CaCl2, and soda lime. The latter can absorb both ones, so water should be removed first of all. Of course your lecture has no problem in itself. Thank you.

Good idea "check comprehension“ Physics videos so oftenly make u believe you get it... But not

It can be like C = 1.2g = 0.1 mol H = 1.45-1.2 = 0.25 = 0.25 mol C : H = 0.1 : 0.25 = 2 : 5

Prof. Dave you are my hero!

Explained 1/3 of a chapter in ~4 minutes which took my teacher to teach 4 weeks, LOL! Thank you Professor Dave

Hello Professor! I am so grateful for your videos. Content like this can have a big impact on society as the more students ***understand*** the basis of science, the more likely we are to reach further! I have a question as well, on min 2:40 you gave the molecular mass of benzene (78 a.m.u.) in order to get its molecular formula. My question is, how could one know the molecular mass without having the molecular formula first? that way seems to make more sense to me. Was it discovered with experiments as interesting as the one to discover the percent composition of benzene? The second question was whether the quotient of the molecular masses of the molecular and empiric formulas was always a whole number. It seems it will always be but, is there any instance it would not? can we say that when it is not a whole number, we have done something wrong? Thank you again and again!

That is superb Prof. If i keep on watching your videos i will never be the same again. God bless you

How did you get a ratio of 2:5 = 6.9:17.1??? I'm really confused. I need to pass my exam. T_T Thank you in advance Prof. Dave! ^_^

At the end of the day you really have to know amu's to make any of this work.

Great videos! My chemistry days are well in the past but one thing that confused me... when specifying grams per mole why do you use whole number amu/s of 16 and 12 for O and C, but 1.008 for H. I must have missed something.

Nice to meet you again proffesor dave Nice video

Prof. Dave, how do you know a molecular mass of an unknown sample? If you don't know empirical/molecular formula in the first place (as we need to do combustion experiment to find one). Thank you so much in advance!

what if we have an inorganic Compound such as layered double hydroxide which has hydrocarbon inside. then, what happens to that inorganic compounds hydrogens. are they counted in the resulting percentages? tnx for your awesome channel.

Hi dave, I son't understand why you burned 0.342 g. I also don't understand why you took 1.156 g of carbon dioxide. Can you please explain it to me?

First let me say these videos are great, thank you for making them. I was just thinking though that the example for a molecular formula was a bit redundant in the sense that you need to know the molecular mass of the molecule to calculate its molecular formula. But to know the molecular mass, you must know the molecular formula to know how many times you multiply the atomic mass of the individual elements. So do you have another example that doesn't imply that we just know a molecule's molecular mass?

I would like to know iw the general chemistry order playslist as the mathematics one ? ( Meaning it's going from 0 to 1000 ) ? Because I have a more hard time to understand the general chemistry one , there is so many things that we do not know but that are already appearing here . Exemple at 0:31 when professor daves talk about combustion but by learning chemistry only from this playlist we dont know what is it yet !

This lecture removed my confusion....

At 3:15 in the top left, why did he multiply by 12.0g C/44.0g CO2? I thought the denominator and the nominator should be equal.

wouldn't the ratio be 1:3 in the comprehension question? since 17.1/6.9=2.47=2.5=3 for hydrogen ? rounding up to 3? and 6.9/6.9=1 for carbon?

If C is 6.9 and H is 17.1 then wouldn't the ratio be C5H2 instead of C2H5? since 6.9 is multiplied by 5 and 17.1 is multiplied by 2.

Huge love n appreciation from India

Thank you very much

Why are the percentages used to calculate the empirical formula and not the actual weight, as usual, to determine the moles?

What's the name of the method of separating carbon dioxide and water when hydrocarbons were burned?

So I assume this is the old way of doing like Mass spectroscopy or I guess the precursor to it?

How can we count that there are x numbers of protons neutrons and electrons then we can't see atom it self ?

Hi Professor Dave! I was wondering how experiments like this can get a accurate answer on the chemical composition of something by reacting it with something and measuring the products since the expected yield and the actual yields are pretty much never 100% accurate.

But how do you get the molecular mass in the first place without knowing the actual number of each element in a molecule?

Good

where did on the check comprehension for 6.90:17.1 = 2:5 come from? i just cant see it.

dear professor Dave, I didn't understand why we are assuming we have 100g of benzine when we find the ratios of both carbon and hydrogen knowing that we were already given a specific mass at the beginning of that substance?

Professor Dave, do you know when you round off your values as I get the percent rounding wrong

Hello sir nice lesson but in the "Checking Comprehension" I didn't understand on where you get the 2:5 ratio, please help thanks :)

Just out of curiosity, would combustion only form CO2 and H2O? What if H2O2 or some other product was produced?

‏‪0:52‬‏ الرسم

Why is 12 amu being divided by 44 amu, why not subtracted?

how did u find the ratio?

But how we can calculate the molecular mass if we don't know the molecular formula yet ?!

1:02 just a bookmark

Sir we want to do extraction of ALKALOIDS TANNIN CAFFEINE ETC please make a video on extraction 🙏🙏❤️

How in the ... do you weight hydrogen?

why is this the first video that had me confused T.T

I don’t get it one bit, perhaps,take it slow

HUH?M WHAT😭

...st the end during checking comprehention, can someone PLEASE explain to me how 6.90:17.1 = 2:5 ??? ...and how to calculate it manually ? tY