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Jeff Orvis
เข้าร่วมเมื่อ 10 เม.ย. 2014
I love talking about chemistry, especially NMR spectroscopy. I love exploring NMR, studying NMR, and telling others about NMR. I'm one of those people for whom the phrase "doublet of triplets" gets my heart racing just a little bit faster. After all these years, I still marvel at how powerful NMR spectroscopy is at telling us about molecules. I hope to share a bit of that, and other parts of chemistry I find so much fun. I hope you find something interesting and helpful.
Inflating a Balloon Two Ways
Most people inflate a balloon by increasing the number of moles of gas inside the balloon. I, of course, am not most people ...
มุมมอง: 78
วีดีโอ
Demonstration: Stoichiometry and Percent Yield
มุมมอง 47ปีที่แล้ว
We're making salt the way grandma used to make it, and then finding out if I did a good job of it or not by calculating the percent yield.
Counting Smarties by Weighing Demo
มุมมอง 883 ปีที่แล้ว
In chemistry we never actually physically count stuff ... we count things by first chucking them on a balance. Here's a demonstration of the process using Smarties, candies we can both weigh and count.
Hot vs Cold Water Density Demo
มุมมอง 783 ปีที่แล้ว
A classic demo of the differences in the density of hot vs cold water.
The Methane Bubbles Demo
มุมมอง 6K3 ปีที่แล้ว
A quick look at the classic methane bubble demo. I usually do this on the first day of general chemistry. This year, of course, everything is different ... so I recorded it as a video instead.
Back to School: Finding a Classroom in Fall 2020
มุมมอง 844 ปีที่แล้ว
As the Fall Semester approaches here in 2020, things are going to be different at college. Like, finding a classroom ...
Methylene Groups and Chiral Centers
มุมมอง 914 ปีที่แล้ว
Methylene Groups in proton NMR ... they should be so simple, and sometimes they are. And sometimes, they are just so prone to overlap problems: th-cam.com/video/oEWddeY_rZQ/w-d-xo.html And sometimes, if they show up at the end of an alkene, lack of free rotation can complicate them in a spectrum: th-cam.com/video/NDii3dYQoKc/w-d-xo.html And then you can run into simple molecules with a chiral c...
Drawing Coupling Trees to Understand Multiple Coupling Patterns
มุมมอง 3304 ปีที่แล้ว
Multiple NMR coupling patterns likes triplets of doublets and doublets of triplets are often challenging to understand. Actually getting out some lined paper and drawing coupling trees are the most effective way to quickly understand how these patterns work. Here's a demonstration on how its done.
Methylene Groups: Untangling Terminal Alkenes
มุมมอง 1035 ปีที่แล้ว
The methylene group can be a problem in interpreting NMR spectra. They are often overlapped, and the two protons can have quite different chemical shifts under certain circumstances. A classic example is the methylene group at the end of a double bond: the terminal alkene. We'll see three examples, and look at the techniques available to help untangle these resonances. A pdf document of all the...
A Deep Dive into a Doublet of Doublet of Triplets
มุมมอง 3.7K5 ปีที่แล้ว
Proton NMR coupling patterns involving several coupling consants can be absolutely beautiful to look at. Here we take a deep dive into the doublet of doublet of triplets observed in the spectrum of pentene, and look carefully at how we extract out the coupling constants. Here's a link to a pdf of the spectra shown in the video: drive.google.com/file/d/1ZfPSdrpKKjZ-I1dHZNFlnWpHUgzEygfF/view?usp=...
Groups and Integrations Student Question
มุมมอง 905 ปีที่แล้ว
Groups and Integrations Student Question
Using NMR Spectroscopy: Methylene Groups and Signal Overlap
มุมมอง 2165 ปีที่แล้ว
Methylene groups, CH2's, can often be quite troublesome in proton NMR spectra. Often, they look distorted, messy, complex ... certainly not as straightforward as textbooks would like. We'll look at a number of reasons for this in a series of videos. This one looks at a very common problem in proton NMR: signal overlap. It will also show how carbon and HSQC spectra can really help in fully under...
Using NMR: Always Check Your Starting Materials
มุมมอง 845 ปีที่แล้ว
Structure determination is the classic example of the use of NMR spectroscopy. A much more routine use that is just as important is the routine check of starting materials. Before you start a long synthesis project, you should really be sure the label on the bottle is right. Here's a pdf of the spectra shown: drive.google.com/file/d/1C83k8Z2v-UrB4JcZuaZbvSjUrwJcEjTV/view?usp=sharing
Teaching NMR: Mapping out an Unknown with 2D NMR Spectra
มุมมอง 2826 ปีที่แล้ว
Teaching NMR: Mapping out an Unknown with 2D NMR Spectra
An Ibuprofen NMR Mystery Solved by DEPT Spectra
มุมมอง 3706 ปีที่แล้ว
An Ibuprofen NMR Mystery Solved by DEPT Spectra
Interpreting NMR a Given Molecular Weight
มุมมอง 2166 ปีที่แล้ว
Interpreting NMR a Given Molecular Weight
Interpreting NMR Unknowns with Groups and Integrations
มุมมอง 1846 ปีที่แล้ว
Interpreting NMR Unknowns with Groups and Integrations
Activation Energy: Arrhenius Two Point Example
มุมมอง 1756 ปีที่แล้ว
Activation Energy: Arrhenius Two Point Example
A Standard Stoichiometry Problem Example
มุมมอง 676 ปีที่แล้ว
A Standard Stoichiometry Problem Example
Interpreting NMR: Best Friends and Spectra Matching Examples
มุมมอง 2086 ปีที่แล้ว
Interpreting NMR: Best Friends and Spectra Matching Examples
Interpreting NMR: Best Friends and Structure Line-ups
มุมมอง 2106 ปีที่แล้ว
Interpreting NMR: Best Friends and Structure Line-ups
Dr O's Guide to Gas Mixtures and Partial Pressures
มุมมอง 796 ปีที่แล้ว
Dr O's Guide to Gas Mixtures and Partial Pressures
This is the best description of HNMR I've found on youtube. thank you
this is super helpful, thank you
do you have a screen in front of the camera? How do you get the awesome glowing pen?
What is the hardvard of the south?
this is so helpful thank you
Ha! Seasoned teacher, you make this look so smooth, writing from your right to left, and backwards/inverse! Nice work!
Think you😅
At long last
Well done, Jeff. This was well presented!
Hi Jeff, great explanation. Only 400 MHz, is 400 million Hertz (rather than 400 billion Hertz). Keep up the good work!
awesome! best video I've found on lock & shim
Great explanation, thank you
Thank you for an Informative Video🙏👍 Could you guide me with:- Which positions of the magnets will be most efficient and what design to consider to build a prototype for Magnetic Separation of isotopes Dy(III)? Thanks
Good job, Jeff! your student really is soo lucky for owing a prof like you:)
Hi. Please I am wondering how long does it take to acquire a spectra from a sample on standard NMR machines?
The answer is ... it depends. A standard proton spectrum of a reasonably concentrated sample can be acquired in under a minute. A highly dilute sample that requires over 100 scans can take five minutes. If one were to do a whole suite of experiments on a sample (proton, carbon, DEPT, COSY and so on) at least an hour of time is usually required. The longest experiments we typically see are carbon spectra of samples that have a low solubility in any common deuterated solvent. Those can be overnight runs of thousands of scans to get well defined peaks and a reasonable signal to noise ratio. I hope this helps.
Thank you
Really cannot thank you enough for this explanation sir. Bless you
Thank you sir.
Great explanation sir. Thank You.
Thank you so much, it helped me in a school work!
This was a really funny recap of the sacrifices we had to make in the building.
Thanks!
Absolutely fantastic teacher. He strikes the balance between making something accessible and--importantly--intuitive while also not watering things down too much or simplifying to the point of distortion. Really has the touch of a professor as opposed to a TH-cam educator, which I mean as a compliment. Sub'ed and look forward to looking at more content!
WOW!
Favourite professor ever. So thankful for you
I can't get over how good this video is, Professor. This makes everything so easy to understand. I have literally never enjoyed attending an online class as much as yours. You put me in such a good mood even at 8 am. Thank you
Now I'm blushing ... Thank you for the kind words.
Great explanation, many thanks, prof. Jeff.
Thank you, I appreciate it.
Well worded and very helpful
This lecture is ridiculously good, holy fuck!!!! All the analogies and real life examples are perfect/helpful
Wow what a great video! Thank you, it helped alot! 😃
I love how enthusiatic you are, really gives me a good vibe despite online school
Hello, I am a Brazilian student, could you quote me your bibliographic sources? Thanks in advance
Thank you
thank you
Well illustrated Jeff
HMBC may have enabled you to differentiate the two CH3 of the isopropyl and methyl with more certainty.
JKU & USB.
Thanks Jeff 👍
Thanks Jeff
Your way of delivering knowledge is amazing Thanks Jeff
Thank you very much, Sir
Not very clear on that glass, glad if you use black board
why in dept have 5 Ch2 downward?
It is interesting to learn about history and evolution of NMR before things got all digital.
Very well explained Jeff Orvis, i think it is 4bn instead of 400bn. lovely lecture
400MHz is 400 million...
Great and thanks professor Jeff
Your welcome.
thank you very much for such a nice explanation sir ❤
Muchas gracias!!!!!
You helped me pass my exam, thank you!
Excellent. Glad It was helpful.
Thank you Sir! Finally I found a good explanation for this phenomena!!
Useful Thanks Jeff