Mr Murray-Green Chemistry Tutorials
Mr Murray-Green Chemistry Tutorials
A-level Chemistry tutorials following the OCR (A) specification but suitable to most UK exam boards.
Some videos in collaboration with Ashton Sixth Form College (ASFC Chemistry), Greater Manchester.
I’m also on TikTok as @mrmurraygreen as of September 2022!
Check out the Google sheet with all my videos organised by module in the links below!
Пікірлер
thank you
You're welcome
You are good👏
in school i was taught that the lone pairs also are contributing to the chiral centers, so the NH(secondary amine) has a lone pair with 3 different groups, so it is a chiral center, if this thin is true then tertiary amine also has a lone pair, in total having 4(in the video) + 2 = 6
Hi, an excellent question! Pyramidal nitrogens which are bonded to 3 different groups (whilst still having a lone pair), e.g. amines like you mentioned, are classed as achiral as they invert their own shape at RTP back and forth between their own isomers. Therefore we do not include them in the count. If we were able to create conditions where the inversion doesn’t happen then we would include them.
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Total no. Of stereocentres in this?... 7?
Amen.
But Cis - Z And Trans - E . Can this happen? 🤔
Z and cis are not mutually exclusive (neither are cis and trans) here is some more guidance = kzread.info/dash/bejne/nX9lupSbZqaue6g.htmlsi=ysmM0gei_9RIEb-t
@@mrmurraygreen yess I got it clear now. Thank Youu ❤️ and Subscribed✨
When I asked my teacher how to dicipher skeletal structure she explained it in a way where all I heard was "Hydrogen... Something, something, something... Hydrogen and something else..." This video helped so much. To be fair im only in year 9 but I want to know advanced science early to make it easier for myself in Biology and Chemistry A Levels in 2 years time.
Hello prof. Your teaching is excellent and really helps me understand the material. It would be great if you could upload longer videos soon for more in-depth teaching
Hi, thanks for the feedback, I’m off KZread until the new academic year. Take care.
Hi Sir I don’t get the last question I thought NH4 + ammonium ion is a base
No it’s an acid as it donates a proton
@@mrmurraygreenwhat if the product is not given Sir? I can identify but I can’t just come up with the product?
Sorry but I don’t know what you’re asking?
@@mrmurraygreen what if it was only given NH4+ + Co32-
Like it would want us to find the product by ourselves
Hello prof. You teach Chemistry very well you deserve millions of subscriber and millions of views and I am wondering if you have uploaded the lecture on atomic structure. Thanks!"
Hello, thanks for the feedback, and I’m sorry but I’m not sure what you’re referring to? I don’t remember saying I would be uploading a lecture on atomic structure?
@@mrmurraygreen I hope you're doing well. I wanted to ask if you have uploaded the lecture on atomic structure. I couldn't find it in the course materials and wanted to make sure I haven't missed it. If not, could you please upload it?
Sorry but what lecture on atomic structure?
all my videos are in the 2 ‘year 1’ and ‘year 2’ playlists on my channel - hopefully what you want is in there 👍🏻
@@mrmurraygreen I wanted to ask if you have also uploaded the lecture on the wave properties of radiant energy and the electromagnetic spectrum. "Thanks for your time and assistance"
I got an E in my chemistry mock in January ever since then started watching ur videos and I honestly feel so good finishing my chemistry A-level with a smile mostly thanks to you ❤!
I'm so glad! Well done for being resilient and sticking with it.
A 5 marker on making a standard solution came up in the unified paper today and it was almost exactly the same as this one! Thank you so much sir for all your videos, you helped me get through a level chemistry this year 😊
Glad it helped!
I hate paper 3
It’s Chemistry’s final boss battle
this paper is fun lol
was the reduction of Pb2O3 meant to have a 4 coefficient?
Hello - I think this is mentioned in the video description updates? Let me know 👍🏻
gonna miss your vids when I finish these exams:(
You say that, but one day I might be stood behind you in like a supermarket and you’ll hear my voice which then triggers loads of flash backs 🫠⚡️
hey which video is the web method in you module 5/6 playlist? what is the title?
Here you go = kzread.info/dash/bejne/g3esmcGworCbdco.htmlsi=7n9BWttgRgny7w9V
Hi teacher. Could you please make a video about how to differentiate E and Z isomers in NMR? It would be very useful
Hi sir, I haven’t commented before but I just want to let you know I watched this video this morning 20 minutes before the exam. I’ve never ever gotten an NMR question right but a very similar question came up and I’m confident I’ve done it well. Thank you.
That’s excellent news - I hope it went well 👍🏻
Thank you so much
tyyyy
By far the best explanation I’ve seen. Thank you sir! Also your video on blood buffers came in clutch for paper 1 🙏🙏🫶
can’t believe i’ve discovered this channel the day before my exam 😭
There’s still paper 3 too!
@@mrmurraygreen thanks i’ll be coming back. your videos are really good 🙏🏽
Thank you for the video! I have a question: why do carboxylic acids, esters and amides not react with 2,4 DNHP and form an orange precipitate even if they do have the C=O bond?
Your A-level limits ‘carbonyls’ to aldehydes and ketones and states that these are the only groups you need to know will form the ppt with 24DNP 👍🏻
2:31 - where did the water come from?
The NaBH4 is aqueous (although you don’t need to know this for OCR) and that’s the source of the water
thank you!! you explained it so perfectly
Glad it was helpful!
Hoping for a similar question tomorrow!
4:10 how can u tell it’s an aromatic peak just by looking at it?
Good question! Its position on the chemical shift scale and the very distressed splitting it has doesn’t follow a clear ‘roof’ shape like other peaks do. (i.e. other peaks go to a point in the middle using their splitting pattern)
@@mrmurraygreen ohhh ok thanks :)
Hi if you don’t already could you make a video on unfamiliar mechanics as I always lose marks on them thanks 😊
I see your request and raise you 2 videos on this very topic! kzread.info/dash/bejne/eaeVp8-kp8LFYbQ.htmlsi=BEpWUVK711rqy9n2 kzread.info/dash/bejne/nZ9musOpoNOefqw.htmlsi=LWAg_oCoQJxYQ74R
Hey sir wouldn't there be 5 proton environments in total as the cooh signal is missing from the nmr? So would the final structure only have 5 proton environments? I know I am wrong but wasn't sure why.
The final structure needs to have the peak which is removed by the proton exchange added back in
There tends to be questions that require you to find theoretical yield but inverse, have you got a video about that Sir
Like this? kzread.info/dash/bejne/c46WutZ8ibq2eps.html
Hi at 8.39. If you put peak at 2.4ppm quartet and 3 neighbouring but only put CH2 instead of ch3-ch2-co is that still considered correct or do you need the full structure at 2.4ppm to get the mark if that makes sense thanks
Edited! Sorry my initial reply misread what you asked! You should always show the immediate other section of the molecule that the peak you are analysing is bonded to. Use the chemical shift scale to identify possible functional groups and the splitting pattern to identify other H’s. That way I am able to say it’s not just a CH2 but instead a CH3-CH2-CO! Does that make sense? Does that answer your Q?
@@mrmurraygreenwanted to double check if you could get the mark without it. Because on some mark schemes the ch2 for example is in bold and the neighbouring aren’t. Sometimes I struggle with the neighbouring assignment and just the ch2 which would be in bold in the mark scheme but would that get you the marks e.g if it was for 4 marks and 1 mark represented one chemical shift analysis
@@mrmurraygreenif I’m stuck on what the neighbouring is would it be best to put the ch2 only which in mark schemes are bold or try and guess the neighbouring assignment . Cause for these they are usually 6 marks and 4/6 according to my teacher is for analysis for the nmr and since I stuggle with the final structure I am happy with getting the 4 analysis marks thanks
The bit in bold is the mark scheme’s way of showing what part of the molecule is responsible for the peak you are reporting on. You need to try and include the stuff around it to get the full analysis marks. Here are some general tips: How many H’s are in a peak comes from the relative peak area You can determine what functional groups it is bonded to based on its chemical shift data. Then you know how many H’s are on the next carbon(s) up based on the splitting pattern (and the n+1) rule. If you would like more practice with NMR then check out the year 2 playlist on my channel as there are lots of NMR tutorials in there.
@@mrmurraygreen thanks and one more questions if you get everything correct like all the analysis and attempted final answer but get it wrong how many marks can you get if it’s a six marker
Hey could you please go through the 2019 paper 2 q 21.
Hello, this will be posted tomorrow morning 👍🏻
@@mrmurraygreen great, can’t wait
Your content is different and I love it.
Thanks very much
Thank you for amazing vid as always Sir, any ideas on making vids for PAG practical? exam styled questions
Thanks 🙏🏻 There are lots in my Unified Chemistry walkthroughs playlist and in the level of response playlist already but I am always looking for feedback and this is a great suggestion. Perhaps a summary video before paper 3?!
Can you do more videos like these, like you did before paper 1, they’re very helpful
There’s more on the way and all the others are in this special playlist = kzread.info/head/PLBE4lu9fm3bRzNLzjEO60iE4eivi3pNZL&si=8-gJa5joPFqunKd3
if you have both a nitro group and a phenol e.g nitrophenol if you are adding another group what will be the resultant directing effect?
you would not be able to predict this perfectly
Hello Professor, have you also uploaded the lectures of Organic Chemistry?
Hi, all my videos are organised into the playlists on my channel. Please note that all my content is for A-level Chemistry.
@@mrmurraygreen "Thank you for clarifying. Could you recommend any KZread channels or professors who cover advanced organic chemistry?"
Try this guy = youtube.com/@theorganicchemistrytutor?si=GPTQkQIVF3c7un4x
@@mrmurraygreen Thank you so much for the suggestion! I really appreciate it.
Thankyou for this video, there was a question about this in the paper
Prof. my question is off topic I have a question that I couldn't find the exact answer on internet. Could you please explain why cyclooctatetraene [8] annulene), [16] annulene, and [12] annulene exhibit non-aromaticity, whereas [14] annulene and [18] annulene shows aromaticity?
Stumbled upon your channel accidentally, and I'm so glad I did! You teach chemistry very well, and I've already learned so much from your videos. Thank you for sharing your knowledge with us
Thank you very much for your comments but sadly I’m not sure I can help you. I have not studied the material you are referring to in a long time and it’s not part of the specification I teach at the moment. Sorry I wasn’t able to help on this occasion.
@@mrmurraygreen That's okay, I'll try to find the answer on my own. Thank you for your time.
this video is the reason i was able to smash that 5marker i owe you tons! was such a good paper!!
grade boundaries are unfortunately going to increase :( Thanks for all the help sir, time to rock paper 2 too!
OCR are very consistent with them and you shouldn’t need to worry.
I wrote 2 pages for this 5 marker, as long as I didn’t make any contradictory points, I can still get 5 marks right 😭
yes
@@mrmurraygreen Is it okay if there is an essence of Biology protein tertiary structures mixed up in that 2 page 🥲
@@Naim54321 aha i added a tiny bit of that
They would probably ignore it rather than use it against you. Try not to worry.
The question came up omg
I'm so amd, i forgot how to do it. Despite doing it at home and doing it correct. Absolutely fuming. Just blanked out
Don’t worryyy
So glad I watched this yesterday as a very similar question came up for OCR
Good! I’m desperate to see the paper
@@mrmurraygreen I thought it was pretty easy overall. No really hard questions!
Hi sir would you be allowed to write ‘w.r.t’ in the exam. It always takes me ages to answer these as I write everything out in full. Can you also out the concentrations as brackets and write x2 for 2nd order?
Hi, the way I have written all of this is how it very often appears in mark schemes - including the wrt bit :) Just be careful as the x2 is meaning doubling not second order.
@@mrmurraygreen Ok thank you so much sir, and your videos have helped me so much over these past few months, I hope paper 1 tomorrow goes well!
Best of luck!!
2:56 , did you mean to write nh3 or h20?
Hi there, my equations at that time stamp look right to me? I’d be happy to help if you are able to expand a little please?
ohh, its a separate reaction, you were talking about how you can form the complex ion from the precipitate whilst you were on the other slide writing down a separate equation I got confused. but all good!! sorry about that haha. btw great video
No problem at all! It’s probably my fault trying to match my own voice over to my writing haha. Glad you got it and thanks for watching :)
please my exam is tomorrow can you just answer this question for me, why is it 2- on the cucl4 ?? thank you
lets hope this comes up tomorrow :) Thanks as always for your amazing videos Sir...
Hey recommend watching Machem guys playlist on this topic as well because they can ask this in a lot of ways and Machem guy went through all of them