Hey, I am a human from the future. That is not how it actually works. You see, different situations, environments, and some other stuff contribute to what will ensure the most efficient teaching and learning. In a classroom environment, this teacher could have difficulty sharing the exact same information within the same time frame, with the same voice tone, and with no package loss. haha. Due to it being a video there are no other students to provide distractions and thus increase the duration of the lesson and package LOSS!!!!! dun dun dun. Indeed my friend, sitting alone watching a video and taking notes is not comparable to being in a class with other people. In the same way, you can not compare flashcards with just reading the notes. Both work well, but to what extent, and for who? WHO WHOO .... this reminds me did you know, owls hunt other owls? Maybe we should alert the parliament of owls. haha, owl puns are fun. Do you know what else is fun? Finding out whether we live in a simulation and to find out why our miserable souls have been placed on to the earth, why we are not who we think we are, Why we exist!!!!! AND Why I will never be able to finish all of the game theory and vsauce videos in time for tonight's anime marathon.
I wish my Chemistry teacher was half as good as you, everyone in my class uses your videos for revision/learning. Thank you for all the effort you put into them
Keep doing past exam questions please, I find it unbelievably helpful when you go over them identifying where the marks lie! Thanks for all your videos, amazing work!
You are currently saving me from being failing AS Chemistry all together. I come home after a lesson and just switch your videos on straight away because my teacher teaches me nothing (He thinks he is a million times better at teaching than he actually is). I am constantly getting told I shouldn't be doing Chemistry, but thanks to you I am actually understanding all the content, because I am actually learning and being taught it. I sit on a evening playing you videos with my textbook open as if it was a lesson. (Because I am clearing gathering nothing from my actual lessons.)
+Sophie .Jayne That all sounds like a right hassle. But I'm glad you're coping and finding ways to deal with things. Let me know if there's anything I can help with and keep working hard!
I'm so lucky I have a friend who recommended you to me, I've got two weeks to sort out my grades before my mocks and I might actually do it with these videos, I'm understanding chem so much more already
Seriously thank you so much for these videos, I have been basically teaching myself Chem and I have learned more from your videos in one day then the entire month and a half I have been in school! Thank you!
so easy to understand when you explain chemistry, I cant seem to take it in with my current chemistry teacher you're a great help thank you. I will watch you all the way through my A levels :)
this is video is very good, had trouble with intermolecular from months. This helped to understand a lot and also had qns discussed . Thanks sir for the video
Amazing video thank you!! Btw it is soooo helpful when you go through the relevant exam questions at the end it really made me fill the gaps in my knowledge!!
than you sooo so too much for your amazing videos I missed a lot of school because I had a lot of tournaments last term but I'm catching up because of your videos... I won the chemistry prize last year and I will credit it to your help as well as my brilliant teacher who unfortunately left our school last term.... thank you so ,much
Thank you soooo much for your videos. I didnt do so well in my previous exams but for the first time...just looking at your videos I am finally understanding the subject. Thank you very very much :D
Thank you! This was really tough to read about as it requires lots of thought. I tried the exam questions at the end before you give the answers and I got them all right apart from the last one. I mentioned that "Hydrogen bonding only takes place between molecules with partially negative Oxygen, Nitrogen and Fluorine atoms attracted to molecules with partially positive hydrogen atoms" I didn't mention the phosphorus's negativity :s
What a coincidence, just been doing a bit of revision on this exact topic as vdw came up in a u1 exam and I was getting a bit confused, good video as always!
Your videos are absolutely amazing! I'm understanding chemistry so much more with your explanations.... thank you so much! Also, I was wondering what you mean by the titles of these videos "NEW & OLD SPEC", are you referring to the new 2016 SPEC or does "NEW" mean the 2015 spec? I'm asking because I've realised this video was uploaded on Feb 2015.
Haha, it's funny how my AS Chem qualified (somehow) teacher learns from your videos too. He doesn't even know why cinemas have staggered seating. He's probably reading this whilst he's teaching...his mouth how to consume crisps. Nice to see you continuing your videos, keep up the good work.
Just a quick observation. In question 1c) I’m pretty sure the strongest intermolecular force would be van fer waals. This is because the molecule will adopt a tetrahedral shape in which the dipoles will cancel out and it won’t be a polar molecule.
only started my as levels and your videos are great for me, I have fun and learn whilst watching them, only wish that there were these videos for biology aha, thanks very much.
Hi, I was just wondering, when at 30:11 in the video, how you identified that there were three lone pairs? Is there a set number of lone pairs for a Fluorine (and Oxygen and Nitrogen) atom or did you use the method from the shapes of molecules video? Or am I wrong in both of those suggestions? Sorry if I'm just being stupid! Thanks in advance, your videos are great!
Matt Grigg Just by looking at the electron configuration for fluorine - using the GCSE model, we can see that there are 7 outer-shell electrons. One of these has to be used for the bonding, leaving 6 which are all lonely. That help?
Did you make a video on electronegativity?? Since you knew straight away the differences between electronegativity when predicting the hydrogen bonds.. Also for the last question could you have wrote there isn't lone pairs in phosphine or is that wrong? Many thanks.
Just to make sure, do the examiners allow the use of the three dots for a shorter way to say therefore? By the way these videos are really helping me out thanks a lot for your effort.
i was having a hard time learning this as I'm currently a GCSE student studying a levels independently and your videos are bangin'! thanks for making this channel!
Sir, when we are finding out the electronegative difference for dipole-dipole ......what is the range for the big difference in electronegativity??? 35:54
+Vanessa Costello Yep. What I've written is 100% correct. The reason is due to the bonding being simple molecular. In this bonding the weak VdW forces play a key role.
Hi, can you do exam questions at the end of every video please as they are really helpful and can you make a video on electronegativity and which parts of the spec it links to?
Just outta curiosity do you reckon you can give a link in the description of AQA exam past questions specific to the video? E.g in this case a question on Intermolecular Forces? :) Your vids are really helpful btw
Thanks, You're videos are amazing but i was just wondering about a few things. at 26:30 do HI, HBr and HCl have dipole-dipole bonding? Also at 31:36 would you talk about bonding (i.e. covalent bonding) because the question says in terms of bonding or can this also mean hydrogen bonding?
I am really stuck on this aspect of dipole dipole molecules. Basically, our teacher said that sometimes the delta postitve and delta negative bonds can cancel each other out, and so even if a molecule has permanent dipole bonds, it may not be a polar molecule overall, and will have no charge. Such as C02. I don't understand when these charges cancel each other out?! And I don't think you covered that in this video. The first exam question you did, you said the strongest force was the dipole dipole force, but wouldn't the charges just cancel each other out on that molecule. Sorry for the long question, and if I sound stupid but I would really appreciate it if you could help me out. Thanks
+Amy Yeah, I just had this very conversation with my Lower 6th group the other day. The video isn't as heavy on polarity and electronegativity as it maybe should be, but I am going to be making changes to the videos over the next little while to break them down into more manageable chunks! The way I explained it was that in some molecules, we have polar bonds. In a molecule such as HCl, the bond is polar. This molecule is also polar and therefore has a permanent dipole. Whereas, in a molecule such as CCl4 (methane with each hydrogen replaced by a chlorine atom), the C-Cl bonds are all polar, but basically the partial charges are balanced throughout the molecule and therefore cancel each other, leading to no permanent dipole. If you look at the shapes of the CCl4 molecule, you will see that it has some kind of symmetry and no matter which way you turn it, it is basically the same molecule. I should say at this point that a permanent dipole comes from an uneven balance in a molecule (or what I described as the molecule being wonky). Using the CCl4 example, but swapping one of the chlorine atoms for a hydrogen to go CHCl3, we still have 3 polar C-Cl bonds, but because of the introduction of the hydrogen atom, we find that the over molecule is now not balanced in terms of its charge. This is because the C-H bond is NOT polar and so the whole thing becomes wonky and as such, we DO have a permanent dipole. Has that helped at all?!
E Rintoul Yes, this is really helpful thank you, I totally get why molecules can and can't be polar. So wouldn't that mean in the CCl2F2 in the first exam question you did, due to all the negative charges around the outside, wouldn't the charges cancel and so there would be no dipole-diple intermolecular forces? And so the strongest would be VDW?
Amy That's a little bit more of a tricky example as the chlorine and fluorine atoms have different electronegativities which would cause the bonds between them and the carbon to be different in terms of their polarity!
Eliot Rintoul I would absolutely love it if you were to do so. Even if you didn’t want to do every topic, just covering some of the harder AS topics like ‘The Immune System,’ ‘Oxyhemoglobin dissociation curves’ ‘Digestion of Lipids’ and ‘The Sodium Potassium Pump’ it would really help a lot of students! :)
sorry im still a bit confused. as in how do you know CCl2F2 had dipole dipole but CH4 is just van der waals. like how can you tell which one does and doenst
+campervan20 I'm not the uploader but hopefully I can help :) What I do is draw out the molecule and then label where the electrons are being most attracted using an arrow. I always go positive to negative. When I'm done, I look at opposite ends of the molecule and if they have separate charges, there is a dipole and hence dipole dipole forces. If not, there's just VdW's.
hi, recently I discovered ur channel and I must say that I am loving it. but I find it difficult to watch a full 30 to 40 minute videos so would it be possible for u to cut it down in sub topics?? thanks once again 😁😁
+Krupali Parikh I've cut some down into smaller topics. I am aiming to cut others down, but I don't know when I'll get around to it. My advice would be to just watch a small portion at a time!
Yo Mr Rintoul, One thing that tripped me up was the H2S, H2Se, H2Te graph. These molecules have permanent dipoles and hence dipole-dipole forces right? So why do we have to talk about the VDW forces?? Thanks in advance
***** Alright, chap? Nope, no permanent dipoles there. You're best to think of permanent dipoles occurring only where we have halogens involved. That help?
34:10 - surely the increased size in the iodine atom leads to more/stronger VdW forces between molecules which needs a larger amount of energy to break the bond? I don't understand why you mentioned electrons?
One thing on that very last question (why no H-bonds in phosphine). There is a lone pair present, so you might reasonably expect an H-bond. But as you say, despite that, the P-H bond has so little electronegativity (compared, say, to N-H in NH3) that it outweighs everything else. Only 1 mark, I know. But in light of your earlier description of the importance of the lone pair in H-bonding, perhaps worth pointing out here.
As well as an adjacent hydrogen, you also need a highly electronegative atom with a lone pair: oxygen, nitrogen or fluorine. Phosphorus isn't electronegative enough. A little late, but hope that helps! 🙂
You are an amazing teacher!!! I wish you were my chemistry teacher at school!! I understood everything except for the phosphine one. Why can't H-bonding take place with Cl? Chlorine is more electronegative, right? I would be grateful if u could clarify it in the comments
I know it sounds like a stupid question but at what point can you determine that a molecule has enough electro-negativity for a dipole-dipole interaction to take place, for instance in your final answer to the PH3 question. Is there a sort of line or rule between any 2 elements for instance where anything after makes it acceptable to make it a dipole-dipole interaction and not just VDW, or a certain amount of blocks in between? Also your videos are Ineffable, thank you ever so much!
Mo Tayee Be careful - I'm not saying that it would be permanent dipole in that question, just that the difference in electronegativity is not enough. Because you don't need to know, or use, specific values, you need to make sure you know of the specific examples given. Hydrogen bonding only occurs when we have nitrogen, oxygen and fluorine atoms (not all at once!). The easiest way to think of the permanent dipoles is when you have halogens involves. For example, a H-Br bond or a C-Br bond. That helped at all?
So we can have a dipole-dipole interaction (permanent dipole) when there exists a halogen? However i can sort of identify sometimes when there's a dipole-dipole, just confused/puzzled at what extent of blocks in between 2 elements where we would identify the type of interaction, similarly like we have the metals and non metals, there's a line where we can identify which element categories into which state, However yes that has made it understandable, Thankyou!!
34:26 can you say that iodine has a bigger atomic radius than fluorine and therefore has more electrons and so requires more energy to break vdW’s forces ? Rather than saying that iodine is bigger ? Does it mean the same thing and will it get you the marks ?
Are dipole-dipole considered Van Der Waals too? The revision assistance guide (wjec) is treating both dipole-dipole and induced dipole as van Der Waals forces.
Thank you for this video I feel I understand however there are definitely gaps in my knowledge.. 1) how do you know if a molecule is electronegative and which one is more than another? and 2) how do you know how many lone pairs a molecule contains?
I have a question. Say in a question you are given a molecule like CCL. or something odd that doesn't involve hydrogen hydrogen, how can you tell if it has a permanent dipole dipole, how can you tell if the electronegative is great enough for there to be a permanent dipole? btw your videos are amazing! They are very helpful for my chem revision :D
Kenko Shaft Hi, Kenko. The basic thing would to be to say that it would be obvious i.e. HCl or CCl. Pretty much a situation where you have a halogen attached to a hydrogen or a carbon. That help?
For question 1 (c) - I thought the dipoles would cancel because the shape is tetrahedral (four delta negative halides are surrounding the carbon atom? And therefore van der Waals are the only intermolecular forces present? I could be completely wrong though.
one question- why does the electronegativity change in iodine molecule ..resulting in induced dipole? what causes this difference in one side of the bond being more positive and the other more negative??
If unsaturated fats are liquid at room temperature due to their shape causing them to have weaker VDW forces, then where does the part about double bonds come in? Wouldn't it make more sense if they were solids at room temp because breaking double bonds requires more energy than single bonds? How do they have double bonds if the VDW are weaker and the bonds are easier to break than saturated single bonded fats?
+Mina Siu there isnt really a difference, its just the difference in electro negativity between hydrogen and F,O and N are so big that they have a different name.
+Mina Siu The dipole-dipole occurs when the electronegativity difference is big enough to allow for it (can't think of the value off the top of my head). H-bonding is similar in that it involves a big electronegativity difference between the O/N/F and H, but it has to involve O/N/F and H.
I wanted to ask, in the questions about fluorine and hydrogen fluoride, why did you assume to talk about intermolecular forces rather than the bonding because it did ask about bonding?
These videos are really helpful but I have a confusion. What if an ionic substance is given and we are asked to give reason for its high melting point so what will we relate are answer to the strong electrostatic force of attraction OR the dipole dipole forces?
+Hamza Abdullah It has no dipole-dipole forces. The only time you talk about IMF is in the case of simple molecular substances. For ionic, only talk about the electrostatic forces.
The students you teach are so bloody lucky to have you as a teacher
+IshyB135 I'm not convinced they would agree... but thank you for the kind words!
+E Rintoul lol wait till they get their results then I'm sure they will :)
Oie 1 mahina agadi ko chem test ko lagi padira?
lmao
Hey, I am a human from the future. That is not how it actually works. You see, different situations, environments, and some other stuff contribute to what will ensure the most efficient teaching and learning. In a classroom environment, this teacher could have difficulty sharing the exact same information within the same time frame, with the same voice tone, and with no package loss. haha. Due to it being a video there are no other students to provide distractions and thus increase the duration of the lesson and package LOSS!!!!! dun dun dun. Indeed my friend, sitting alone watching a video and taking notes is not comparable to being in a class with other people. In the same way, you can not compare flashcards with just reading the notes. Both work well, but to what extent, and for who? WHO WHOO .... this reminds me did you know, owls hunt other owls? Maybe we should alert the parliament of owls. haha, owl puns are fun. Do you know what else is fun? Finding out whether we live in a simulation and to find out why our miserable souls have been placed on to the earth, why we are not who we think we are, Why we exist!!!!! AND Why I will never be able to finish all of the game theory and vsauce videos in time for tonight's anime marathon.
@@giornogiovanna3139 thanks for your words of wisdom Giorno 👍
You are actually going to save my AS grade
+Ijaz Sultan Haha that's not at all true but thank you nonetheless!
+Ijaz Sultan SAME
tea.
I wish my Chemistry teacher was half as good as you, everyone in my class uses your videos for revision/learning. Thank you for all the effort you put into them
Keep doing past exam questions please, I find it unbelievably helpful when you go over them identifying where the marks lie!
Thanks for all your videos, amazing work!
+Max Raven I certainly shall do! And thank you for the kind words!
You are currently saving me from being failing AS Chemistry all together. I come home after a lesson and just switch your videos on straight away because my teacher teaches me nothing (He thinks he is a million times better at teaching than he actually is). I am constantly getting told I shouldn't be doing Chemistry, but thanks to you I am actually understanding all the content, because I am actually learning and being taught it. I sit on a evening playing you videos with my textbook open as if it was a lesson. (Because I am clearing gathering nothing from my actual lessons.)
+Sophie .Jayne That all sounds like a right hassle. But I'm glad you're coping and finding ways to deal with things. Let me know if there's anything I can help with and keep working hard!
hi, how did your chem exam go
who's watching this legendary youtuber a day before the exam?
me but its in two days 🥲
Wish we had teachers like you here sir! You work help us a lot. Please never stop
your videos are so so amazing!! They're keeping me going strong through A-Level chemistry, thank you!!
+niamh_violet I'm very glad, Niamh!
Wow, understood all of it! Thanks so much you are a savior! Your students are hella lucky.
I'm so lucky I have a friend who recommended you to me, I've got two weeks to sort out my grades before my mocks and I might actually do it with these videos, I'm understanding chem so much more already
Seriously thank you so much for these videos, I have been basically teaching myself Chem and I have learned more from your videos in one day then the entire month and a half I have been in school! Thank you!
Video was made when I started year 7 now watching this in year 12 prepping for UCAS exams... time flies
I loved this video so much! Honestly, it helped me loads and made this topic super fun and easy to understand finally! Total game changer - very happy
so easy to understand when you explain chemistry, I cant seem to take it in with my current chemistry teacher you're a great help thank you. I will watch you all the way through my A levels :)
always saw ppl commenting these but here i am, wathing this a day before my as paper. feel like giving up but this man is keeping me going
So how was the paper ?
when u attempt past papers and apply the knowledge, it helps sooooooooooo much
this is video is very good, had trouble with intermolecular from months. This helped to understand a lot and also had qns discussed . Thanks sir for the video
Amazing video thank you!! Btw it is soooo helpful when you go through the relevant exam questions at the end it really made me fill the gaps in my knowledge!!
than you sooo so too much for your amazing videos
I missed a lot of school because I had a lot of tournaments last term but I'm catching up because of your videos... I won the chemistry prize last year and I will credit it to your help as well as my brilliant teacher who unfortunately left our school last term.... thank you so ,much
your videos are genuinely awesome I don't usually comment much but have to here bc they are so helpful! plz keep doing them!
You explain these in such a simple but understanding way
Thank you soooo much for your videos. I didnt do so well in my previous exams but for the first time...just looking at your videos I am finally understanding the subject. Thank you very very much :D
Thank you so much. Your clips really help. You might actually save my as grade in chemistry.
Thanks again 😊👌👌😊😊😊😊😊😊😀😀😀
Really great video! Love your no nonsense approach and the way you go through the exam questions is very useful. Thanks! :)
Thank you! This was really tough to read about as it requires lots of thought. I tried the exam questions at the end before you give the answers and I got them all right apart from the last one. I mentioned that "Hydrogen bonding only takes place between molecules with partially negative Oxygen, Nitrogen and Fluorine atoms attracted to molecules with partially positive hydrogen atoms" I didn't mention the phosphorus's negativity :s
Boro Jen xX Good work!
You are such a good teacher. Thank you for enlightening us with your knowledge
What a coincidence, just been doing a bit of revision on this exact topic as vdw came up in a u1 exam and I was getting a bit confused, good video as always!
Matthew Cooper A good coincidence indeed! Thanks!
This is brilliant, clear and easy to follow explanations ...finally I understand intermolecular forces. Thank you so much!
Your videos are absolutely amazing! I'm understanding chemistry so much more with your explanations.... thank you so much! Also, I was wondering what you mean by the titles of these videos "NEW & OLD SPEC", are you referring to the new 2016 SPEC or does "NEW" mean the 2015 spec? I'm asking because I've realised this video was uploaded on Feb 2015.
Haha, it's funny how my AS Chem qualified (somehow) teacher learns from your videos too. He doesn't even know why cinemas have staggered seating. He's probably reading this whilst he's teaching...his mouth how to consume crisps.
Nice to see you continuing your videos, keep up the good work.
Twenny Wan I'm sure your teacher means well! But thanks for the kind words!
You are an awesome teacher and it's not relevant, but I like your handwriting. Keep going with your good work!
Just a quick observation. In question 1c) I’m pretty sure the strongest intermolecular force would be van fer waals. This is because the molecule will adopt a tetrahedral shape in which the dipoles will cancel out and it won’t be a polar molecule.
only started my as levels and your videos are great for me, I have fun and learn whilst watching them, only wish that there were these videos for biology aha, thanks very much.
+Rega Ali I've considered doing some Biology videos... Maybe in the future!
+Rega Ali And thank you for the kind words :)
+E Rintoul yeah if u could do biology videos it would be great but for now these chemistry ones are brilliant
A-level is going to be so easy.. now I have found this TH-cam channel
I actually love you, and this subject... Great videos thank you! :)
+galefray Galefray, we barely know each other. But thanks.
@@MrERintoul people are just being thankful so just thank them instead of saying u don’t know them
@@zlayer_115 Lmao relax, he was just kidding.
@@galefray oh my b bruh
My exam is tomorrow, it’s 2am now, I’m cramming everything and your video was AMAZING..
every one has already said this but man you are a god send thanks a lot best teacher i have ever come across and that's through a video XD
Hi,
I was just wondering, when at 30:11 in the video, how you identified that there were three lone pairs? Is there a set number of lone pairs for a Fluorine (and Oxygen and Nitrogen) atom or did you use the method from the shapes of molecules video? Or am I wrong in both of those suggestions? Sorry if I'm just being stupid!
Thanks in advance, your videos are great!
Matt Grigg Just by looking at the electron configuration for fluorine - using the GCSE model, we can see that there are 7 outer-shell electrons. One of these has to be used for the bonding, leaving 6 which are all lonely. That help?
Yes, it helps a lot!
Thanks for replying :)
I wish I had found these videos earlier because they are so helpful! Kinda too late now but last minute cramming as my exams tomorrow!
Your videos help me so much lad, my teacher’s a mess I swear. Thanks a pile hie
I'm in love with A-Level Chemistry Mr Ritnoul. Cheers :)
Did you make a video on electronegativity?? Since you knew straight away the differences between electronegativity when predicting the hydrogen bonds.. Also for the last question could you have wrote there isn't lone pairs in phosphine or is that wrong? Many thanks.
3 years ago!!!!!!!!!!!!!! What grade did you get?
@@edwardjarvis3442 lol r u doing AS now hahahaaaa
Muna Ali yeahh why
@@edwardjarvis3442 so you are now doing A2 good luck man
Nah Ra is Radium :)
The graph should say Rn.
Good luck in the exam tomorrow, everyone!
Just to make sure, do the examiners allow the use of the three dots for a shorter way to say therefore? By the way these videos are really helping me out thanks a lot for your effort.
+FXRain Yeah for real! I love me some 3 dots.
THANK YOU sir for the effort and time you put into your videos
this was just fabulous hope there r videos on all AS A level topics
+peter sameh I love the word fabulous. Thank you for using it.
quick question. why can’t it be hydrogen bonding with something other than N,O,F that is electronegative
i was having a hard time learning this as I'm currently a GCSE student studying a levels independently and your videos are bangin'! thanks for making this channel!
Thank you my dude. Glad I found your channel.
thank you so much, love the question solving part. Brilliant way to teach!
Thank you so much your videos are soooooooooo helpful! God bless you.
for question 1e) at 32:30, can you mention F2 is monoatomic and therefore will have weak van de walls due to its small molecular size
Thank you so much for making these videos!! Your explanations are so clear and easy to understand :)
Sir, when we are finding out the electronegative difference for dipole-dipole ......what is the range for the big difference in electronegativity??? 35:54
32:30, bonding? What you stated was an intermolecular force, is that right or I'm missing something here?
+Vanessa Costello Yep. What I've written is 100% correct. The reason is due to the bonding being simple molecular. In this bonding the weak VdW forces play a key role.
Hi, can you do exam questions at the end of every video please as they are really helpful and can you make a video on electronegativity and which parts of the spec it links to?
Just outta curiosity do you reckon you can give a link in the description of AQA exam past questions specific to the video? E.g in this case a question on Intermolecular Forces? :) Your vids are really helpful btw
Never mind! Watched the bit where you do some of the Past Paper questions!
***** Spot on!
Thanks, You're videos are amazing but i was just wondering about a few things. at 26:30 do HI, HBr and HCl have dipole-dipole bonding? Also at 31:36 would you talk about bonding (i.e. covalent bonding) because the question says in terms of bonding or can this also mean hydrogen bonding?
I am really stuck on this aspect of dipole dipole molecules.
Basically, our teacher said that sometimes the delta postitve and delta negative bonds can cancel each other out, and so even if a molecule has permanent dipole bonds, it may not be a polar molecule overall, and will have no charge. Such as C02. I don't understand when these charges cancel each other out?! And I don't think you covered that in this video.
The first exam question you did, you said the strongest force was the dipole dipole force, but wouldn't the charges just cancel each other out on that molecule. Sorry for the long question, and if I sound stupid but I would really appreciate it if you could help me out. Thanks
+Amy Yeah, I just had this very conversation with my Lower 6th group the other day. The video isn't as heavy on polarity and electronegativity as it maybe should be, but I am going to be making changes to the videos over the next little while to break them down into more manageable chunks!
The way I explained it was that in some molecules, we have polar bonds. In a molecule such as HCl, the bond is polar. This molecule is also polar and therefore has a permanent dipole. Whereas, in a molecule such as CCl4 (methane with each hydrogen replaced by a chlorine atom), the C-Cl bonds are all polar, but basically the partial charges are balanced throughout the molecule and therefore cancel each other, leading to no permanent dipole. If you look at the shapes of the CCl4 molecule, you will see that it has some kind of symmetry and no matter which way you turn it, it is basically the same molecule.
I should say at this point that a permanent dipole comes from an uneven balance in a molecule (or what I described as the molecule being wonky).
Using the CCl4 example, but swapping one of the chlorine atoms for a hydrogen to go CHCl3, we still have 3 polar C-Cl bonds, but because of the introduction of the hydrogen atom, we find that the over molecule is now not balanced in terms of its charge. This is because the C-H bond is NOT polar and so the whole thing becomes wonky and as such, we DO have a permanent dipole.
Has that helped at all?!
E Rintoul Yes, this is really helpful thank you, I totally get why molecules can and can't be polar. So wouldn't that mean in the CCl2F2 in the first exam question you did, due to all the negative charges around the outside, wouldn't the charges cancel and so there would be no dipole-diple intermolecular forces? And so the strongest would be VDW?
Amy That's a little bit more of a tricky example as the chlorine and fluorine atoms have different electronegativities which would cause the bonds between them and the carbon to be different in terms of their polarity!
E Rintoul Ok I think I understand it now, thank you so much for your help!!!
The way you talked about Dnaa and replication in this, you should consider making biology videos!
+Glitterfm2133 It's something that I've toyed with, and I used to teach AS Biology as well, but I don't know...
+E Rintoul PLEAAAAAASE DOOOO
Eliot Rintoul I would absolutely love it if you were to do so. Even if you didn’t want to do every topic, just covering some of the harder AS topics like ‘The Immune System,’ ‘Oxyhemoglobin dissociation curves’ ‘Digestion of Lipids’ and ‘The Sodium Potassium Pump’ it would really help a lot of students! :)
sorry im still a bit confused. as in how do you know CCl2F2 had dipole dipole but CH4 is just van der waals. like how can you tell which one does and doenst
+campervan20 I'm not the uploader but hopefully I can help :) What I do is draw out the molecule and then label where the electrons are being most attracted using an arrow. I always go positive to negative. When I'm done, I look at opposite ends of the molecule and if they have separate charges, there is a dipole and hence dipole dipole forces. If not, there's just VdW's.
hi, recently I discovered ur channel and I must say that I am loving it. but I find it difficult to watch a full 30 to 40 minute videos so would it be possible for u to cut it down in sub topics??
thanks once again 😁😁
+Krupali Parikh I've cut some down into smaller topics. I am aiming to cut others down, but I don't know when I'll get around to it. My advice would be to just watch a small portion at a time!
Yo Mr Rintoul,
One thing that tripped me up was the H2S, H2Se, H2Te graph.
These molecules have permanent dipoles and hence dipole-dipole forces right?
So why do we have to talk about the VDW forces??
Thanks in advance
***** Alright, chap? Nope, no permanent dipoles there. You're best to think of permanent dipoles occurring only where we have halogens involved. That help?
U Mad when you
34:10 - surely the increased size in the iodine atom leads to more/stronger VdW forces between molecules which needs a larger amount of energy to break the bond? I don't understand why you mentioned electrons?
I love your videos
You are so helpful
Thank you for your effort!
You my friend are AMAZING,
+Faisal Hussain Thanks, Faisal!
for question 1c) ccl2f2 wouldnt it be symmetrical so therefore nonpolar?
at minute 9:07 the symbol for radon is meant to be Rn
+Yas K Yep. It's an image I used from Google though, so don't shoot the messenger!
One thing on that very last question (why no H-bonds in phosphine).
There is a lone pair present, so you might reasonably expect an H-bond. But as you say, despite that, the P-H bond has so little electronegativity (compared, say, to N-H in NH3) that it outweighs everything else.
Only 1 mark, I know. But in light of your earlier description of the importance of the lone pair in H-bonding, perhaps worth pointing out here.
Dont think hes gonna reply m8
As well as an adjacent hydrogen, you also need a highly electronegative atom with a lone pair: oxygen, nitrogen or fluorine. Phosphorus isn't electronegative enough. A little late, but hope that helps! 🙂
You are an amazing teacher!!! I wish you were my chemistry teacher at school!! I understood everything except for the phosphine one. Why can't H-bonding take place with Cl? Chlorine is more electronegative, right? I would be grateful if u could clarify it in the comments
hey , ur videos have been a great help ! thanks for the uploads ! :)
sameh hossain No problem :)
Excellent Video ! Helped me alot, Thank You.
Umer Khan Spot on - glad it was of some help!
Hey man thank you so much from the core of my heart.....
couldn't have said it better! 👏🏼
I know it sounds like a stupid question but at what point can you determine that a molecule has enough electro-negativity for a dipole-dipole interaction to take place, for instance in your final answer to the PH3 question. Is there a sort of line or rule between any 2 elements for instance where anything after makes it acceptable to make it a dipole-dipole interaction and not just VDW, or a certain amount of blocks in between?
Also your videos are Ineffable, thank you ever so much!
Mo Tayee Be careful - I'm not saying that it would be permanent dipole in that question, just that the difference in electronegativity is not enough.
Because you don't need to know, or use, specific values, you need to make sure you know of the specific examples given. Hydrogen bonding only occurs when we have nitrogen, oxygen and fluorine atoms (not all at once!).
The easiest way to think of the permanent dipoles is when you have halogens involves. For example, a H-Br bond or a C-Br bond.
That helped at all?
So we can have a dipole-dipole interaction (permanent dipole) when there exists a halogen? However i can sort of identify sometimes when there's a dipole-dipole, just confused/puzzled at what extent of blocks in between 2 elements where we would identify the type of interaction, similarly like we have the metals and non metals, there's a line where we can identify which element categories into which state,
However yes that has made it understandable, Thankyou!!
Mo Tayee I would stick with halogens with hydrogen/carbon causing permanent dipoles. That should take some of the stress and strain away!
Much more sense, thank you so much!
34:26 can you say that iodine has a bigger atomic radius than fluorine and therefore has more electrons and so requires more energy to break vdW’s forces ? Rather than saying that iodine is bigger ? Does it mean the same thing and will it get you the marks ?
Are dipole-dipole considered Van Der Waals too? The revision assistance guide (wjec) is treating both dipole-dipole and induced dipole as van Der Waals forces.
how can we know that a specific molecule has enough difference in electronegativity?
Thank you for this video I feel I understand however there are definitely gaps in my knowledge.. 1) how do you know if a molecule is electronegative and which one is more than another? and 2) how do you know how many lone pairs a molecule contains?
Hello,
May I know why the hell does CCl2F2 have dipole-dipole forces? Thanks! :D
Shouldn't the Hydrogen bond be aligned with the lone pair and covalent bond?
+Khalil Jiwa Should it?
+E Rintoul loooooool rintoul did u dirty there
Let’s go dude cuz of you I got A* in chemistry
I have a question. Say in a question you are given a molecule like CCL. or something odd that doesn't involve hydrogen hydrogen, how can you tell if it has a permanent dipole dipole, how can you tell if the electronegative is great enough for there to be a permanent dipole? btw your videos are amazing! They are very helpful for my chem revision :D
Compare their electro negativies?
*negativities
Lol but u don't have a exact measure in a exam...
Kenko Shaft Hi, Kenko.
The basic thing would to be to say that it would be obvious i.e. HCl or CCl. Pretty much a situation where you have a halogen attached to a hydrogen or a carbon.
That help?
Carmel Mould In an ideal world, yeah. BUT, you aren't given any values in the exam!
you are incredible. thank you
mate absolutely epic
Thanks alot bless up am rilly getting 🙏
For question 1 (c) - I thought the dipoles would cancel because the shape is tetrahedral (four delta negative halides are surrounding the carbon atom? And therefore van der Waals are the only intermolecular forces present? I could be completely wrong though.
This was very helpful thank you so much
yes!!!! i understood thank you very much for this vdeo kpt up
+Pradeep Dc Excellent! Well done :)
So basically van der waals forces are a weaker version of dipole-dipole forces because they create a temporary dipole instead of a permanent one?
one question- why does the electronegativity change in iodine molecule ..resulting in induced dipole? what causes this difference in one side of the bond being more positive and the other more negative??
It is completely random
If unsaturated fats are liquid at room temperature due to their shape causing them to have weaker VDW forces, then where does the part about double bonds come in? Wouldn't it make more sense if they were solids at room temp because breaking double bonds requires more energy than single bonds? How do they have double bonds if the VDW are weaker and the bonds are easier to break than saturated single bonded fats?
What is the difference between H bonding and Dipole dipole? Is H bonding only for atoms that are electronegative with lone pairs?
+Mina Siu there isnt really a difference, its just the difference in electro negativity between hydrogen and F,O and N are so big that they have a different name.
+Mina Siu The dipole-dipole occurs when the electronegativity difference is big enough to allow for it (can't think of the value off the top of my head). H-bonding is similar in that it involves a big electronegativity difference between the O/N/F and H, but it has to involve O/N/F and H.
That's very clear bro. Thank you so much
For question 1c why is the answer not vdw forces? The molecule is symmetrical, so it is non-polar and so no permanent dipoles?
thank you for these videosss!!
My teacher recommended you, and i can say that in a matter of a few weeks, my overall working grade has gone from a C to an A ..;)
Defintion of electronegative? It might've been in the video but I've watched it in parts thanks.
I wanted to ask, in the questions about fluorine and hydrogen fluoride, why did you assume to talk about intermolecular forces rather than the bonding because it did ask about bonding?
These videos are really helpful but I have a confusion.
What if an ionic substance is given and we are asked to give reason for its high melting point so what will we relate are answer to the strong electrostatic force of attraction OR the dipole dipole forces?
+Hamza Abdullah It has no dipole-dipole forces. The only time you talk about IMF is in the case of simple molecular substances. For ionic, only talk about the electrostatic forces.