AQA A-Level Chemistry - Energetics Pt. 3 (Hess' Law)
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- เผยแพร่เมื่อ 24 ก.ค. 2024
- This is the final video that looks at the Energetics topic from the AQA A-Level Chemistry spec.
The video goes through Hess' Law before applying the theory to enthalpies of combustion and formation.
@Eliot Rintoul don't ever dream of deleting this channel you are literally a saviour and this channel is gold
whose here is 2024 😅
Night before paper 1😭
my exam is on Thursday i’m cooked😭
@@strawberrymxlkxo shouldny it be friday? Check ur timetable
@@IValchevno im not doing the official as exam it’s just a mock the organisation of my school does😭
hahaha at 8:19 when i saw your background i thought, what a teachery background to have, then i looked closer and realised!
tobais brown Haha, yes. I need to change that at some point...
@@MrERintoul no need to change its like a scientific background but from the pokemon world.
Thank you! After watching this, I did 3 Hess's law questions on Combustion and 3 on Formation. And 1 on reaction and I got them all right. I didn't have a clue about them before I watched this video! x
Jen xX Excellent work - keep it up!
a chapter which took a whole half term in about 15 minutes (watching on speed 2) lol
+Sam K Niceee.
Either your teacher is shite or your class is shit, or both :P Difficult topic though
bit of both haha
I failed my energetics test just becuz of hess law and this video made me a pro.... i can again think of getting an A in my As level
the fact that i actually put it on speed 2 to consume less time just shows how sad my life is
I've been struggling with this for a while but after watching your video I understood it straight away, thanks!!
Could you make a video doing some exam questions using Hess' law
I've been struggling with hess' law for two terms now! Really been of great help, thankyou so much, virtual hugs to you! xx
this topic scared me, now it just feels the simplest one.
you sir, have my respect
I finally understand them, thank you . I don't know what I'd do without these videos !
You're the best teacher ever! I can't thank you enough, this helped me immensely
This video has saved me! After my lessons, reading the textbook, homeworks and searching on the Internet I still could not understand Hess' Law at all! I now understand it completely in less than half an hour! Thank you Mr Rintoul! :)
You have literally saved me... My teacher this year has been dreadful and I've realised how little I know, I can't thank you enough :)
8:19
Darwin with pokeball XD
nice wallpaper
Great videos and great pokemon wallpaper. You've helped me allot so thank you.
Ur an actual saviour and genius to how u managed to get all that detail into one video im baffled my teachers at school spent an hour to tesch us and u managed to get the same amout of content in 23 minutes im shook😭😭😭
you sir ARE A HERO TO ME,I CANT THANK YOU ENOUGH.
Ahmed Qasim Thanks!
Great help thank you so much. I was struggling with this topic for almost a week and this video/ playlist really helped me!!
OMG THANKYOU your videos save my lifeee I swear!! May the almighty bless youu and shower you with happiness
Thankyou so much for these videos they are helping me get through as chemistry. I honestly wish you were my teacher ... thankyou so much for what you do
thank you so so so much! i was just about ready to give up on this stuff but your video has really helped! I can't keep going back to my teacher and asking her when i forget how to do it all so it's really helpful watching your video:)
Thanks soo much for your videos, it has been very helpful, my teacher goes very fast at school and your videos helps me understand it much better, thanks!!
sam09 It's tricky to keep the pace sometimes in class, particularly with so much content to cover (I'm sure some of my students would say my pace is a little quick at times!). It's definitely worth having a word with your teacher after the lesson one time, just to let him/her know that you find the pace a bit quick and ask if they could just slow it down a touch!
i have my exams and this is what i am dependent on, you're a saviour
You are an icon and a life saver- thank you so so much for this! It’s all starting to make sense 😁
i know im 6 years late here but I'm so confused, I've finished year 11 and I'm trying to teach myself the AS portion of the chem a level from your vids and so far I'm doing great but this hit me like a tonne of bricks. thankyou so much for the time you put into these though!
Same!!! Haha, we'll get through it :)
Why would you ever want to teach yourself AS chemistry?
THANK YOU SIR I JUST SAT MY ALEVELS IN MARCH BECAUSE U ARE TOO GOOD! THEY CHANGED THE SPEC JUST FOR YOU!!! UR A STAR GOD BLESS!!! U BEAUT
Man hats off to you
my teacher at school is terrible at teaching enthalpy
she took like 7 lessons to teach the whole energetics
whereas it takes 3 lessons to do a whole topic
and she cannot explain the simplest thing
man thanks a lot Appreciate your help
keep it up
your an amazing teacher
same but its the class aswell. My class fuck about way too much lool and then we all wonder why we are on grade U's
thank you so much your videos will help me pass my as level, my teacher at school is so bad now i still have hope in scoring good in chemistry!
Thanks to your videos I undestand chemistry- you are honestly the best teacher. Thankyou so much, if I get into medical school it will be because of your amazing work. :)
Style Street Well I hope you do get into Med school! Keep working hard!!
@8:19 Sir Darwin! Awesome video, I was really confused in class but it's all good now :)
Thank you so much!!! My teacher unsuccessfully taught this to me, but this video has literally helped me crack it in 20 minutes!!!
Sean Frost Excellent!
just gonna drop a message to say how much all parts have helped me understand the topic as a whole!! leaving this here so i can come back and see how i am in the future because at the moment i have no idea what i’ll be doing😪
Thank you so much for all these videos, i didn't have a clue about energetics , but now i do!
Luke Whiteside Excellent! Let me know if there's anything I can help you with.
Thank you so much!!! This is extremely helpful! I really appreciate your efforts❤️
Thank you this has helped so much with understanding Hess's Law. And now i feel prepared for my EMPA. :)
Fantastic! Good luck and let me know how it goes.
Could you go over finding enthalpy change of formation from enthalpy change of combustion? I have it in my text book and I cannot get my head around it! You're videos are actually saving me! No teacher until the start of this year (2016) and missing so many lessons due to clashes but these help me out so much!!
Thank you so so much, your videos are such a massive help, I really appreciate the effort you've gone though to make them!!!:)))
Zoe Dunnett No problem - thanks for the kind words!
youre a life saviour, thank you so much for your effort and time
These videos are also applicable to other exam-boards, I do edexcel and these videos are helping a lot! many thanks!
CogWerk That's good to know!
You're a life saver. I owe you my as chemistry a level.
TheAcesM It's all down to you!
Thanks a lot! Sitting here day before chemistry exam and had no idea about this
You doing ccea??
WOW JUST WOW. I cannot thank you enough. THANKYOU A MILLION!!!!!!!!!!!!!!
pringles lover Big praise! Thanks, though, means a lot!
Hi, how would you calculate the enthalpy change of a reaction when it provides both formation AND combustion data?? Im confused as to what directions the arror go to because one reactant has formation data with it and the other reactant has combustion data with it
You made this chapter so damn easy, at my school i was confused af with this. I couldnt do it, it felt like i was trying to learn chinese, but after this video :D!
Do you have a patreon page or a subbable account or something? It seems unfair that I've given money to textbook companies that have helped me a TINY amount, but I haven't given anything to this channel which has helped me LOADS.
TheThingsThat IDo What do you mean...?
E Rintoul It's just these videos have been insanely helpful to me this year, I was wondering if you accept like donations and stuff?
TheThingsThat IDo Oh I see! I guess I could set something up...! I certainly don't expect money from people! How would I even do it?!
E Rintoul haha I'm sorry, I have absolutely no idea :( I know there's a website called patreon that is meant to do stuff like this, but I don't know how suitable that is for you (I also hear rumours they take a cut themselves). Maybe a justgiving page or something?
TheThingsThat IDo Justgiving is charity though isn't it? Would a PayPal link work?
Uv given me an extra 2 hours of sleep bless you
a hero in our time
I do not understand what you put in the boxes with arrows, where do u get those 2CO2 + 3H20 from????? Last combustion question
Hi, great set of videos, massively appreciate you putting in the effort to make them. Just to add a little bit more (basically the easy method)- hope you don't mind checking if this is right and correcting me where necessary:
if you have enthalpy changes of formation:
enthalpy change = sum of enthalpy change of formation of products - sum of enthalpy change of formation of reactants
if you have enthalpy changes of combustion:
enthalpy change= sum of enthalpy change of combustion of reactants - sum of enthalpy change of formation of products
Hi and thanks for the comment!
You are absolutely correct. I don't like to simplify it like that purely because I think it takes away from the understanding, and I have seen a question in the past that actually gave a cycle to calculate a value from.
But, in 99% of the cases, your method will work perfectly (and is much easier!).
IM SO THANKFUL FOR THESE VIDEOS
+skyeline ozer I'M SO THANKFUL THAT YOU LET ME KNOW. Seriously, thanks for the kind words.
I think you explained everything really well. Thank you for this video.
tdd9977 No problem!
I couldn't understand what my teacher was teaching me , But you sir taught me well.
Thanks alot for your effort. I appreciate it. very well explained!
Ayush Acharya No problem!
Thank you very much for the video! its really useful!
Thank you for the video - really helpful in covid-19 lockdown!
This video helped me a lot, thank you!!
Thanks for the video I really understand Hess' cycle now. How would you do Hess' cycle with enthalpy change of reaction?
This is fantastic thanks very much!
DOING MY ALEVELS IN 5MONTHS UR LIFE SAVER
This man is a god, thank you
When working out questions do you have to be able to construct a Hess's cycle or is that just to aid you? This is because I can work out the answer for Hess's law questions by using the "cancellation method" if you've heard of it.
Why do values from mean bond enthalpy calculations differ from those determined using Hess’s law?
why we don't take in account the H2 in formation reaction and we take it in combustion reaction.?
It is request to you that Please make another video explaining the cycle in detail specially the part from enthalpy change of formation till end.
could you please make a video doing some exam questions of energetics, cause i do understand what you teach but i struggle with exam questions.
What's the difference between enthalpy of reaction formation and combustion, also why can you sometimes use enthalpy of formation to calculation enthalpy of combustion?
My autumn resit paper 1 is on 5th october, and ive not done much exam practise. Do you have any tips on how to structure my reviision over the next few days. Thanks, great vid
You're soo good omg ✨🙌🙌👏
I wonder if you are still active on this account. You posted this when i was year 6 and now im year 12 watching this amazing video.
Thank you so much! Everything makes much more sense now
I'm really glad you understand it better now! Thanks for the kind words.
What if we only make the ethane equation during the enthalpy change of combustion and use the reactants of that equation to find the enthalpy change?
thank you so much for these videos!! big help :) I have a question though: when do we use the Hess cycle and when do we use the formula: enthalpy= products-reactants?
+lamis shehata Thermochemical cycles are used when formation/combustion data is given and the other is used for bond dissociation enthalpies. I think that's what you're asking...?
so for the intermediates, do you always automatically use the ones with the highest coefficients?
Could you do a video with some exam questions on Hess' law
Great video
Awesome wallpaper, nd thanks for help
Amazing video!
Could you please explain how you know which way the arrows are going?
sir could you possibly do a vid constructing hess cycles using unknowns so you are given various reactions and you construct a hess cycle from the reactions given there's nothing on youtube going through it and i cant do it please help
Please make a video on enthalpy change of combustion by using formation data and enthalpy chanfe of hydration by using an anhydrous salt
(at 21:02) but if you leave it as 2H20 + O2 --> 2H2O and you dont have to multiple it by 2 to make a total of 3H2O... why would this be wrong?
With the thermochemical cycle at the end do you need to add oxygen to the reactants and products to make the reaction balance or does that not matter ?
Ryan Bower There's no need to add any oxygen into the cycle itself, no!
would really appreciate if u could also solve some past papers for both as and alevel chemistry , it would really mean alot
THANK YOU 😭🙏🏾
was a good explanation:) cheers
Can you explain how to work out the enthalpy change if they mix enthalpy change of formation with enthalpy change of combustion please?
+Daniyal Shah Have you got a question like that? I'd need to see the question to be able to do it justice.
Hi, could you please do an example question where the reaction itself is enthalpy of formation but the data given is enthalpy of combustion, I find questions of this type very confusing, thank you very much :).
Thank you so so much these videos have been really helpful! I was wondering if you would be able to do a video on mean bond dissociation enthalpies as I struggle with calculating them. Thanks! :)
mariobros920 Thanks very much! I have a video already I believe... Try this one: th-cam.com/video/Ks1CtqsafSg/w-d-xo.html
Let me know if there's anything else I can help with!
How do you know the enthalpy changes of the molecules please help
I'm confused 11.21 about arrow so 2C+3H2 make the reactant and the products
How come you did not switch the - for a + in the other calculation the enthalpy of combustion one you changed the -1560 but not any of the reactants?
Thank-you, was very helpful. Do we need to know about mean bond energies for the AQA board?
+Reian Taank Yep. Here: th-cam.com/video/Ks1CtqsafSg/w-d-xo.html
+E Rintoul Thanks for the quick reply :)
do you know where i could find a sheet with all the equations i need to learn for as chemistry ?
doctortrigger I can list them here...
moles = mass / Mr
concentration = moles / volume
% atom economy = (mass of desired products / total mass of products) x 100
% yield = (actual mass / theoretical mass) x 100
p.V = n.R.T
q = m.c.delta T
I think that's them all!
Is the first example a standard enthalpy of formation?
Thankyou so so much that helped a lot
9:40
So in this example, the value for the enthalpy of formation for H2 isn't given because you can't form H2 from it's constituents elements? Which is why you'd just take the value for the enthalpy of formation for ethyne only?
Thank you so much !!!
It's really helpful❤
How come H2 is considered in enthalpy change of combustion but not in enthalpy change of formation?
Amazing !!
Thankyou