Hess' Law and Enthalpy Cycles | A-level Chemistry | OCR, AQA, Edexcel

[@zuzannagradek9895]

The first 5 minutes of this video explained it better than my teacher did in one hour.

[@alexiaaa741]

periodt

[@hishaam2050]

Literally 😂

[@youlaynagorayah7057]

Omg same

[@raantaaro]

literally

[@Anonymous-rw8eq]

this amazing video helped me actually solve an enthalpy question!! it was only one mark but proudest moment of my life. Thank you so much!!!

[@officialm.a.d9168]

16:56 there is a mistake as it should be 9N2 not 5N2 for the constituent elements

[@darkChocol8]

yh i was confused af

[@bench2328]

EXACTLY

[@ronjohnson831]

on the same question, how did she get the 10O2 for the constituent elements? i don't see where that comes from

[@saintw3053]

@@ronjohnson831 (5x4)=20 oxygens (O) divide that by two - 20/2=10 (O2)

[@charliebrett7510]

Thank God i was like tf

[@Andy-ig9gt]

Is it just me or did one part of the vid repeat itself

[@elsiemazarura3711]

Maybe she meant to edit it out but forgot...

[@caitlinheaton9657]

YES

[@shawarmababa]

No, i found it weird as well in the first part that the there was a 2N in the intermediate of the cycle. But then they fixed it in the repeated one but having the intermediate as N2 which is the natural form of nitrogen at r.t.p cause this is a enthalpy change of formation

[@but_is_it_art_6657]

@@shawarmababa i am so thankful for this comment. Was confused for a sec

[@Ashiq.Ibrahim]

THANK YOU SO MUCH! I tried understanding this on my own for a few weeks to no avail, BUT NOW I CAN DO HESS CYCLE QUESTIONS. THANK YOU, Truly.

[@fliss1228]

AMAZING VIDEO I FINALLY UNDERSTAND HESS CYCLES THANK YOU

[@insaf2668]

Thank you so much , you literally saved my life from being miserable , literally thank you so much , I love you 😂❤️in a good way .

[@shegoisateddy]

This video was actually the only helpful one for me. I couldn’t get any of the others I watched ❤

[@emilystrudwick1835]

Okay I'm probs just being really stupid but I cant work out for the life of me why at 12:07 ish she says she putting in arrows of combustion but she puts in arrows of formation when it says to uses enthalpy change of combustion? can someone help please?!

[@liamdacre1818]

The video was really helpful. You explained it really well and I loved the diagrams and example questions

[@tomcurtis1827]

Day 1 in quarantine.. *I’m going mad.. I’m watching A Level lessons 6 months early*

[@gabriellita7236]

Same, nice idea. Are you still watching?

[@orangecamo_cinnamonrolls306]

Same. Are you guys also gassed that ur 1/3 through the course ?

[@gabriellita7236]

@@orangecamo_cinnamonrolls306 yep, as levels will probably be easy because of this

[@tomcurtis1827]

@Sirius Orange @Daily Football Its good to get a head start on stuff like this when you get the chance🤷🏼‍♂️

[@gabriellita7236]

@@tomcurtis1827 ikr, I also study it because I find it interesting. Other than that I would get bored otherwise as we have too much time with this quarantine.

[@rubayetalam4359]

Excellent teaching style, I comprehended really well .

[@tinotendachibvuri9267]

17:33 why is it 5N2 I thought it’s supposed to be 9N2. Do we not count the nitrogen’s on the 4CH3NHNH2

[@tggudo]

mfana your a snake

[@michaelpollard1719]

Seems like an error in the video to me

[@ayoubalmani2803]

Its just a mistake but it wont effect the final answer. I also got 9N2

[@daaniaamelia3048]

How do i find the intermediate? I understand the rest its just that part that I'm confused on

[@darkChocol8]

anyone else hears Emma Watson speaking?

[@WhitePicture.]

ExAcTlY! lol

[@Jeeves_0]

Other than similarities in accent, she sounds nothing like Emma Watson

[@cindyboateng4735]

It's veeeeeery true

[@eccentricOrange]

I feel like Hermione is explaining me Potions

[@lilggs4813]

6:30 (a) Under standard conditions (b) Understand those conditions It’s obvious but I wrote it anyway

[@hassanshahid2453]

You are an amazing teacher ❣️

[@euansimpson5010]

this was so helpful definitely a walk in the park now

[@alvardavidsson5933]

22:00 there's 18 O atoms in the intermediate stage?

[@ιη3ςςι0ηαητε]

yes I do agree with you, I have to say, although there are lots of errors, this video still provides me with enormous and immeasurable amount of help, I suppose that the author is deliberately making these errors and hoping that we can find them and correct them, which is an ultimate way of teaching

[@monisamujawar2232]

7:08 why are we not adding enthalpy of O2(g) for calculating A?

[@insaf2668]

I’m not sure if the correct definition but , an easy way during exam is just calculate the values that they give in the table since those are the ones to be calculated . Someone correct me if I’m wrong

[@Jennifer_Ade]

I think it's because the element is forming the element, in other words the element is forming itself so there is no enthalpy change, so it's just zero.

[@issy483]

it's already present as O2(g), so no bonds have to be made or broken in order to move to the next stage of the reaction where it is also present as O2(g)

[@MrLimeGamingContentAndFreeGFX]

at 12:59 arent the arrows for combustion meant to be facing towards the elements

[@SmallgirlbigGod7]

Also the enthalpy change of combustion is always negative. I think they made a mistake

[@physchemwithliz5879]

The cycle you draw depends on the type of data you're given, rather than what you're asked to calculate 🙂

[@chlo7390]

on the last question 22:03 does anyone know how she got 6CO2?? im probs being slow but i thought there was only 6 oxygens not 12

[@mayhemmbtw]

It's a combustion, so they're reacting the molecules already there with oxygen (aside from the oxygen already there). That's why you get more oxgen in the molecules after the combustion has taken place

[@cedcol356]

16:50 should be 9N2 not 5N2

[@sabirl9232]

I can’t draw the arrows, i don’t understand the direction. Can anyone help me with it?

[@juniyasteffi3790]

your videos r really superb as it really makes us understand

[@Rtfsilky]

cheeyaz lads i am very grateful

[@syazaarshad8302]

Thank so much it really helped me.

[@shahana.]

in combustion isnt the answer always supposed to be negative

[@crieliocriel]

they use the wrong formula.. they do.. reactant - product.. instead of product - reactant.. and they use the wrong standard enthalpy of h2(g) which is zero..

[@Mihindu-vm9wh]

i am struggling with getting intermedate products

[@CFCNoir]

is it just me or is it the other way round? like for 21:58 it says to work out enthalpy change of formation but she’s working out combustion… or am i wrong?

[@physchemwithliz5879]

Hi, combustion data is used to work out enthalpy of formation and formation data is used to work out enthalpy of combustion. Confusing, I know!

[@Rtfsilky]

Jazak Allah. Thank you.

[@launchpadlearn]

You are most welcome! 😊

[@peaChes_s]

I still don't get how the arrows work I thought combustion means arrow pointing downwards?

[@jaleh21]

i have the same question

[@physchemwithliz5879]

The cycle you draw depends on the type of data you're given, rather than what you're asked to calculate 🙂

[@themarschievous]

TYSM THIS VIDEO IS SO HELPFUL!!!

[@earthdoesurvivalcraf]

why is the intermediate at 6:22 "2N(g)" where as at 8:36 its "N2(g)" could u explain why?

[@darkChocol8]

i think the fact that at 6:22 its 2 nitrogen atoms and at 8:36 its a diatomic nitrogen molecule may mean that the have different levels of enthalpy. Maybe 2N has higher enthalpy than N2? I not sure

[@rebeka8806]

How to know in which direction the arrow must be put?

[@vongaimuswinu2326]

Lovely video

[@plodys]

Anyone else notice the oxygens don't balance in the enthalpy change of formation for glucose?

[@lbfosu]

Meeeeeee it had me going crazy...lol that’s what brought me here wanted to be sure I’m not the only one ☺️

[@opiestachio]

Meeee

[@abeerawaseem42]

meeeee

[@abeerawaseem42]

it is correct tho cus glucose is combusted in the presence of 6mols of oxygen so that makes 12 oxygen

[@flyorwalk1743]

I'm having a really big prob with hess law but born haber cycle is simple however this one confuses me too much.

[@nanettesarpong1869]

How did you get 4C+5N2+12H2+10O2 as the intermediate?

[@shellykrypton5611]

Its should be 9N2

[@WhiteRoomBoy]

@@shellykrypton5611 thought it should be 18 cuz 5N2O4

[@kazishahjalal6852]

@@WhiteRoomBoy yeahh you are right

[@epicprobg1876]

16:54 how is it 10 oxygen and not 5?

[@va_rs_ha_]

Thank you so much ♥

[@blackgamerz1268]

Nice for your Understanding

[@simrannahar8262]

incredibly valuable!

[@ambientsoda106]

This is brilliant

[@mohammadfahimakhtar5611]

Thanks, good work.

[@anagomes6587]

So I keep getting 2830 not -2830 am a lil confused coz I got all the other calculations correct

[@ReeganDalli]

Do you know where you went wrong yet?? Its probs a silly mistake

[@elsiemazarura3711]

It should always be delta H negative for combustion reaction because we always lose energy.

[@anagomes6587]

Reegan Dalli it clear was a fat silly mistake, crazy looking back at this now 4 months later and realising this is the least of my worries now haha

[@anagomes6587]

Elsie Mazarura I pretty sure i did products - reactants rather than reactants - products so I got 2830 instead of -2830 thanks!

[@farhaanahmed8924]

@@anagomes6587 Yeah, if you use the formula like me, then that's how it is, I had the same problem and wasted an hour trying to figure out where I went wrong lol.

[@crieliocriel]

you put the wrong standard enthalpy.. it is H2O not H2. 4:30 H2(g) is zero in standard enthalpy..

[@RajitChy22]

16:56 10 N? shouldn't it be 18?

[@jordannemclean6467]

THANK YOU THANK YOU THANK YOU THANK YOU

[@yousufabrar3031]

how do we create that constituent table so confused.......

[@charliebrett7510]

They give it to you in the exam

[@mr.nicktuts653]

Uko juu 😏👍

[@khanimator5674]

after watching this video, I doubt all the knowledge I have

[@zerox00100]

16:09

[@shonib6533]

At 2:16 the products should be replaced with intermediate and the arrows need to shift too

[@weshouldsaveourselves6780]

great vid thanks

[@alexjennings02]

12:13 why is it 9O2 instead of 6O2

[@elsiemazarura3711]

Check the 6Oxygen already found in the glucose molecule

[@Jenika254]

@@elsiemazarura3711 but on the left hand side altoger there is 18 oxygen molecules. So why isn't it 902

[@saraessa7381]

i love you thankyou

[@archie3723]

Cheers hermione

[@yuvlencurpen5865]

Subscribing!!!

[@rojatseven2025]

17:09 I’m sure N2 should be a 9 not a 5

[@nabillrafiin383]

Thank youu

[@gamingwithmo6121]

philadelphia national school is the beast

[@AlchemistAH]

amazed

[@lbfosu]

Is it just me or there is a problem with 3:25 ???

[@aparnakhoptikar1113]

Yes. Wonder where in the reaction oxygen joined them lol

[@sarahsheikh5083]

Combustion gives CO2 and H2O

[@hireshk3013]

Ily

[@lilggs4813]

It do be making sense tho

[@hamzahahmed9951]

What the fuck is an intermediate

[@mazas9713]

Didnt understand shite

[@justformovies956]

R u Indian?

[@justformovies956]

I hate ur British accent but like your video...lol

[@gamingmaniac5611]

i hate you american

[@juanfaguy8640]

@@gamingmaniac5611 I'm not american LMAO

[@khabibconor1566]

@@gamingmaniac5611 I am not America wither

[@s1tiama293]

Her voice is what makes it easier to understand so stop being a hater u prick

[@georgekirby7656]

Thought is was only England that take A-levels, why would you bee watching the video if you weren't doing the course? And if you are doing A-levels, I hardly doubt you would have heard there English speakers during lessons e.c.t?