GCSE Chemistry Revision "Concentration and Reversible Reactions"

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In this video, we start looking at the factors that can change the equilibrium of a reversible reaction. We look at Le Chatelier's principle, focussing on concentration.
This video is based on the AQA spec. If you are following a different exam board then you should check your specification. The Amazon link above is an affiliate link. This provides a small commission which helps to support freesciencelessons. The cost remains the same to you. If you prefer not to use this, you can search Amazon for the Freesciencelessons workbooks.
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[@germaine6305]

this guy and the CGP books are the only thing teaching me at this point

[@kian2135]

Amazing videos, they don't explain this well in school. The revision guide is also very confusing at times, so thanks

[@harrypownall3254]

hahahah everyone watching this the night before the exam

[@JP-yg8lu]

You bet :)

[@pop31774]

he is no joke getting me through this]

[@pacmanpus64]

as soon as love island was done, hopped straight on the videos geez

[@A-bt9nz]

yea me too lol

[@armatejani2870]

Haha

[@laylanpointon-berkowitz6428]

Thank you once again for saving my revision. You're amazing. Keep up the good work Sir.

[@mixedmegamings]

3 periods of 40 minutes each and didnt understand the concept but now i do thanks !

[@spare_mangomilkshakelimits6979]

he does not smile in the end any more

[@alienatedbanana9990]

It's the effect GCSEs have, haha But I've noticed that too! I always used to wait for the smile and now it's no longer there! It breaks my heart :( Bring back the smile!!

[@adequatemuliebrity7516]

@@alienatedbanana9990 lmao same, I always skip to the end to see it but it aint there no more :( XD

[@ameliashandcraftedmemes7888]

69 likes, congratulations!

[@balicebali]

he did

[@phase0400]

Shawn never smiles when talking about the specification. Its very serious stuff.

[@FB-zh5se]

This was so helpful and well-explained, as are all your other videos. Thank you so much Freesciencelessons!

[@Freesciencelessons]

Thank you. I appreciate your comment.

[@sanjaymarcus530]

I have my chemistry mock 3 tommorow and these videos are soo helpful

[@alisa-tinebilal4740]

Hi sir, thank you so much for your incredible videos. I don't know how to appreciate all your fantastic work! literally, your videos are my best revision resources. I have been watching your videos all the time every time I have a test, revision or just for studying! thank you so much, for all triple content- biology, chemistry and physics. your videos help me revise a lot as revision is a really big struggle for me. You are just brilliant sir, your videos are spot on! **I had a question related to this video: why when the N2O4 concentration decrease more 2NO2 was reacted but when you increased the concentartion of N204, more 2N02 was still reacted? isn't it supposed to decrease because due to the Lechatelier's principle the reaction responds to counteract the change?** I am a bit confused here, I usually just watch your videos without asking a question but I need help with this one if possible. I will be waiting for your help sir! seriously, thank you very much sir! I don't know how else to appreciate your work, they are seriously helping me so much! Thank you very much sir! Best regards, Alisa

[@Freesciencelessons]

Hi. Sorry for the late reply. Was there more to this question eg a graph? As it stands, I think I'd need more information.

[@alisa-tinebilal4740]

@@Freesciencelessons Hello sir, It's completely fine. Thank you very much. I am not sure with the third example, why did both compounds increase? Isn't one of the compounds supposed to increase and the other one decrease? I am speaking about the 3rd equation. They both increase. I thought that if one increases the other one counteracts the change. I hope this is clearer now. Thank you

[@xpumapvpsshorts5734]

tad late but when you increase the concentration of N2O4 there is more2NO2 FORMED not reacted, and so the equilibrium shifts to the left.

[@mvoo44]

one of my most hated topics in science

[@hat_crab4600]

honestly at this point id rather just have home learning all the time because first of all, i learned way more when i was at home that in school, and also the teacher could just put on a video like this and then have us do some worksheets to practise

[@MattyGGamer]

These videos are extremely useful. Your an absolute legend for making these.

[@invincibleam17]

Im so thankful today is the last day ill ever hear about Le Chatelier Principle. I literally never understood it, and hope it doesn't come up in my exam today.

[@fireemperorzuko8756]

Ur doing ur GCSEs today??

[@invincibleam17]

@@fireemperorzuko8756 i had to resit mine because I received grades that we're lower than my expectations.

[@sonicgamer178]

@@invincibleam17 dang. My GCSEs were straight up cancelled

[@svtcafe6526]

thank you

[@SophiaLawrance]

ur videos have saved my grades thank u

[@diyaash4918]

beautifully explained lad

[@isobellaux9177]

At the second question (2:28), I understand that because you decreased the concentration of N2O4, it will make more N2O4 to counteract the change, but you haven’t said which side the reaction shifts to? Does it shift to the right because it makes more N2O4? Or does it shift to the left because these reactants are what are needed to make more N2O4?

[@hithere-oi9cj]

the left because it counteracts the change. n204 cant form itself

[@haruunhassan8516]

any upcoming new videos for this years gcse?

[@celeryman109]

How can we add more NO2 (to increase concentration) if equilibriums of reversible reactions only occur in closed systems (therefore no reactants can be added)?

[@yay1054]

Celery Man I think he is trying to explain that if you add something to a closed system then the reaction is no longer at equilibrium so it will try to reach equilibrium again.

[@hithere-oi9cj]

you dont add it. the conc of the no2 increases because n204 forms more of it

[@louissilsby8819]

I have been so confused on this and it seems so easy no

[@leonhardolaye-felix8811]

Wait so where does the equilibrium move. You only told us which reactant increases

[@Master_Bater69]

It moves to the left or right depending on the increase/decrease of pressure. Check out his video on reversible reactions. It has a brief overview of equilibria

[@Celeste_51]

2:54 for this question does increasing the concentration favor the forwards or backwards reaction? 2:20 I am wondering this too

[@MR-uo6xy]

when increasing the concentration on one side the other side will be favoured.

[@mohammadmoniruzzaman9337]

Sir, your videos are really easily understandable that actually helps me before my exam.😊

[@elizabethwright568]

Good luck everyone for tmrw

[@blazeuchiha2314]

2:28 can someone please explain this because i don't understand it properly

[@Phosphoenoylpyruvate]

Decreasing the concentration of n2o4 decreases the rate of reaction of the backwards reaction so the reaction will no longer be at equilibrium. More 2no2 will react to try to raise the concentration of n2o4 so the rate of reaction(backwards) increases to restore equilibrium

[@Phosphoenoylpyruvate]

Idk I could be wrong

[@FlixRacing]

Thank you❤

[@user-tg1zf6ow4o]

Just wondering will the equilibrium basically shift to the side with with the lower concentration so it increases?

[@xpumapvpsshorts5734]

yes

[@mrnothere9542]

so we have 2NO2 and n204 and on the right hand side it decreases but on the left it increases. How does it increase on the left and decreases on the right?

[@basmalawessam2488]

youre a legend sir

[@danielesfen4801]

nice video, thank you m8

[@riyadhul-hoque6851]

Thank you.

[@harkus8831]

Thank you very much.

[@s1nan_ss]

Do we need to remember that it's called 'Le Chatelier's Princliple'?

[@Freesciencelessons]

That's in the spec so I'd recommend learning it.

[@s1nan_ss]

@@Freesciencelessons okay thanks

[@l-ja5597]

Thank you!

[@JohnSmith-ef4rc]

Great knowledge given and may God bless you for your endeavours - however, it doesn't help that I saw a rather inappropriate ad just before this video.

[@dreamer5769]

im a bit confused... is a reversible reaction always at equilibrium unless conditions are changed? like is it automatically at equilibrium unless otherwise stated?

[@yay1054]

I think it’s only at equilibrium when it’s in a sealed container as none of the reactants and products can escape.

[@hithere-oi9cj]

yeah pretty much

[@khadija2739]

wait im confused...why does it want to go back to equilibrium?

[@khattakjarir3399]

innit

[@antonia5315]

does anything happen if you decrease the concentration of the reactants?

[@Name7.62]

If we decrease the concentration of reactants the system is no longer at equilibrium and it acts to counteract this change. Therefore equilibrium will shift to the left and more of the products will react to form the reactants (increase conc of reactants), until equilibrium is reached again. Just out of curiosity are you in y10 or 11 because we studied this at the start of year 11?

[@azwahaider4383]

@@Name7.62 will the equilibrium not shift to the right?

[@nolimitdennis8730]

Name 1 so how come its the same when you increase the concentration, shouldnt it be the opposite

[@antonia5315]

Name 1 im in year 11, and thank uu

[@stormblaster6781]

More of the products will react to produce more of the reactants till point of equilibrium is reached

[@musclecowman6345]

Thank you so much, i cant explain to you how much this helped underdtand this topic more

[@Aisha-gd6dq]

Thank u

[@gorgeousss9014]

I hope I pass my chem test on Monday 🤞🏽

[@junebug2299]

How was it? Xx

[@wdlwunde2120]

i love you

[@rae4days207]

is this vid only for triple

[@charrot3723]

Higher combined

[@atiarimi5994]

Also, doesn't the reactant need to react with something in order to produce the product

[@faizanahmad-bw9uw]

NO2 +NO2

[@eleanorsamspg5425]

So you dont need to know this if you do foundation?

[@greyweather7768]

Eleanor Samspg Yeh

[@lilstjimmy]

my guy

[@tomcox3441]

Night before chemistry paper 2 2023 😭😭

[@kishanmistri]

Night before chem paper 2 2022 😭🙏

[@ellasorchid]

2023 🙏

[@louissilsby8819]

now*

[@MrBlazingbanana]

what if less 2NO2 someone clutch up exam in 12 hours thanks

[@deviant7100]

nobody clutched up :(

[@Name7.62]

I will clutch for you my friend, a bit late I know but it will help with my revision, so if we decrease the concentration of N02 the system is no longer at equilibrium. Therefore more N2O4 (which is at a higher conc) will react to form N02 until equilibrium is reached again. Thus equilibrium will shift to the left (more reactants formed).

[@atiarimi5994]

At 1:20 you said N2O4 can also react to form NO2, why wouldn't it form 2NO2

[@Ryan-1704]

You are correct but he is just referring to the fact that the molecule NO2 is formed. In that reaction, there would be 2 separate molecules of NO2

[@TofiYouTube]

Anyone else watching on the way to school on exam day? 😅

[@user-fh6lx1fb2g]

goodluck to myself tomorrow.

[@r0wen]

Bro I gotta go bed and it’s tomorrow 👹

[@yasuaro]

Thank you so much

[@ivanakona392]

thank you