AQA A Level Chemistry Paper 3 7405/3 - 23 Jun 2022 [Exam Chat]

Original post by tuflaaa

which equations do we need to know for the electrode potentials topic?

is it just the lithium battery + alkaline hydrogen-oxygen fuel cell?

currently on chemrevise and the summary sheet says that we don't need to learn all equations but doesn't specify which ones who actually need to know :confused:

I usually watch allery chemistry on youtube, he has all the info for every topic try and watch the video on electrode potential that can answer many of your questions, I mean you could skip the bits that you know already

Reply 22

Original post by tuflaaa

chemrevise has a good summary of them :smile:

PMT also has specific methods so is good too.

Thank you I’ll stick with chemrevise first

Reply 23

TypicalNerd

18

Original post by Doinadddddffff

Guys where can l find all the required practicals

https://chemrevise.files.wordpress.com/2018/04/practical-guide-aqa1.pdf

Here’s the chemrevise summary someone else mentioned. When I find their comment, I’ll rep them.

Reply 24

I really struggle with understanding how fuel cell works can someone summarise all stages please😭

Reply 25

Original post by Doinadddddffff

I really struggle with understanding how fuel cell works can someone summarise all stages please😭

i was using chemrevise and u dont need to know every single stage for aqa chem, but u really need to know the advantages and disadvantages
AND THE EQUATIONS IN ALKALINE CONDITIONS

adva :
more efficient because it transfers more energy to kinetic energy while combustion engines transfer more energy to thermal energy
only waste product is water so no co2 directly released from cell, so does not harm environment and cause problems such as global warming
doesnt need to be recharged as it supplies its own current as h2 and o2 will be continuously supplied

dis :
h2 is highly flammable so its difficult and expensive to store and transport around
.its not fully carbon neutral because co2 is still released in processes such as electrolysis when extracting h2 from methane

equations
4oh- + 2h2 ------> 4e- + 4h20
o2 + 2h2o + 4e- ------> 4oh-
overall :2h2 + o2 -----> 2h2o

hope this helps !

Reply 26

Original post by sunshine11111

i was using chemrevise and u dont need to know every single stage for aqa chem, but u really need to know the advantages and disadvantages
AND THE EQUATIONS IN ALKALINE CONDITIONS

adva :
more efficient because it transfers more energy to kinetic energy while combustion engines transfer more energy to thermal energy
only waste product is water so no co2 directly released from cell, so does not harm environment and cause problems such as global warming
doesnt need to be recharged as it supplies its own current as h2 and o2 will be continuously supplied

dis :
h2 is highly flammable so its difficult and expensive to store and transport around
.its not fully carbon neutral because co2 is still released in processes such as electrolysis when extracting h2 from methane

equations
4oh- + 2h2 ------> 4e- + 4h20
o2 + 2h2o + 4e- ------> 4oh-
overall :2h2 + o2 -----> 2h2o

hope this helps !

Thank you soo muuchhh!

Reply 27

guys u know for practical 4,there isnt really a method, like its just testing in test tubes or am i wrong ?

i feel like we gonna get a method on enthalpy change coz 2019 i think had electrochemistry practical

Reply 28

Original post by sunshine11111

guys u know for practical 4,there isnt really a method, like its just testing in test tubes or am i wrong ?

i feel like we gonna get a method on enthalpy change coz 2019 i think had electrochemistry practical

Yeah you just have to memorise all the equations, colours and ions i think and I would say to have a look at the trends across the periods and groups especially group 7 and they might ask about how reactive the ions are or smth

(edited 1 year ago)

Reply 29

thirtyfour

9

Original post by sunshine11111

guys u know for practical 4,there isnt really a method, like its just testing in test tubes or am i wrong ?

i feel like we gonna get a method on enthalpy change coz 2019 i think had electrochemistry practical

do u think it's worth learning a method for that RP

Reply 30

Original post by thirtyfour

do u think it's worth learning a method for that RP

its actually worth learning a method for all the ones on the advanced

Reply 31

Lucy.may2

12

how do u guys learn methods, using chem revise or yt videos?

Reply 32

Original post by Lucy.may2

how do u guys learn methods, using chem revise or yt videos?

the thing is chemrevise is good,but its way tooo specific, so i feel like watching a vid will help u apply it in exam,coz it wont be exactly the same

Reply 33

neonmozzy

11

what types of questions are likely to come up from transition metals? in P1 they mainly asked about the colours/d orbitals etc so do you think they might ask about isomerism esp as that didn’t come up? also did catalysis come up i can’t remember ??

Reply 34

EsotericMedic

14

I think it could be something related to redox titrations or catalysis (hope it isn't tho)

Original post by neonmozzy

what types of questions are likely to come up from transition metals? in P1 they mainly asked about the colours/d orbitals etc so do you think they might ask about isomerism esp as that didn’t come up? also did catalysis come up i can’t remember ??

Reply 35

Charlie728477282

10

Original post by YoungEmrys

I think it could be something related to redox titrations or catalysis (hope it isn't tho)

wasnt there a redox titration in paper 1 though ? would they really make us do another ??

Reply 36

tuflaaa

6

guys I don't really know what I'm feeling but I'm kinda sad (?) and very disappointed at the same time with the sciences...

all my other subjects have stuck to advanced spec very well - don't know about the other subjects but at least for other ones I do they asked what they said they would ask. Yes questions were still hard but at least I could narrow down my revision.

but for bio and chem (especially chem!) they've literally not stuck to the advanced spec at all (like istg all those synthesis questions yesterday and group 2 and 3 stuff for paper 1 were not low tariff at all) and many people ended up believing (me) that they were going to be low tariff and didn't spend a long time on those topics - WHICH DOES MAKE SENSE? because our year has been affected by Covid so badly - I literally haven't been taught NMR in class :frown:

and I'm so bad at learning stuff by myself.

it just really annoys me that I could end up missing my grade to uni just because of this stupid advanced spec stuff. What is the point of giving us the advanced spec when we have to learn EVERYTHING anyways? :frown:

ps. I'm sorry guys for ranting but I'm just really sad and very very stressed for Thursday and Friday (even more sad as all my other friends have finished Alevels rip)

Reply 37