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IAL Edexcel A2 Chemistry Unit 6 (Old syllabus)

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Yes hahaha
Original post by ree.x09
Lmao your username 😂
Are you from bd?
Guys help

K so this question is from January 2018, Unit 4.
For Ethanoic acid, Pka=4.76. The pH of a solution of ethanoic acid with a concentration of 1×10^-10 mol dm^-3 is approximately :
A. 5.2
B. 7.0
C. 7.4
D. 15

The answer is B but i keep getting C no matter how I do it
I think it's because ethanoic acid is a weak acid so partial dissociation occurs and it's neutral
Original post by Erica.kh
Guys help

K so this question is from January 2018, Unit 4.
For Ethanoic acid, Pka=4.76. The pH of a solution of ethanoic acid with a concentration of 1×10^-10 mol dm^-3 is approximately :
A. 5.2
B. 7.0
C. 7.4
D. 15

The answer is B but i keep getting C no matter how I do it
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Nabs78
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Original post by Erica.kh
Guys help

K so this question is from January 2018, Unit 4.
For Ethanoic acid, Pka=4.76. The pH of a solution of ethanoic acid with a concentration of 1×10^-10 mol dm^-3 is approximately :
A. 5.2
B. 7.0
C. 7.4
D. 15

The answer is B but i keep getting C no matter how I do it

Gosh I spent like an hour on this question and this is what I came up with.
When u calculate using the assumption that no [H+] from water is ionized then u can use the standard idea and equation we use which is Ka=X^2/{CH4COOH].
When u apply this equation to the question u get 7.4, however if u dont assume no H+ came from water then the answer would be slightly more acidic due to the slight increase in H+ in the solution, from water.
In this case the next lowest ph is 7 which is more accurate as then u have also taken into consideration the [H+] from dissociation of water which also occurs, that in normal questions we assume hasn't occurred.

This is what I think they are implying on as thats what the mark scheme says too.
Original post by Erica.kh
Guys help

K so this question is from January 2018, Unit 4.
For Ethanoic acid, Pka=4.76. The pH of a solution of ethanoic acid with a concentration of 1×10^-10 mol dm^-3 is approximately :
A. 5.2
B. 7.0
C. 7.4
D. 15

The answer is B but i keep getting C no matter how I do it

Simply you can't get pH greater than 7 if you have acid
Original post by ree.x09
I needed help with a problem. But it’s solved now! :smile:) Thanks anyway!


Your welcome :smile:
why is nichrome wire dipped in HCl?
Original post by Starzzz
why is nichrome wire dipped in HCl?

Flame test 🔥

Nichrome wire is dipped in concentrated HCl and then heated strongly to clean the wire. Then dipped in the acid again to moisten it then dipped into the sample/salt to pick up some of it, then the wire is held in the clear part of a HOT/ROARING flame and observe the color.
Anyone chem unit 6 oct 2018 examiner report please??
Original post by yeswhynot76
Anyone chem unit 6 oct 2018 examiner report please??


Not found
Original post by Keka Ferdousi
I think it's because ethanoic acid is a weak acid so partial dissociation occurs and it's neutral


Original post by Nabs78
Gosh I spent like an hour on this question and this is what I came up with.
When u calculate using the assumption that no [H+] from water is ionized then u can use the standard idea and equation we use which is Ka=X^2/{CH4COOH].
When u apply this equation to the question u get 7.4, however if u dont assume no H+ came from water then the answer would be slightly more acidic due to the slight increase in H+ in the solution, from water.
In this case the next lowest ph is 7 which is more accurate as then u have also taken into consideration the [H+] from dissociation of water which also occurs, that in normal questions we assume hasn't occurred.

This is what I think they are implying on as thats what the mark scheme says too.


Original post by CuriosityYay
Simply you can't get pH greater than 7 if you have acid


Thanks guys !! That's probably what they meant cuz the mark scheme says something about taking H+ ions from water into consideration
can someone help me solve this unit 5 chem question in the jan 2014 wcho paper
its question 21 part 4
Original post by lavacake
can someone help me solve this unit 5 chem question in the jan 2014 wcho paper
its question 21 part 4


part 4?
https://qualifications.pearson.com/content/dam/pdf/International%20Advanced%20Level/Chemistry/2013/Exam%20materials/WCH05_01_que_20140121.pdf
oops,21 b part iv)
Original post by CuriosityYay
Original post by lavacake
oops,21 b part iv)

Page 10
https://qualifications.pearson.com/content/dam/pdf/International%20Advanced%20Level/Chemistry/2013/Exam%20materials/WCH05_01_msc_20140306.pdf
yeah ive seen it but I don't get why its not done the usual way starting form the mno4- moles?

Original post by CuriosityYay
IMG_4880.JPGIMG_4879.JPG Hey guys I had a question from physics unit 6.Why did we multiply the length with 4?
Original post by Keka Ferdousi
IMG_4880.JPGIMG_4879.JPG Hey guys I had a question from physics unit 6.Why did we multiply the length with 4?


This is a chemistry thread bucko
Lol sorry guys I posted this in the wrong thread
Original post by KSaRa
Does anyone have any suggestions for which areas the paper might focus on?


#learn color of transition metals and the ligand
#learn methods of purification and separation
#Redox equations

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