Chemistry: Post your doubts here!

[salvatore]

http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_w08_qp_4.pdf
Could someone please help me with qn no 2(e)? I don't understand why the order with respect to H+ is 0

 

[Thought blocker]

I suck at organic :/
3di) how in ms they got Ba as 81.1 ? :/
Whole question 4 and 5 :/
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_22.pdf

ZaqZainab

 

[ZaqZainab]

I suck at organic :/
3di) how in ms they got Ba as 81.1 ? :/
Whole question 4 and 5 :/
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_22.pdf

ZaqZainab

really?
100-18.9=81.1

 

[Thought blocker]

really?
100-18.9=81.1

:''( I just start chem few days back

 

[ZaqZainab]

I suck at organic :/
3di) how in ms they got Ba as 81.1 ? :/
Whole question 4 and 5 :/
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_22.pdf

ZaqZainab

even i suck at organic
Question 4 ?it isn't aren't organic the ms says it all perfectly what the confusion?
wait i will need to do 5 myself

 

[Thought blocker]

even i suck at organic
Question 4 ?it isn't aren't organic the ms says it all perfectly what the confusion?
wait i will upload a pic for 5

Explain in detail plz, Idk anything in this quest. :'(

 

[daredevil]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w08_qp_4.pdf
Could someone please help me with qn no 2(e)? I don't understand why the order with respect to H+ is 0

w.r.t. H2O2 :
0.70/.05 = 1.4/1.0
7/5 = 7/5

w.r.t. H+ :
if we consider the conc of H2O2 first and compare it with rate:
0.09/0.05 = 1.8/1.0
9/5 = 9/5

it shows that the rate is changing just because of H2O2 .... which means that however much the conc of H+ changes, it won't have any effect on the rate of reaction. so wrt H+ the order of reaction is 0

 

[ZaqZainab]

Explain in detail plz, Idk anything in this quest. :'(

Okay so i just did 5 there isn't anything up with it all you have to do it study from the course book

 

[Thought blocker]

k

Okay so i just did 5 there isn't anything up with it all you have to do it study from the course book

 

[ZaqZainab]

k

 

[Thought blocker]

ty

 

[Abdel Moniem]

http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s09_qp_2.pdf
Question 4bii

 

[immie.rose]

I´ve already answered this question a few times... Anyways. Here what you should be careful with is the accuracy. Maintain it with 3sf. So once you divide by the smallest number and get 1 : 1.33: 1.16 ratio you just have to convert these numbers into integers. You do it through trial and error until you get all integers. If you times everything by 6 you get an integer (or atleast really close to it).

Hope it helps.

sure helped! THANK YOU!!

 

[immie.rose]

I will follow through the question from beginning to let you know how examiner give you hints.

pattern:
-(information)
the deduction we can make from information

the alcohol will oxidise to produce aldehyde and then will produce carboxyllic acid. as a single compound is formed, both carboxylic acid from ester and oxidised form alcohol are same. the only option we are left with is ethyl ethanoate. which will hydrolyse to ethanol and ethanoic acid. ethanol will then oxidise to ethanal. ethanal will oxidise to ethanoic acid. as the test for C=O and CHO are negative there is no aldehyde. the only thing left is ethanoic acid.

i hope it clears the confusion and helps in reaching conclusions in similar questions.
good luck for the papers ​

Could you pls pls explain a bit further as to why it can't be methyl ethanoate, Or propyl ethanoate, hence leaving ethyl ethanoate as the only option? thanks!

 

[AbbbbY]

Um for silicon chlorides reaction with water, do we write Si(OH)4 as the product, or SiO2,?

They're both acceptable, but the preferred product is SiO2

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s09_qp_2.pdf
Question 4bii

C = CH2(OH)CH(OH)COOH
E = CH3COO-

C+E = esterification. CH2(OOCCH3)CH(OOCCH3)COOH. Another way of writing this is CH2(OCOCH3)CH(OCOCH3)COOH but this OCO shiz always confuses me so I stick to the OOC usage.

 

[WaqarAhmedJamali]

this question came in to our mock exam

 

[loveyuan]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s13_qp_13.pdf

question no 14 .
Answer C. Q only
It is because the AgCl is insoluble in NH3 so it's solubility suppose to be 0 ?

Question no 18
Answer A. CNO-

Question no 28
answer C

Thank you in advance

 

[Snowysangel]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s13_qp_13.pdf

question no 14 .
Answer C. Q only
It is because the AgCl is insoluble in NH3 so it's solubility suppose to be 0 ?

Question no 18
Answer A. CNO-

Question no 28
answer C

Thank you in advance

I though chlorides were soluble in ammonia and that upsides weren't ..

 

[loveyuan]

I though chlorides were soluble in ammonia and that upsides weren't ..

Oh yea. Thanks !

 

[Snowysangel]

Oh yea. Thanks !

Haha sorry I meant iodides...autocorrect -.-