Chemistry: Post your doubts here!

[Youssef Tawil]

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http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s13_qp_13.pdf
can someone explain q8 19 22 28 35 37 39

Q8: you know B and C are wrong because they contain a OH group so will form hydrogen bonds, A is also wrong as NH2 can form hydrogen bonds leaving D which is the correct answer
Q19: it asks for a transition element COMPOUND so it is vanadium pentoxide which is used in the contact process therefore it is B
Q28: there has to be a attachment to 2 adjacent carbons so its C

 

[_Ahmad]

PLEASE HELP!!

Q10,11,18,32,34 from
http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s05_qp_1.pdf
http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s05_ms_1.pdf

and

Q2,10,15,32,34,36,38 from
http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s06_qp_1.pdf
http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s06_ms_1.pdf

 

[♣♠ Magnanimous ♣♠]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s13_qp_13.pdf
can someone explain q8 19 22 28 35 37 39

well some of them are solved by youseef and others i am unsure! I hope you got this question and yes the answer is D

 

[GCE As and a level]

ZaqZainab THNX

 

[Jelleh Belleh]

Does anyone know whether or not it's okay to give our answers in standard form in the calculation parts of practicals?

 

[doremon]

yes its ok. but they prefer 3 s.f.

Does anyone know whether or not it's okay to give our answers in standard form in the calculation parts of practicals?

 

[Jelleh Belleh]

yes its ok. but they prefer 3 s.f.

Okay, thank you.

 

[Princess Raven]

PLEASE HELP!!

Q10,11,18,32,34 from
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s05_qp_1.pdf
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s05_ms_1.pdf

and

Q2,10,15,32,34,36,38 from
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s06_qp_1.pdf
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s06_ms_1.pdf

Q10) it shifts towards the right since it's exothermic and pressure also increases so B is the answer
Q11) at first ch3oh is produced swiftly but then gradually it decreases uve just to memorize this graph for products forming
Q18)NH4X > CO(NH2)2 if since it has both n and c in the product it can either be A or B.. a is correct because when u write the equation it will be balanced using A and not balanced using B
32) okay so I don't get 1 or 3 but 2 is surely wrong because pressure is directly proportional to temp so It increases so of 2 is wrong the answer must be D
34) rate of rxn of exp2 was less so it could be 2 for sure and also 1 makes sense less p means reaction shifts towards the left so less product forms

S06
2) memorize it's 3 it could be 35 35 or 37 37 or 35 37
10) I'll write it and post the explanation for u
15) high temp so al2cl6 forms the correct structure is A always the arrow is towards al
32) u need 1 so get the energy of Na(g) and since it's Na+ u also need 2.. 3 is irrelevant so B is the answer
34) 1 is ionic and thus conducts electricity in liquid state so 1 is wrong so the answer is C
36) 3 is wrong Because the oxidation of hydrogen remains +1 so B is the answer
38) got no clue

 

[Princess Raven]

PLEASE HELP!!

Q10,11,18,32,34 from
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s05_qp_1.pdf
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s05_ms_1.pdf

and

Q2,10,15,32,34,36,38 from
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s06_qp_1.pdf
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s06_ms_1.pdf

Question 10 explanation

 

[Browny]

http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s06_qp_1.pdf
Can anybody please explain questions 22, 31? Ans are A and B respectively.

In 22 why can't B be the correct answer and in 31 can you explain the 1 statement.
Also in a reaction pathway involving a intermediate is the first stage Ea always greater than the second stage Ea?

http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_w06_qp_1.pdf
Can anybody please explain questions 5, 19? Ans are B and B respectively.

THANKS IN ADVANCE!

 

[Jelleh Belleh]

One more question, is it recommended to finish up all the practical work first, and then complete calculation questions? Or do both as they come?

 

[Browny]

One more question, is it recommended to finish up all the practical work first, and then complete calculation questions? Or do both as they come?

Do both as they come I think as then you are in touch with the question and you don't have to keep on rereading the questions.

 

[Browny]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s06_qp_1.pdf
Can anybody please explain questions 22, 31? Ans are A and B respectively.

In 22 why can't B be the correct answer and in 31 can you explain the 1 statement.
Also in a reaction pathway involving a intermediate is the first stage Ea always greater than the second stage Ea?

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w06_qp_1.pdf
Can anybody please explain questions 19? Ans is B.

THANKS IN ADVANCE!

 

[doremon]

can somebody give me some tips and tricks for tomorrow?

 

[unkidd]

and the practical which has a high probability of coming

 

[IGCSE13]

http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s05_qp_3.pdf. Can someone explain q1 c to f please

 

[student1415]

thank you

it's simple!
see 39) when there is an OH the reaction can occur with sodium metal and that is given in the book which means tatement 1 is CORRECT!
statement 3) overall molecular formula is C5H12O4 so it cannot be CH3O which means this is wrong and due to this statement 2 is also eliminated so answer is D

 

[student1415]

thank you

28)
1 u know is right
2) when two ethane radicals combine
3) when combination of ethane radical is chlorinated

37)
Remember the termination step. Two free radicals join to form a molecule. Break this molecule CH3CHCl-CHClCH3 into this CH3*CHCl and *CHClCH3. These are two free radicals formed in the propagation step. Whenever these questions come. Break the central bond and check if two free radicals are formed.

39)
♣♠ Magnanimous ♣♠

 

[Thought blocker]

thank you

np

 

[_Ahmad]

PLEASE can anyone explain these questions.

Q1,9,32,36,37 from
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w06_qp_1.pdf
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w06_ms_1.pdf

Q20,26,33,34,40 from
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s07_qp_1.pdf
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s07_ms_1.pdf