Chemistry: Post your doubts here!

[daisyy]

hey can anyone please help me in Question number 20 http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s06_qp_1.pdf Thank uu!

 

[daisyy]

I also need help in question number 12 Oct/Nov 2005!! I appreciate your help

 

[felicia tan]

The cracking of a single hydrocarbon molecule, CnH2n+2, produces two hydrocarbon molecules
only. Each hydrocarbon product contains the same number of carbon atoms in one molecule.
Each hydrocarbon product has non-cyclic structural isomers.
What is the value of n?
A 4 B 6 C 8 D 9
please help!

 

[strangerss]

When there's a ring, there can't be a cis-trans isomer.
13. Construct a balanced equation and use mole ratios.

why there can't be a cis-trans isomer in a ring? I did construct a balanced equation and got the mole ratio of AL2O3 to HCL 1:6 but my final answer was 60 instead of 30

 

[h4rriet]

why there can't be a cis-trans isomer in a ring? I did construct a balanced equation and got the mole ratio of AL2O3 to HCL 1:6 but my final answer was 60 instead of 30

You have to construct two balanced equations. You forget Al + 3/4O2 -> 1/2Al2O3 + H2O and use the mole ratio from this equation for the other equation.

 

[A star]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w12_qp_11.pdf
Q4 , Q15 ( which gas O2 or NO2) n Q17 A star or daredevil Jiyad Ahsan syed1995



http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w12_qp_13.pdf
Q5 Q17 n Q36( sum1 explain the Kp part)



http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_11.pdf
Q38 Q36( why backward reaction increases) Q28 Q21



http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_11.pdf
Q8 Q13(i get A) Q22

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_12.pdf
Q28

Q4 (2times bond energy of N=O) - (2*bondenergy of N2+2*bondenergy of O2)
Q15 both are released
Q17D

 

[strangerss]

thank

You have to construct two balanced equations. You forget Al + 3/4O2 -> 1/2Al2O3 + H2O and use the mole ratio from this equation for the other equation.

thank you

 

[strangerss]

alsalum allyakom
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s10_qp_11.pdf in question 21 was is the answer 3 and not 4? and inhttp://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Chemistry%20(9701)/9701_w11_qp_11.pdf can someone plaese explain Q27?

 

[A star]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w12_qp_11.pdf
Q4 , Q15 ( which gas O2 or NO2) n Q17 A star or daredevil Jiyad Ahsan syed1995



http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w12_qp_13.pdf
Q5 Q17 n Q36( sum1 explain the Kp part)



http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_11.pdf
Q38 Q36( why backward reaction increases) Q28 Q21



http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_11.pdf
Q8 Q13(i get A) Q22

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_12.pdf
Q28

Q5 its B as delta h can be both depending on type of solution that reacts and atomisation is positive
Q36B as SiO2 is inslouable and p4)10 is acidic so will change

 

[strangerss]

You have to construct two balanced equations. You forget Al + 3/4O2 -> 1/2Al2O3 + H2O and use the mole ratio from this equation for the other equation.

I don't think there's H2O right!

 

[Alice123]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_12.pdf
Q11 Jiyad Ahsan

 

[6Astarstudent]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_13.pdf
Q11

Answer is B, activation too high

A: irrelevant, state only determines whether reaction will occur or not, and rate
C: the bond that is broken is N=N not triple bond
D: exothermic reactions occur easily, unless high EA
so B is correct answer

 

[Alice123]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w12_qp_11.pdf
Q11 n Q15

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w12_qp_13.pdf
Q5
Jiyad Ahsan

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_11.pdf
Q21, Q28, Q38 Q36


http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s12_qp_12.pdf
Q28

 

[Alice123]

Answer is B, activation too high

A: irrelevant, state only determines whether reaction will occur or not, and rate
C: the bond that is broken is N=N not triple bond
D: exothermic reactions occur easily, unless high EA
so B is correct answer

im sorry.. it was my mistake.. i had prob wid var12 nt 13... neways thanks

 

[h4rriet]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w12_qp_13.pdf
Q5

For 5, use bonds broken - bonds formed.

 

[Alice123]

For 5, use bonds broken - bonds formed.

i did.. 2900-2400

 

[h4rriet]

i did.. 2900-2400

Your bonds formed is wrong.

 

[Alice123]

Your bonds formed is wrong.

so cud u please show the correct one??

 

[h4rriet]

so cud u please show the correct one??

(2 x H-O) + (4 x C=O).

 

[Saad (سعد)]

As-Salaamu 'alaykum.

Q7 P12 M/J/12, and Q11 P13 M/J/12, please.

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_12.pdf
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_13.pdf