Chemistry: Post your doubts here!

[ZaqZainab]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s13_qp_13.pdf
Number 18??? Answer is A
anyone please?

ammonium cyanate has ammonia and cynate ions
we know ammonium is NH4+ we are left with CON-
CO(NH2)2

 

[Snowysangel]

can u help me solve this
View attachment 45138 ans is c

Ally PV=nRT where n= 1/18

 

[Ahmed Aqdam]

Can u help me with the same year q1

Moles of H2=0.5
Atoms in one mole=2*0.5*6.02*10^23 (No need to multiply 6.02*10^23 i every step as it is same, just find the ratio)
So here atoms=1

A: 0.5*3=1.5
B: 0.5*5=2.5
C: 1*1=1
D: 1/6*3=0.5

So C has same no of atoms.

 

[NIM]

guyzz need help!!!
http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s07_qp_1.pdf
1, 18, 34
http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_w06_qp_1.pdf
3, 5 (why cant it be D), 11, 14, 21, 37
http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s06_qp_1.pdf
1, 3, 10

 

[Metanoia]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s04_qp_1.pdf

Q18 and Q14

s04qp1

Q14. Al3+ is most polarising. Highest charge density will be most polarising (big charge/small radius)

Q18. Use mole calcualtions to solve the amount of products, basing on 58.5 kg of NaCl

2NaCl + 2H2O --> H2 + Cl2 + 2NaOH

 

[NIM]

http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s04_qp_1.pdf
9, 37 (i didnt get the 2nd and 3rd statement as only one reaction can take place)

 

[Haya Ahmed]

http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_w04_qp_1.pdf
Q4

 

[Metanoia]

guyzz need help!!!
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s07_qp_1.pdf
1, 18, 34
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w06_qp_1.pdf
3, 5 (why cant it be D), 11, 14, 21, 37
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s06_qp_1.pdf
1, 3, 10

Hi, please do include the answers to your questions.

s07qp1

Q1. relative mass = 1/5 x 10 + 4/5 x 11 = 10.8

Q18. alkali gas is NH3. Fertiliser is NH4NO3. Empirical formula is N2H4O3

Q34. For mercury on right side to rise, the X flask create a higher pressure than before.
Statement 1: (True) Increase temp shift eqm right, more gases created, higher pressure created by X than N2 on right
Statement 2: (False) Increase temp shift eqm left, same amount of gases, same amount of pressure created in X compared to N2 on right.
Statement 3: (False) Both left and right experiences the same increase in pressure (just like statement 2).

w06qp1

Q3.
P is option A
Ca is option B
Kr is option D
So that leaves element X as option C.

Q5. Pi bond is sideway overlapping of electron orbitals.

Q11.



Q14. This is an often set question.

Group II nitrates decompose based on the equation below:

2 X(NO3)2 (s) --> 2 XO (s) + 4 NO2 (g) +O2(g)

Mass of XO = 1.71g
Moles of XO = 1.71/ (Mr of X + 16)

Mass of X(NO3)2 = 5 g
Moles of X(NO3)2 = 5/(Mr of X + 124)

since moles of X(NO3)2 = moles of XO
5/(Mr of X + 124) = 1.71/ (Mr of X + 16)

Solve for Mr of X.


Q21
This is a bit tedious, you need to draw and figure out the number of structural isomers for the following halogenalkanes.
C2H5Cl (1 isomer)
C2H4Cl2 (2 isomers)
C2H3Cl3 (2 isomers)
C2H2Cl4 (2 isomers)

Q37. Substance 2 will not spilt into two organic products. So that means only statement 1 is correct.
Cleave the C=C bonds of substance 1. The carbons at 1 o'clock and 6 o'clock would form ketones.

s06qp1

Q1. since 2 moles of NaOH reacts with 1 mole of N2O4

Moles of NaOH required = 0.04
Volume of NaOH required = moles/conc = 0.04/0.5 = 0.08 dm^3 = 80 cm^3

Q3. N3- : 10 electrons
1s2 2s2 2p6

Q10.

 

[GCE As and a level]

Hi, please do include the answers to your questions.

s07qp1

Q1. relative mass = 1/5 x 10 + 4/5 x 11 = 10.8

Q18. alkali gas is NH3. Fertiliser is NH4NO3. Empirical formula is N2H4O3

Q34. For mercury on right side to rise, the X flask create a higher pressure than before.
Statement 1: (True) Increase temp shift eqm right, more gases created, higher pressure created by X than N2 on right
Statement 2: (False) Increase temp shift eqm left, same amount of gases, same amount of pressure created in X compared to N2 on right.
Statement 3: (False) Both left and right experiences the same increase in pressure (just like statement 2).

To wat time r u available today,sir

 

[Rockstar RK]

When heated with chlorine, the hydrocarbon 2,2-dimethylbutane undergoes free radical
substitution.
In a propagation step the free radical X• is formed.
2,2-dimethylbutane + Cl● → X● + HCl

How many different forms of X• are possible?
A 1 B 2 C 3 D 4

 

[GCE As and a level]

I will try but i think this community has more harmony and peace without me.

No we are not ....... We are NOT enemies man ......And u should not be that much sensitive
PERSONALLY...I forgive u
and believe me mis understanding happened between all of us

Bro, let the dogs bark at the elephant.... Elephant will always swagger and poor dogs will bark...

This is so rude,But as u wish we will ignore u

 

[GCE As and a level]

When heated with chlorine, the hydrocarbon 2,2-dimethylbutane undergoes free radical
substitution.
In a propagation step the free radical X• is formed.
2,2-dimethylbutane + Cl● → X● + HCl

How many different forms of X• are possible?
A 1 B 2 C 3 D 4

U dont deserve that but i will answer
Is the answer C??

 

[Rockstar RK]

2NaCl+2H2O----> Cl2+H2+ 2NaOH
Mr of NaCl=58.5
Mr of NaOH=40
Mr of Cl2=71
Mr of H2=2
Moles of NaCl=1
so moles of Cl2=0.5
H2 is 0.5
and
NaOH is 1

mass of Cl2=35.5
mass of H2=1
by now we know the answer is A
mass of NaOH is 40

When heated with chlorine, the hydrocarbon 2,2-dimethylbutane undergoes free radical
substitution.
In a propagation step the free radical X• is formed.
2,2-dimethylbutane + Cl● → X● + HCl

How many different forms of X• are possible?
A 1 B 2 C 3 D 4

 

[Rockstar RK]

U dont deserve that but i will answer
Is the answer C??

Did I ask u???

 

[ZaqZainab]

U dont deserve that but i will answer
Is the answer C??

Please get over it

 

[Love Islam]

When heated with chlorine, the hydrocarbon 2,2-dimethylbutane undergoes free radical
substitution.
In a propagation step the free radical X• is formed.
2,2-dimethylbutane + Cl● → X● + HCl

How many different forms of X• are possible?
A 1 B 2 C 3 D 4

The answer is C, As there are 3 possibilities 1. CH3* 2. CH3CH2* 3. CH* (All 3 CH3* are one possibility!)

 

[GCE As and a level]

Did I ask u???

Shame on u
U asked on this thread and i am a member here
Refer to : https://www.xtremepapers.com/community/threads/chemistry-post-your-doubts-here.9859/page-509

 

[Suchal Riaz]

Did I ask u???

wait a moment i am asnwering it. wait.

 

[GCE As and a level]

Please get over it

??!!

 

[Rockstar RK]

No we are not ....... We are NOT enemies man ......And u should not be that much sensitive
PERSONALLY...I forgive u
and believe me mis understanding happened between all of us

This is so rude,But as u wish we will ignore u

I gave Suchal Riaz an idiomatic example

Shame on u
U asked on this thread and i am a member here
Refer to : https://www.xtremepapers.com/community/threads/chemistry-post-your-doubts-here.9859/page-509

U are not ma family member that u should have shame on me!!!