Chemistry: Post your doubts here!

[ZaqZainab]

I don't like being a p***y who report others behind back and be nice in front of them. change the subject as you said. i though you people owe me an apology but forget it. i am waiting for new doubts....

I would have wanted this topic to get over but just to be clear an apology from me? what for? telling you guys to be done with the argument?

 

[Rockstar RK]

Just write the equation and balance it
Hope it helps
Do u want detailed explanation??!

Yup bro...

 

[Haya Ahmed]

http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s04_qp_1.pdf

Q3

 

[Suchal Riaz]

Yup bro...

2Al + 3O2-->Al2O3 one mole requires 3/2=1.5 moles of O2
2Mg +O2-->MgO one mole required 1/2 moles of O2
P4+ 3O2-->P4O6
4Na + O2 --> 2Na2O one mole required 1/4 moles of O2
so D is the answer.

 

[Suchal Riaz]

just for the record if i was being rude who was the one who started it:

How is it against the Term and Rules ??!.............Many people have a signature like this
Also..there is a better way to ask me to remove it

 

[ZaqZainab]

Yup bro...

A aluminium 4Al + 3O2 → 2Al2O3 now for 1 mole Al 3/4O2
B magnesium 2Mg + O2 →2MgO and 1 mol of Mg 1/2 O2
C phosphorus 4P + 5O2 ---> P4O1 and 1 mole of P 5/4 of O2
D sodium 4Na + O2 ---> 2Na2O and 1 mole of Na 1/4 of O2

 

[Ahmed Aqdam]

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

Q3

Mr of NaN3=65
Moles of NaN3=0.77

Moles of N2=0.77*3/2=1.15
Volume=1.15*24=27.7 dm^3

 

[Rockstar RK]

just for the record if i was being rude who was the one who started it:

Hey bro, will u be available here till 10:00pm IST(Indian Standard Time)..... PLEASE BRO!!!!

 

[Suchal Riaz]

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

Q3

 

[Suchal Riaz]

Hey bro, will u be available here till 10:00pm IST(Indian Standard Time)..... PLEASE BRO!!!!

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

 

[crazytaylorfanXD]

Can someone help me with a few questions from :
JUN 08 QS31
NOV 08 QS 2 , 31
JUN 11 QS 24 , 31

 

[MYLORD]

Mr of NaN3=65
Moles of NaN3=0.77

Moles of N2=0.77*3/2=1.15
Volume=1.15*24=27.7 dm^3

Can u help me with the same year q1

 

[Rockstar RK]

Q25) 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]

Q25) 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

Suchal Riaz pls solve dis 1

 

[crazytaylorfanXD]

http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s08_qp_1.pdf
qs 31


http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_w08_qp_1.pdf
qs 2 , 31

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_qp_11.pdf
qs 24 , 31

 

[Haya Ahmed]

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

Q18 and Q14

 

[ZaqZainab]

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

Q18 and Q14

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

 

[Youssef Tawil]

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

 

[ZaqZainab]

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

Q18 and Q14

q14 A because it is the most electro positive and so it going to draw more negative charges than the other 3 choices will.

 

[Metanoia]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s08_qp_1.pdf
qs 31


http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w08_qp_1.pdf
qs 2 , 31

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_11.pdf
qs 24 , 31

Hi, please include the answers for your respective questions to allow us to reply easier.

s08qp1

Q31. Balance the equations below to see which 1 mol of substances require 2.5 mol of O2
C2H5OH + O2 --> CO2 + H2O
C2H2 + O2 --> CO2 + H2O
CH3CHO + O2 --> CO2 + H2O

w08qp1

Q2


Q31.
Statement 1: Justify the strength properties
Statement 2: Justify the lightweight properties

s11qp11

I have uploaded videos on the s11 paper, clarify again if the explanations don't make sense.