Chemistry: Post your doubts here!

[Princess1997]

Where can i find june and nov 2001 question papers

 

[Suchal Riaz]

GUYSSSS. Gotta help me with this, PLEASEEE. hahahaha
Must be very easy for you guys!
Anyways, okay.
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w13_qp_13.pdf
Q27 (C)

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w13_qp_12.pdf
Q8 (D) [ i guess all these answers correctly, but i dont understand why ]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w11_qp_12.pdf
Q24 (B) , Q26 (A), Q30 (A)

THANK YOU SO SO MUCHHHHHH!! please help

the same questions are asked again and again.
27:
the alcohol is tertiary and have a chiral carbon with least number of carbons: so chiral carbon has one CH3 one OH one C2H5 and one C3H7 attached to it. this is the only way to make the n smallest and still have a teriary alcohol with chiral carbon
8:density depends on Mr. the average Mr of D looks high as it has highest percentage of CH3.
24:
CH3CHO→CH3CH(OH)CN->CH3CH(OH)CO2H→CH3CH(OH)CO2CH3(esterification)

 

[Suchal Riaz]

Bro dont waste your time on already answered questions

how do i know that the quesstion i am typing is being typed by another person too.

 

[GCE As and a level]

Where can i find june and nov 2001 question papers

i think they r nt available

 

[..sacrifice4Revenge..]

how do i know that the quesstion i am typing is being typed by another person too.

You dont say! :O

Anyways
Plz
https://www.xtremepapers.com/community/attachments/45117/
Ans is c, how?

 

[Rockstar RK]

calculate energy needed to break the bonds - energy released when bonds formed . the most negative asnwer on the right side and most positive to the left side. example:
in P: Br-Br is brocken and no bond is made so 193-0=+193
in Q: no bonds are broken only bond make is Cl-Cl so 0-244=- 244
in R CH3 + cl → CH3Cl only bond made is C-Cl. so -340
in S only bond broken is C-H = +410
negtive →→→ postive
-340(R) → -244(Q) → +193 → 410(S)

Thank u brother

 

[Suchal Riaz]

Suchal Riaz

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w11_qp_12.pdf

9(D),36(D),39(C)

in 36 spontenously means 'by itself' it means that unlike SO2→SO3 which needs a catalyst it happens naturally. so it must be NO→NO2
Nitrogen has two of it's electron bonded. rest of the three are like 2 paired and one unpaired.

39:
in (2) the ester will hydrolyse to form ethanoic acid and methanol. in (3) the nitrile will hydrolyse with alkali to make CH3CO2 and with H+ it will make ethanoic acid too. in (1) substituition or elimination will take place with aqueous OH

 

[roxylara]

Someone please explain these 3 to me

 

[sweet.sugar]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s12_qp_12.pdf
Q6-c ( i got D 21.6 i did the calculation twice got 0.06 mol 7dm^3 and temp 303 n calcultaed it using them )
Q20-c (plz write the calculation)
Q24-A ( octene ha c8h18 so wen it cracks the products will add up to be with in the molecular formula of octene ryt)
Thanks.

 

[Suchal Riaz]

You dont say! :O

Anyways
Plz
https://www.xtremepapers.com/community/attachments/45117/
Ans is c, how?

all C=C can show cis-trans
it's more like permutation of mathematics.
first C=C can be cis and trans, second can be either, third can be either
there are two arrangements for first, two for second and two for third: 2*2*2=8

 

[Suchal Riaz]

i think they r nt available

please remove your signature it makes it more difficult to scroll as it makes the page bigger. and it's agains the rules: Terms and Rules

 

[MYLORD]

C

can u help me solve this
ans is c

 

[_Ahmad]

Bro dont waste your time on already answered questions

Don't say like this. You should have checked the question if it is repeating or not before asking.
now he spend his time to solve your doubt so you should appreciate him instead of saying like this

 

[_Ahmad]

in 36 spontenously means 'by itself' it means that unlike SO2→SO3 which needs a catalyst it happens naturally. so it must be NO→NO2
Nitrogen has two of it's electron bonded. rest of the three are like 2 paired and one unpaired.

39:
in (2) the ester will hydrolyse to form ethanoic acid and methanol. in (3) the nitrile will hydrolyse with alkali to make CH3CO2 and with H+ it will make ethanoic acid too. in (1) substituition or elimination will take place with aqueous OH

Thanks alot

 

[Zepudee]

the same questions are asked again and again.
27:
the alcohol is tertiary and have a chiral carbon with least number of carbons: so chiral carbon has one CH3 one OH one C2H5 and one C3H7 attached to it. this is the only way to make the n smallest and still have a teriary alcohol with chiral carbon
8:density depends on Mr. the average Mr of D looks high as it has highest percentage of CH3.
24:
CH3CHO→CH3CH(OH)CN->CH3CH(OH)CO2H→CH3CH(OH)CO2CH3(esterification)

Thank you so much suchal riaz! and sorry for bothering you.

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w11_qp_12.pdf
Q26 (A), Q30 (A)

THANK YOU SO SO MUCHHHHHH!! please help

 

[Suchal Riaz]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_12.pdf
Q6-c ( i got D 21.6 i did the calculation twice got 0.06 mol 7dm^3 and temp 303 n calcultaed it using them )
Q20-c (plz write the calculation)
Q24-A ( octene ha c8h18 so wen it cracks the products will add up to be with in the molecular formula of octene ryt)
Thanks.

number of moles = 0.96/32=0.03 moles
P=nRT/V=.03moles*8.31*(273+30)K / 7000x10^-6 m²=10.7KPa

 

[..sacrifice4Revenge..]

Don't say like this. You should have checked the question if it is repeating or not before asking.
now he spend his time to solve your doubt so you should appreciate him instead of saying like this

K ahmad,K, my doubt? K.

 

[GCE As and a level]

please remove your signature it makes it more difficult to scroll as it makes the page bigger. and it's agains the rules: Terms and Rules

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

 

[ashcull14]

+1 to this,
Ans is C

sorry, didnt get u...how is it c cn u plx explain

 

[ashcull14]

Its the old rule of electrochem, the one in O levels.
Remember the order, K,Na,Ca,Mg,Al,Zn,Fe,Pb,i dnt remember,Cu,
So Cu is more electro positive than Al and will be reduced at cathode, and vice versa

thnks