Chemistry: Post your doubts here!

[smartangel]

yes.. the answer is C but due to lack of skills i cant draw all the structures here..but can guide you just by sayin k if you use 1 cl, you can only have 1 orientation .. by using 2,3orb 4 carbons you can only make 2 2 and 2 orientations of the structure of chloroethane...

can you draw them on paint and then post it as a file? its ok. i"ll excuse the bad drawing if thats the problem

 

[hmlahori]

Have some doubts people give a response im posting this for the second time!

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w11_qp_11.pdf
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w11_ms_11.pdf
Q16 I'm confused between options B & C. Clarify why its B.
Q36 The non-metallic element has to be nitrogen. It satisfies all the conditions in the question and the statements 1 & 2. But how is nitrogen dioxide polar?

 

[umarashraf]

can you draw them on paint and then post it as a file? its ok. i"ll excuse the bad drawing if thats the problem

mate i have my Maths P1 tomorrow...(Cambridge) so i hope you understand... drawing take a massive time for me on paint

 

[Oliveme]

Please help me with these questions 8, 11, and 17. http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_w02_qp_1.pdf

And also, questions 16, and 26. http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_s03_qp_1.pdf

 

[hihi]

thanks but can you explain why is this the answer?

u r wecome, it is correctly balanced equation and they ask u 4 which you put in front of (as far as i remember the question) I2 and H2O, u understand now?

 

[smartangel]

Have some doubts people give a response im posting this for the second time!

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w11_qp_11.pdf
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w11_ms_11.pdf
Q16 I'm confused between options B & C. Clarify why its B.
Q36 The non-metallic element has to be nitrogen. It satisfies all the conditions in the question and the statements 1 & 2. But how is nitrogen dioxide polar?

in 16 read the question again. it says the cell is kept cold. with cold Naoh NaClO is formed not NaClO3. you"ve to learn these rxns.
in 36, nitrogen dioxide is very much polar. positive nitrogen atom and 2 negative oxygen hence overall is it polar!

 

[smartangel]

mate i have my Maths P1 tomorrow...(Cambridge) so i hope you understand... drawing take a massive time for me on paint

oh its okay. thanks for the help though

 

[umarashraf]

oh its okay. thanks for the help though

you welcome mate.... will answer u tomorrow...!!!

 

[sumaiyarox:)]

Split the ester by drawing a straight line through the middle of O2 and you will get these 2 compounds:

C2H5C & CH3

The carbon without the hydrogen (first one) will be the acid and the other one will be the alcohol. So your alcohol is CH3OH and the acid is C2H5CO2H. Since you boiled with aq. NaOH, the carboxylic acid becomes C2H5CO2Na.

mate first of all .. alcohols donot react with sodium hydroxide... secondly propanoic acid is an acid while sodium hydroxide is a base... this will readily react and form salt + h2O.... (acid base titration)

they react to give salt and ALCOHOL in case of esters...so over here u get a sodium salt (i.e ethyl ethanoate )and an alcohol(ethanol)

 

[smartangel]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w05_qp_1.pdf
Q3..please explain it to me!
also q12..shouldnt the answer be D?

 

[smartangel]

20 What is the number of isomers of C2H2Cl2 including cis-trans isomers?
A 2 B 3 C 4 D 5
and B. besides cis trans whats the other isomer that we get?

 

[Casablanca]

20 What is the number of isomers of C2H2Cl2 including cis-trans isomers?
A 2 B 3 C 4 D 5
and B. besides cis trans whats the other isomer that we get?

I THINK the answer is 2.

Because number of isomers = 2^n and n is the number of double bonds. In the case of C2H2Cl2 we only have one double bond, so 2^1 is 2.

But I think you should wait for someone to confirm it, because I'm not that good at chemistry.

 

[smartangel]

I THINK the answer is 2.

Because number of isomers = 2^n and n is the number of double bonds. In the case of C2H2Cl2 we only have one double bond, so 2^1 is 2.

But I think you should wait for someone to confirm it, because I'm not that good at chemistry.

i chked the marking scheme it says C.

 

[smartangel]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w05_qp_1.pdf
Q3..please explain it to me!
also q12..shouldnt the answer be D?

 

[smartangel]

http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_w06_qp_1.pdf
in 5 why cant the answer be D? i dont get what the examiner report is trying to say. please explain!!!

 

[egy]

hi i just wanted to ask is any of u guys is from Egypt and appearing as a private candidate please reply

pleassssssssseeeeeeeeeeeeeeeeeee

 

[egy]

private student in Egypt

 

[smartangel]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w04_qp_1.pdf
Q34..plz explain second n third statements.
Q23 as well!

 

[egy]

no one is from egypt

 

[umarashraf]

they react to give salt and ALCOHOL in case of esters...so over here u get a sodium salt (i.e ethyl ethanoate )and an alcohol(ethanol)

what point you are actually trying to raise here...??? esters are hydrolysed first.. then the reaction is followed by mere titration... this is what i believe...