Chemistry: Post your doubts here!

[Haya Ahmed]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_qp_23.pdf

Q2e how to calculate the number of electrons ?!

 

[BeBeskii108]

Does anyone have A2 frequently asked question material ?

 

[AbbbbY]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_23.pdf

Q2e how to calculate the number of electrons ?!

Seriously?
Carbon has 6 electrons. Hydrogen has 1. So total = 18.

 

[danial 234]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_21.pdf


Q5 b(ii) and (iii) explain why we multiplied by 2 in (i) arent we supposed to divide by 2 ?

we will multiply by two cz the ques asks to write the number of atoms of hydrogen produced , and in one molecule of hydrogen, there are two atoms of H .. so we will multiply by 2 ... and then calculate the moles of X.. number of moles of X = 0.0067 moles.... H atoms= 0.0133 ..
if there is one OH then one H will be produced
and in X.. for 1 mole of X.. two moles of H ztoms are produced
so there are two OH in each molecule of X

 

[omaaaar]

How to calculate enthalpies using bond energies
And also can someone explain me the Hess ' s cycle

 

[Princess Raven]

can someone show how to draw the skeletal formula of both cis trans isomers of but-2-ene

 

[sitooon]

How to draw this :
PS : As students take care , this might be the question for you this session !!!

 

[AbbbbY]

can someone show how to draw the skeletal formula of both cis trans isomers of but-2-ene

 

[AbbbbY]

How to draw this :
PS : As students take care , this might be the question for you this session !!!
View attachment 41393

I'd go witth something like this

Though, I'm not sure exactly what the full question is. I guess it's asking for NO3- ion

 

[hope4thebest]

Ethanol yes Ethanoic Acid no.

Ethanol has an alcohol group besides a CH3- link so it'll show you a positive test with alkaline iodine.
See ethanol and think 3D. If it still doesn't make sense quote me and tell me I'll draw it out.

Doesn't CH3-CO group give positive test in iodoform test. Ethanoic acid involves CH3-CO group.

 

[AbbbbY]

Doesn't CH3-CO group give positive test in iodoform test. Ethanoic acid involves CH3-CO group.

You're very right that ethanoic acid has a terminal methyl with CO, but the C=O is delocalized here over the entire group. Remember how 2,4 DNPH reacts with carbonyl groups but not carboxylic groups even though all three have at least one C=O? Precisely that principle is applied here.

 

[hope4thebest]

You're very right that ethanoic acid has a terminal methyl with CO, but the C=O is delocalized here over the entire group. Remember how 2,4 DNPH reacts with carbonyl groups but not carboxylic groups even though all three have at least one C=O? Precisely that principle is applied here.

does I2 and NaOH also behaves as oxidising agent?

 

[papajohn]

Best of luck for all those appearing for Chemistry P2..

 

[robinhoodmustafa]

does I2 and NaOH also behaves as oxidising agent?

Iodine is a strong reducing agent because of that extra electron which is less attracted to the nucleus
and Na0H is a weak oxidizing agent since only H atom is reduce.

Correct me if I am wrong!

 

[biscuitbiscuit]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w10_qp_23.pdf
Q3(c)(i) and (ii)

 

[Newbie]

Entirely BOGUS SITES NOT A HELP TO ANY ONE!!!!

Except for the first link,all of them are working.

You need to press skip ad button on top right corner of the page.

 

[sitooon]

I'd go witth something like this

Though, I'm not sure exactly what the full question is. I guess it's asking for NO3- ion

your answer is right , but how did you figure out that one will be double and the other two will be single bond?

 

[yousef]

How to find the structure similar to F
and draw structural isomer in latest paper?

 

[Jelleh Belleh]

How to draw this :
PS : As students take care , this might be the question for you this session !!!
View attachment 41393

What makes you think it'll come?

 

[kitkat <3 :P]

Q1 part b) please :/http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s03_qp_2.pdf