Chemistry Paper 2

[Pals_1010]

Quote me the values and I'll solve it here!

Delta change of combustion:

CO --------------> -283

H2 --------------> -286

Methanol--------> -726

 

[dayeed]

I am expecting 33 in p12, 47 in p22 and 21 in p33. What grade should I expect?

it depends if u manage to get about 55 u can get an A warna B for sure ,,,,,, dua kro k u get some extra marks then u will get an A for sure =)

 

[Soulgamer]

Delta change of combustion:

CO --------------> -283

H2 --------------> -286

Methanol--------> -726

=((-283)+(2 x -286)) - (-726)
=(-283-572) + 726
=-855+726
=-129 KJ/mol

 

[Pals_1010]

=((-283)+(2 x -286)) - (-726)
=(-283-572) + 726
=-855+726
=-129 KJ/mol

Thanks ... I didn't know we could use this method

So when you use this formula, it is combustion of REACTANTS minus combustion of PRODUCTS in this one?
(compared to formation of products minus formation of reactants)

 

[Silent Hunter]

=((-283)+(2 x -286)) - (-726)
=(-283-572) + 726
=-855+726
= -129 KJ/mol

So its correct... Alhamdulilah got that one right..... was having serious confusion over this 3 mark

 

[Silent Hunter]

Notice the green negative sign ... which caused all confusion

 

[Pals_1010]

Notice the green negative sign ... which caused all confusion

Arguing and fighting like wolves over one mark only. Oh CIE What have you made us into ?

 

[Silent Hunter]

Arguing and fighting like wolves over one mark only. Oh CIE What have you made us into ?

well well those who got that wrong... might have used wrong formula in the first step... so wont they get 3 marks cut.... cuz if you do like products - reactants its + but reactants - products is - so....?

 

[Pals_1010]

well well those who got that wrong... might have used wrong formula in the first step... so wont they get 3 marks cut.... cuz if you do like products - reactants its + but reactants - products is - so....?

Maybe 1 mark for the value of 129 but mark deducted for the sign and formula.

 

[Silent Hunter]

lets hope for the best you got that one correct nah?

 

[Silent Hunter]

i made aldehyde for the last page question asking for diagram of functional group silly me so the next question was automatically wrong.... wont it be or ecf will help me here?

 

[Pals_1010]

lets hope for the best you got that one correct nah?

Yeah. Just hope the rest went just as fine

Your paper went okay?

 

[Pals_1010]

i made aldehyde for the last page question asking for diagram of functional group silly me so the next question was automatically wrong.... wont it be or ecf will help me here?

May the force of ECF be with you

 

[Silent Hunter]

rest was fine as far as i remember Alhamdulilah
but that cis trans one.... how did ya draw it? confused over it still

 

[Pals_1010]

rest was fine as far as i remember Alhamdulilah
but that cis trans one.... how did ya draw it? confused over it still

Something like that.... Not entirely sure though

 

[Silent Hunter]

so u drew the same as this pic? i drew the same exact

 

[Assad Ali]

what about the question 1?which required to write a liquid from the period 3?

 

[Pals_1010]

so u drew the same as this pic? i drew the same exact

*high five* Let's hope it's correct then

 

[Silent Hunter]

hopefully

 

[Assad Ali]

Something like that.... Not entirely sure though

this one is wrong....it had only two carboxlic groups.