Qualification > Sciences

chemistry paper 31 discussions

(1/4) > >>

Alayna:
Hey guys..
how did you find the chemistry paper 31?
i found it pretty nice!
what was the answer to why one reaction takes heating and one occours almost spontaniously?
and how about why the cloride compound could not form but iodine compound could?
and why is bromine a licquid and clorine a gas at room temprature?

Aly:
yeah it was good :)
better than the past pprs atleast :)
i had problems wid the same qns..
i xplained electronegativity for the chloride n iodide qn...donno how far its ryt!
n for y chlorine is a gas n bromine a liquid...i xplained van der waals forces of atraction!

wat dd u rytt?
n u think the thresholds gonna b high?

oh yeah..the oxide was OF2 yeah?

sammwangi:
hey!
The paper was ok. I also got F20 for the oxide of the most electronegative element and i also explained the existence of the iodine compund and the non existence of the chlorine compund in terms of the small difference in electronegativity for the Cl and F bt the larger electronegativity difference for the  i anf f hence the compund exhibits enhanced stability.

What did you say fopr the two reactions with NaOH, one was the nucleophilic substitition of a halogenoalkane while the other was the neutralisation reaction of Hcl with NaOH. Why did the hyalegenoalkane need heating while the nuetralisation was almost instantaneous???

 ??? ??? ??? ???
I wrote that the nucleophilic substitutin was endothermic and had a large activation energy hence requires heating inorder to enable the reaction to go on to completion. I then said the neutralisation was exothermic and hence the initial reaction provides enough energy to activate the subsequent reaction as the Ea was small in comparison to the enegy evovled by the reaction... is this ok for the 4 marks... A couple of guys explained it in terms of the existence of the intermediary in the nuclephilic substitution while the nuetralisation was a simple bimolecular reaction. (activated complex theory) 

Help  :-\

rina94:
hey guys!
i just wanted to ask which country you live in :)

i hope you all get great grades ;)

leebux101:
i wrote about intermediate compounds and activation energy for the 2 reactions...and i also identified them.

and for the chlorine and iodine with fluorine..i wrote abt electronegativity too...

for chlorine and bromine..i wrote abt van der waals forces...

Navigation

[0] Message Index

[#] Next page