This discussion is now closed.

Check out other Related discussions

EDEXCEL CHEMISTRY 6B - 19th June - 12hrs passed!

dreamer*girl

what was your answer for the part in q3 which said something like: why is heat given out when anhydrous aluminium chloride is added to water?
i said new bonds are created. bond-making is exothermic, and the energy is given out as heat energy.
i think its probably wrong, but oh well..

Mine was something along those lines. Ionic bonding in CuSO4 and hydration enthalpies are always exothermic due to bonds being formed.

Reply 61

petzneo

15

dreamer*girl

what was your answer for the part in q3 which said something like: why is heat given out when anhydrous aluminium chloride is added to water?
i said new bonds are created. bond-making is exothermic, and the energy is given out as heat energy.
i think its probably wrong, but oh well..

I said that too!

Reply 62

jsp13

guys i dont get it was it necessary for us to MAKE the grignard reagent?

couz my answer was that ethene would undergo complete combustion to form CO2 and H2O
then by adding the suitable grignard reagent we can make propanoic acid
i gues ill at least get 3 marks for addition if the correct G.R to CO2 and showing the reaction correctly

Reply 63

Flower404

no mark scheme up yet?

Reply 64

Mehrino

jsp13

guys i dont get it was it necessary for us to MAKE the grignard reagent?

couz my answer was that ethene would undergo complete combustion to form CO2 and H2O
then by adding the suitable grignard reagent we can make propanoic acid
i gues ill at least get 3 marks for addition if the correct G.R to CO2 and showing the reaction correctly

Well the question said something like 'via a Grignard reagent' so yes, you did have to make it. Although your method is correct in that you reacted a Grignard with CO2, you'd have to specify that it was solid CO2, in cold conditions and the addition of HCL to liberate the acid.
Hope that helps.

Reply 65

mkchelsea

1

fn137

Im not sure if this is correct but what do u guys think ....
I reacted ethene with CH3MgBr and then acidified to get propanol , reacted that with acidied K2Cr2O7 to get propanoic acid...

all the other answers discussed here ,all those calculations yes even I got those!

What was the overall ionic equation in the 4th question??? I really got stuck in that one...though its supposed to be the easiest... :frown:

lol thats what i done as well, ah well lol

Reply 66

lozzaisdabestever

wow, this was my last exam and it made me so unbelievably happy, question 3 was absolutely incredible, no organic whatsoever, which was amazing! Question 1 was sort of OK, question 4 not too bad although got stuck on the part about lack of optical activity in the product. Overall not bad at all, far better than the mock and past papers I did.

Reply 67

aminalia89

13

Mehrino

Well the question said something like 'via a Grignard reagent' so yes, you did have to make it. Although your method is correct in that you reacted a Grignard with CO2, you'd have to specify that it was solid CO2, in cold conditions and the addition of HCL to liberate the acid.
Hope that helps.

the question asked for reagents not conditions but it wouldn't hurt to put solid co2 at a low temperature.

Reply 68

Dr Acula

3

tami*

i get up to there and decide to multipy by the Mr of propanoic acid :mad:

i messed up hat paper so bad

and to add t my stupidness for the reaction scheme for the grignard...i did the mechanism

think i've lost about 25 marks there :mad:

change your sig you are no longer a potential gap yearer or medicine candidate! :biggrin:

go biomed!!!

Reply 69

clearvisionafterdeath

you know the grignard reagent question , i reacted ethene with hydrogen bromide, then react bromoethane the product with magnesium to form the grignard reagent ethyl magnesium bromide , then finally react the ethyl magnesium bromide with carbon dioxide to form propanoic acid. who did the last question on question 3, i put down that sodium chloride is an ionic solid , dissolves in water to form na+ and cl- which are equal in charge, thus neutral solution formed, and for the sodium propanoate i wrote down that sodium propanoate reacts with water to form propanoic acid and sodium hydroxide <<<that makes soluion alkaline. sorry about the long post

Reply 70

Westupper

Have edexcel put up an unofficial markscheme yet?

Reply 71

mcgangstaz

did people understand the first question..i didnt understand the use of 30g

Reply 72

fn137

11

someone pls give the link to the prestandardised marking scheme for this paper...

Reply 73

Westupper

Lol I wish someone had that link!!

Reply 74

mcgangstaz

i reacted ethene with hbr to give c2h5br then i added mg with dry ether ,then solid carbon dioxide and hydrochloric acid to make propanoic acid,but i forgot to include the formula of the grignard reagent,so i basically had 2 steps,,hw many markz do u think i will get 4 this