June 2014 ocr chemistry f322

how do u know its water for question 5bi (see vid below):
https://www.youtube.com/watch?v=jGX4129O5OA&list=PLi6oabjl6coxZJmEYIXKxFisBzAhjyIYr&index=5
for question 7a the mark scheme accepts i2 and cl2 as well but why couldn't u have other group 7 molecules e.g. f2
https://www.youtube.com/watch?v=m1JJa572leQ&list=PLi6oabjl6coxZJmEYIXKxFisBzAhjyIYr&index=7
for question 8b, why do they only give some structures one mark- see mark scheme which I will attach and link below for question:
https://www.youtube.com/watch?v=EII_cyK090A&list=PLi6oabjl6coxZJmEYIXKxFisBzAhjyIYr&index=8

Reply 1

runny4

OP

6

Original post by runny4

how do u know its water for question 5bi (see vid below):
https://www.youtube.com/watch?v=jGX4129O5OA&list=PLi6oabjl6coxZJmEYIXKxFisBzAhjyIYr&index=5
for question 7a the mark scheme accepts i2 and cl2 as well but why couldn't u have other group 7 molecules e.g. f2
https://www.youtube.com/watch?v=m1JJa572leQ&list=PLi6oabjl6coxZJmEYIXKxFisBzAhjyIYr&index=7
for question 8b, why do they only give some structures one mark- see mark scheme which I will attach and link below for question:
https://www.youtube.com/watch?v=EII_cyK090A&list=PLi6oabjl6coxZJmEYIXKxFisBzAhjyIYr&index=8

mark scheme

F322_MS_Jun14.pdf582.9KB

Reply 2

thymolphthalein

4

Original post by runny4

how do u know its water for question 5bi (see vid below):
https://www.youtube.com/watch?v=jGX4129O5OA&list=PLi6oabjl6coxZJmEYIXKxFisBzAhjyIYr&index=5
for question 7a the mark scheme accepts i2 and cl2 as well but why couldn't u have other group 7 molecules e.g. f2
https://www.youtube.com/watch?v=m1JJa572leQ&list=PLi6oabjl6coxZJmEYIXKxFisBzAhjyIYr&index=7
for question 8b, why do they only give some structures one mark- see mark scheme which I will attach and link below for question:
https://www.youtube.com/watch?v=EII_cyK090A&list=PLi6oabjl6coxZJmEYIXKxFisBzAhjyIYr&index=8

b)i) Combustion reaction for a hydrocarbon (like ethane) for example, in excess oxygen would produce carbon dioxide and water.

Combustion reaction of a hydrocarbon in limited oxygen could produce carbon dioxide/carbon monoxide and water.

A halogenated hydrocarbon could produce a mixture of carbon dioxide/carbon monoxide/hydrogen chloride and water.

See the pattern here? So if they tell you that a combustion reaction forms carbon dioxide, carbon monoxide, hydrogen chloride and a non-toxic product. It should be water.

7)a) Fluorine is the most reactive, and you probably won't get the addition reaction with the alkene that you would get with other halogens down the group.

http://www.chemguide.co.uk/organicprops/alkenes/halogenation.html

"Ethene reacts explosively with fluorine to give carbon and hydrogen fluoride gas. This isn't a useful reaction, and you aren't likely to need it for exam purposes in the UK at this level (A level or equivalent)."

8) I can't open that mark scheme for some reason so I can't really comment on it.

Edit: Found another mark scheme. I don't understand your question?
There's 6 marks in total.
One mark is for finding the molar mass of B.
One mark each for structure of B, C, D, E and F.

(edited 8 years ago)

Reply 3

runny4

OP

6

Original post by thymolphthalein

b)i) Combustion reaction for a hydrocarbon (like ethane) for example, in excess oxygen would produce carbon dioxide and water.

Combustion reaction of a hydrocarbon in limited oxygen could produce carbon dioxide/carbon monoxide and water.

A halogenated hydrocarbon could produce a mixture of carbon dioxide/carbon monoxide/hydrogen chloride and water.

See the pattern here? So if they tell you that a combustion reaction forms carbon dioxide, carbon monoxide, hydrogen chloride and a non-toxic product. It should be water.

7)a) Fluorine is the most reactive, and you probably won't get the addition reaction with the alkene that you would get with other halogens down the group.

http://www.chemguide.co.uk/organicprops/alkenes/halogenation.html

"Ethene reacts explosively with fluorine to give carbon and hydrogen fluoride gas. This isn't a useful reaction, and you aren't likely to need it for exam purposes in the UK at this level (A level or equivalent)."

8) I can't open that mark scheme for some reason so I can't really comment on it.

Edit: Found another mark scheme. I don't understand your question?
There's 6 marks in total.
One mark is for finding the molar mass of B.
One mark each for structure of B, C, D, E and F.

ur looking at 8a not 8b

Reply 4

Pigster

20

They only give some structure one mark because they are wrong, but not so wrong as to get no marks.

The first line of question (b) is often forgotten... "Compound G is a branched-chain organic compound that does not have E and Z isomers".

Look again at the 'wrong' but mark-worthy answers and you'll see that they are not possible, but still fit with the elemental analysis, MS and IR data.

Reply 5

thymolphthalein

4

Original post by runny4

ur looking at 8a not 8b

Oooh, sorry. I'm a very sleep deprived individual, it happens. :biggrin:

2 marks for the structure of G.
I'm guessing it's one mark for the correct position of the carbon-carbon double bond(based on information from the given mass spectrum + not having E/Z isomers) and one mark for the rest of the structure being correct.

Reply 6

runny4

OP

6

Original post by thymolphthalein

Oooh, sorry. I'm a very sleep deprived individual, it happens. :biggrin:

2 marks for the structure of G.
I'm guessing it's one mark for the correct position of the carbon-carbon double bond(based on information from the given mass spectrum + not having E/Z isomers) and one mark for the rest of the structure being correct.

yeah but they've given only one mark for cyclic carboxylic acids and on the examiners report it says somethig about the number of hydrogens suggesting a double bond