OCR AS - Chemistry Unit F322 - Chains, energy and resource - REVISION!

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Surely the answer to the whole methanol thing is the paragraph from the OCR textbook?

"clean burning fuel...high performance cars...extremely toxic and ingestion can lead to severe organ damage and death...people died. Methanol is an important chemical feedstock and can be converted into methanal and methanoic acid?"

Reply 981

shooby_doo

Original post by Thompson93

In the nucleophilic substitution i showed K. So I showed the OH breaking off from the K etc. Will I still get the marks? It meant that I ended up with KBr :s-smilie:

Thats what i was unsure about aswell :s-smilie:

So i decided to leave it as (K+) + Br-
Instead of Kbr

Reply 982

Music22

Were the only equations that we had to write out, was it just the radical one and the incomplete/complete combusion? I keep on thinking that there was another one to do with NO, and it's really bugging me?

Reply 983

shooby_doo

Answer:
You can drink ethanol.
If you drink methanol, even a small amount, you will go blind.

Read more: http://wiki.answers.com/Q/Which_can_you_drink_ethanol_or_methanol#ixzz1NZpfS1W4

Reply 984

Phenylethylamine_

Original post by shooby_doo

Wait !
I thought that an increase in bond enthalpy means that it means the bond is stronger :confused:

I got the concept of it that bond enthalpy's are more of an important factor ... But i said that bond enthalpies increase down the group ... :/

Yep, so there's a decrease in bond enthalpy down the group i.e. the bond strength becomes weaker, so the as you go down the bonds can break more easily :wink:

Reply 985

Phenylethylamine_

Original post by Thompson93

In the nucleophilic substitution i showed K. So I showed the OH breaking off from the K etc. Will I still get the marks? It meant that I ended up with KBr :s-smilie:

Yep, it is KBR in the overall equation of the reaction :wink:

Reply 986

bites

Original post by amyyy24

I put methylated spirits, as that was the ist thing that came into my mind-

its says in the textbook, just above the para that u just quoted. bt im not so sure?
help!

Reply 987

Thompson93

Original post by Phenylethylamine_

Yep, it is KBR in the overall equation of the reaction :wink:

Thanks, some of my friends said that it was wrong to show K, and that you should only show OH in the mechanism.

Reply 988

shooby_doo

I got ethylethanoate for Z ....
...
..
.

Reply 989

medusa cascade

Original post by bites

I put methylated spirits, as that was the ist thing that came into my mind-

its says in the textbook, just above the para that u just quoted. bt im not so sure?
help!

Well methanol is used in methylated spirits but it does say that in the question and then ask for OTHER things, I think?

Reply 990

NRT

Original post by Thompson93

Thanks, some of my friends said that it was wrong to show K, and that you should only show OH in the mechanism.

If you showed OH minus as the attacking nucleophile then showing BR minus at the end is fine, i think what you did is also correct. You had to show an equation too so yeah KBr was one of the products in that including propanol.

Reply 991

medusa cascade

Original post by shooby_doo

I got ethylethanoate for Z ....
...
..
.

It was ethyl propanoate, because the carboxylic acid was propanoic acid, iirc. CH3CH2COOH.

Reply 992

786girl

please could someone clarify these;

1. general formula of alcohol, why cant it be CnH2n+2O

2. international cooperation?

3. for the hydrolysis question - how many marks was it?

4. the last question i got the alcohol wrong but i got up to identifying its fragment and molecular formular but i drew it wrong which lead me to name it wrong which lead me to identify X as propyl propanoate! how many marks do u reckon i lost?

Reply 993

shooby_doo

Original post by medusa cascade

It was ethyl propanoate, because the carboxylic acid was propanoic acid, iirc. CH3CH2COOH.

OMG i drew it out as propanoic acid But i named it wrong to ethanoic acid!
Which is why i called it ethylethanoate ....
NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO

Reply 994

vfest

Original post by broken_glass_heart

yeh sooooo badly,

ahhh nvr mind im sure you did fine anyway cause u probably got the other questions right :smile:

i didnt really know any of the questions :s-smilie:

Reply 995

786girl

Original post by shooby_doo

Wait !
I thought that an increase in bond enthalpy means that it means the bond is stronger :confused:

I got the concept of it that bond enthalpy's are more of an important factor ... But i said that bond enthalpies increase down the group ... :/

bond enthalpy decreases down the group so Br WOULD react faster

Reply 996

shooby_doo

Original post by 786girl

bond enthalpy decreases down the group so Br WOULD react faster

Yeah i was meant to write it the other way round werent i ....

Even though i still concluded that Br will be more reactive than cl ...
So is that a mark lost? :mad:

Reply 997

786girl

Original post by amyyy24

hey btw i got an offer from qmul for biomed too but my offer is AAB ¬_¬ ??

Reply 998

786girl

Original post by shooby_doo

Yeah i was meant to write it the other way round werent i ....

Even though i still concluded that Br will be more reactive than cl ...
So is that a mark lost? :mad:

Just one

dont worry ive lost a dozen...

Reply 999

username791037

When working out the empirical formula on the last question i got oxygen to be 1.5, but surely that can't be the empirical formula because it isn't a whole number but i thought it would be unreliable to round it up to 2, did anyone else get this? i left it as 1.5 and at the end got Ethyl propanoate