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

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Reply 1180
Avatar for king1234
king1234
Original post by nereik6794
There were 2 but I can't remember what I put either haha. I think it was correct though


i can r ember there where to alkenes next to each other and one was an ez other wasn't because it didn't have two groups attached to c double bound c never mind i prob got it wrong
Reply 1181
Avatar for l.a.s
l.a.s
Original post by thefirstnotlastsamurai
Yeah there was one actually.

2NO + O2 ------> 2NO2 or something like that?


i put: (wasn't entirely sure)

NO + 02 -> NO2. + O (in that it formed another radical? like in the mechanism?)
Reply 1182
Avatar for king1234
king1234
Original post by kimmey
for the one where u had to draw 2-methyl-propan-2-ol would u get the marks if u drew a DISPLAYED formula ? cus on most mark schemes they seem to have skeletal ????? :smile:


you would get the marks because i drew displayed formula
^H= 66 question?

what number did ppl put for it, (lol i just put 66)
Original post by potentialmedicalstudent
^H= 66 question?

what number did ppl put for it, (lol i just put 66)


33 but I have no idea if that's correct lol
Reply 1185
Avatar for king1234
king1234
Original post by potentialmedicalstudent
^H= 66 question?

what number did ppl put for it, (lol i just put 66)


so did i but people on here say half the number
Original post by king1234
you would get the marks because i drew displayed formula


What I did was for the H2 draw the H's coming off. For the HBr I drew the H at one place and Br at the other and then swapped them for the 3rd drawing. Does this get the marks? With the double bond broken of course
Reply 1187
Avatar for l.a.s
l.a.s
Original post by Tasha001
yeah it was 46. i spent ages trying to find how it would be 47 :confused:


47 was there because of the isotope carbon-13 in some of the molecules, so there's a small peak to the right of the molecular ion due to that isotope in some of the molecules.
Reply 1188
Avatar for king1234
king1234
Original post by nereik6794
What I did was for the H2 draw the H's coming off. For the HBr I drew the H at one place and Br at the other and then swapped them for the 3rd drawing. Does this get the marks? With the double bond broken of course


erm 50/50 you might depends on the examiner tbh
Reply 1189
Avatar for l.a.s
l.a.s
Original post by nereik6794
33 but I have no idea if that's correct lol


it was 33, i think the reason that they asked the question is to make sure people understood that the enthalpy change in formation is the enthalphy change when ONE mole of a compound is made, there was 2 Moles of it whe it was 66, so it must've been 33 for one mole!
Original post by l.a.s
it was 33, i think the reason that they asked the question is to make sure people understood that the enthalpy change in formation is the enthalphy change when ONE mole of a compound is made, there was 2 Moles of it whe it was 66, so it must've been 33 for one mole!


Yeh I doubled it at first then I was thinking "lol wtf". So then I crossed my answer and wrote 33
Reply 1191
Avatar for king1234
king1234
is anyone going to post an unoficcial markshcheme
Original post by king1234
erm 50/50 you might depends on the examiner tbh


Let's hope he/she isn't a complete ***** then
Reply 1193
Avatar for bagelbe
bagelbe
for the hydrolysis one, does polarity decrease down the group?
and for the why is it exothermic one, is it because it requires more energy to break the bond than forming them resulting in a negative delta H value?
Original post by bagelbe
for the hydrolysis one, does polarity decrease down the group?
and for the why is it exothermic one, is it because it requires more energy to break the bond than forming them resulting in a negative delta H value?


Weaker bond enthalpy down the group. Less energy to break the bonds than the energy released forming the new bonds.
Reply 1195
Avatar for bagelbe
bagelbe
Original post by nereik6794
Weaker bond enthalpy down the group. Less energy to break the bonds than the energy released forming the new bonds.


Do you think I'll get a mark for writing that hydrolysis with Cl occurs faster as polarity decreases down the group?
Reply 1196
Avatar for king1234
king1234
Original post by nereik6794
Let's hope he/she isn't a complete ***** then


what did you get for ez isomer im sure there was only one ez isomer
Original post by bagelbe
Do you think I'll get a mark for writing that hydrolysis with Cl occurs faster as polarity decreases down the group?


I think so
Original post by king1234
what did you get for ez isomer im sure there was only one ez isomer


Yes exactly! I chose the one on the bottom left, I can't remember what the letter was though. It consisted of a C=C bond, one Hydrogen attached to each Carbon and then I think it was a CH3 group attached to each Carbon
Reply 1199
Avatar for bagelbe
bagelbe
Original post by nereik6794
I think so


Awesome :biggrin:

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