[NockNock]

For one of the questions it said name the functional groups, I said.
-Cycloalkene
-Alcohol
Is that okay?

[AGrumpyMole]

(Original post by NockNock)
For one of the questions it said name the functional groups, I said.
-Cycloalkene
-Alcohol
Is that okay?

'twas alkene and alcohol wasn't it?

[Salmonidae]

(Original post by NockNock)
For one of the questions it said name the functional groups, I said.
-Cycloalkene
-Alcohol
Is that okay?

(Original post by AGrumpyMole)
'twas alkene and alcohol wasn't it?

I believe it was alkene and alcohol also, so probably 1 mark out of two

[AGrumpyMole]

If the bond angle question was octahedral and 90 and I wrote:

Octahedral
109 degrees (wrong)
4 areas of electron density (2 lone paris and 2 bonding pairs) - wrong also
electrons repel
to get as far away from each other in space

How many marks out of 4 would I get?

[Salmonidae]

(Original post by AGrumpyMole)
If the bond angle question was octahedral and 90 and I wrote:

Octahedral
109 degrees
4 areas of electron density (2 lone paris and 2 bonding pairs) - i know this is wrong
electrons repel
to get as far away from each other in space

How many marks out of 4 would I get?

Well you'd definitely get these two:
electrons repel
to get as far away from each other in space

But as for the other's i'm not sure, because although you correctly stated Octahedral you then contradicted that with the 4 areas of electron density section.
So I'd say 2 is a safe bet

[master_blaster66]

(Original post by :)ella)
Beginnings of an unofficial markscheme:

This is all a mess at the moment because I can hardly remember any of the questions and definitely not the order but I'll try to keep adding to it as people come up with other questions

- properties of gamma radiation:
not deflected by electronic field
highly penetrating
form of EM radiation

what is half-life and why tracers shouldn’t remain in the body for much longer/less than 100 days
- the time it takes for half of a radioactive isotope to decay
- too long and the body will be exposed to radiation for too long which could be harmful OR won’t decay quickly enough to be detected
-too short and the radiation will be too intense which could be harmful OR could decay too quickly to be detected

functional groups: alcohol/hydroxyl and alkene

Formula was C9H10O

Structural isomer – same atoms arranged in a different way
(don’t know how to draw skeletal formulae on a computer sorry!)

Mass spectrometry – 181 was the molecular mass so the calculation was adding up all the RFMs
There was a peak at 181 because that was the mass of the entire molecular ion

other peaks - fragmentation

Benefits of hydrogen - no carbon dioxide produced - CO2 is a greenhouse gas
Disadvantages - must be stored under pressure so it is a liquid

Amount of air question:
60cm3 of fuel = 750cm3 oxygen = 0.75 dm3 oxygen
= 3.57dm3 air

entropy – a measure of the number of ways particles can be arranged

Empirical formula: CH3O (I think you’d still get the marks for COH3)

Shape of SF6 was octahedral, bond angle 90 (NOT 109/107 - it was referring to the SF6 molecule)
6 areas of electron density, sets of electrons repel as far apart as possible

Emission spectra:
-electrons absorb energy, become excited and are promoted to higher energy levels
- emit energy as visible light as they drop back down to original level
- E = hv
- frequencies appear as lines on emission spectrum
- energy levels are quantised and different for every element hence each spectrum is unique

Exothermic question -
-bond breaking is endothermic - energy is taken in
-bond making is exothermic - energy is given out
- if more energy is given out by bond making than was taken in by bond breaking then the enthalpy value will be negative because overall energy is lost

-Mendeveel left gaps for undiscovered elements

Hess cycles
ΔH1 = ΔH2 + ΔH3
Hess’s Law states that the enthalpy change of a reaction is the same no matter what route was taken so the direct route on the diagram has the same enthalpy change as the indirect route

Enthalpy change of formation:

Ga(s) + As(s) --> GaAs(s)
solid because both their melting points are higher than 298K

Relative abundance 69.8

Heterogeneous catalyst - BDAC (I think - I cant remember what the letters were myself but I've seen a few people post that it was this)

Table:
Covalent, simple molecular
(Giant) ionic lattice, high melting point/soluble/ conducts electricity in solution and molten
Covalent

Table: Gallium-71: 31 protons, 31 electrons, 40 neutrons
Gallium-69: 31 protons, 31 electrons, 38 neutrons

is that all questions?

[AGrumpyMole]

(Original post by Salmonidae)
Well you'd definitely get these two:
electrons repel
to get as far away from each other in space

But as for the other's i'm not sure, because although you correctly stated Octahedral you then contradicted that with the 4 areas of electron density section.
So I'd say 2 is a safe bet

Thanks dude

[:)ella]

(Original post by master_blaster66)
is that all questions?

No, it's just the ones I could remember off the top of my head and one's people on this thread have mentioned. The only one I've deliberately missed is the one about clean burning fuels because I had no idea, couldn't see it in the textbooks or revision guides and there are too many definitions on Google!

[the_future]

(Original post by George_)
It wasn't 107 degrees! People saying this should try and give an actual reason!!

they didnt make it clear

[Salmonidae]

(Original post by the_future)
they didnt make it clear

You dont think 'SF₆ is used in toothpaste' or whatever it said was clear enough? As someone pointed out earlier it would be like saying 'H₂O is useful for drinking. Calculate the bond angle of CO₂'

[the_future]

(Original post by :)ella)
Beginnings of an unofficial markscheme:

This is all a mess at the moment because I can hardly remember any of the questions and definitely not the order but I'll try to keep adding to it as people come up with other questions

- properties of gamma radiation:
not deflected by electronic field
highly penetrating
form of EM radiation

what is half-life and why tracers shouldn’t remain in the body for much longer/less than 100 days
- the time it takes for half of a radioactive isotope to decay
- too long and the body will be exposed to radiation for too long which could be harmful OR won’t decay quickly enough to be detected
-too short and the radiation will be too intense which could be harmful OR could decay too quickly to be detected

functional groups: alcohol/hydroxyl and alkene

Formula was C9H10O

Structural isomer – same atoms arranged in a different way
(don’t know how to draw skeletal formulae on a computer sorry!)

Mass spectrometry – 181 was the molecular mass so the calculation was adding up all the RFMs
There was a peak at 181 because that was the mass of the entire molecular ion

other peaks - fragmentation

Benefits of hydrogen - no carbon dioxide produced - CO2 is a greenhouse gas
Disadvantages - must be stored under pressure so it is a liquid

Amount of air question:
60cm3 of fuel = 750cm3 oxygen = 0.75 dm3 oxygen
= 3.57dm3 air

entropy – a measure of the number of ways particles can be arranged

Empirical formula: CH3O (I think you’d still get the marks for COH3)

Shape of SF6 was octahedral, bond angle 90 (NOT 109/107 - it was referring to the SF6 molecule)
6 areas of electron density, sets of electrons repel as far apart as possible

Emission spectra:
-electrons absorb energy, become excited and are promoted to higher energy levels
- emit energy as visible light as they drop back down to original level
- E = hv
- frequencies appear as lines on emission spectrum
- energy levels are quantised and different for every element hence each spectrum is unique

Exothermic question -
-bond breaking is endothermic - energy is taken in
-bond making is exothermic - energy is given out
- if more energy is given out by bond making than was taken in by bond breaking then the enthalpy value will be negative because overall energy is lost

-Mendeveel left gaps for undiscovered elements

Hess cycles
ΔH1 = ΔH2 + ΔH3
Hess’s Law states that the enthalpy change of a reaction is the same no matter what route was taken so the direct route on the diagram has the same enthalpy change as the indirect route

Enthalpy change of formation:

Ga(s) + As(s) --> GaAs(s)
solid because both their melting points are higher than 298K

Relative abundance 69.8

Heterogeneous catalyst - BDAC (I think - I cant remember what the letters were myself but I've seen a few people post that it was this)

Table:
Covalent, simple molecular
(Giant) ionic lattice, high melting point/soluble/ conducts electricity in solution and molten
Covalent

Table: Gallium-71: 31 protons, 31 electrons, 40 neutrons
Gallium-69: 31 protons, 31 electrons, 38 neutrons

Aint the second last question (first part) held by intermolecular bond? its cant be covalent if the question said it had a low melting or a low boiling point whichever it was and so was talking about the individual molecules.

[the_future]

(Original post by :)ella)
Beginnings of an unofficial markscheme:

This is all a mess at the moment because I can hardly remember any of the questions and definitely not the order but I'll try to keep adding to it as people come up with other questions

- properties of gamma radiation:
not deflected by electronic field
highly penetrating
form of EM radiation

what is half-life and why tracers shouldn’t remain in the body for much longer/less than 100 days
- the time it takes for half of a radioactive isotope to decay
- too long and the body will be exposed to radiation for too long which could be harmful OR won’t decay quickly enough to be detected
-too short and the radiation will be too intense which could be harmful OR could decay too quickly to be detected

functional groups: alcohol/hydroxyl and alkene

Formula was C9H10O

Structural isomer – same atoms arranged in a different way
(don’t know how to draw skeletal formulae on a computer sorry!)

Mass spectrometry – 181 was the molecular mass so the calculation was adding up all the RFMs
There was a peak at 181 because that was the mass of the entire molecular ion

other peaks - fragmentation

Benefits of hydrogen - no carbon dioxide produced - CO2 is a greenhouse gas
Disadvantages - must be stored under pressure so it is a liquid

Amount of air question:
60cm3 of fuel = 750cm3 oxygen = 0.75 dm3 oxygen
= 3.57dm3 air

entropy – a measure of the number of ways particles can be arranged

Empirical formula: CH3O (I think you’d still get the marks for COH3)

Shape of SF6 was octahedral, bond angle 90 (NOT 109/107 - it was referring to the SF6 molecule)
6 areas of electron density, sets of electrons repel as far apart as possible

Emission spectra:
-electrons absorb energy, become excited and are promoted to higher energy levels
- emit energy as visible light as they drop back down to original level
- E = hv
- frequencies appear as lines on emission spectrum
- energy levels are quantised and different for every element hence each spectrum is unique

Exothermic question -
-bond breaking is endothermic - energy is taken in
-bond making is exothermic - energy is given out
- if more energy is given out by bond making than was taken in by bond breaking then the enthalpy value will be negative because overall energy is lost

-Mendeveel left gaps for undiscovered elements

Hess cycles
ΔH1 = ΔH2 + ΔH3
Hess’s Law states that the enthalpy change of a reaction is the same no matter what route was taken so the direct route on the diagram has the same enthalpy change as the indirect route

Enthalpy change of formation:

Ga(s) + As(s) --> GaAs(s)
solid because both their melting points are higher than 298K

Relative abundance 69.8

Heterogeneous catalyst - BDAC (I think - I cant remember what the letters were myself but I've seen a few people post that it was this)

Table:
Covalent, simple molecular
(Giant) ionic lattice, high melting point/soluble/ conducts electricity in solution and molten
Covalent

Table: Gallium-71: 31 protons, 31 electrons, 40 neutrons
Gallium-69: 31 protons, 31 electrons, 38 neutrons

Aint the second last question (first part) held by intermolecular bond? its cant be covalent if the question said it had a low melting or a low boiling point whichever it was and so was talking about the individual molecules.

[Venomilys]

(Original post by :)ella)
No, it's just the ones I could remember off the top of my head and one's people on this thread have mentioned. The only one I've deliberately missed is the one about clean burning fuels because I had no idea, couldn't see it in the textbooks or revision guides and there are too many definitions on Google!

for the disadvantage for hydrogen as a fuel, is it ok to say storing hydrogen as a fuel is expensive? It is factually correct, but I don't know if the markscheme will allow it.

Also this is what I said for the electron one:

electrons jump from higher energy level to lower one.
a photon of light is emited.
the line corresponds to the fequency of the photon emited.
They are lines because energy levels are discrete.
each spectrum is unique because the elements each have a unique electronic configuration.

How many out of 4?

[:)ella]

(Original post by the_future)
Aint the second last question (first part) held by intermolecular bond? its cant be covalent if the question said it had a low melting or a low boiling point whichever it was and so was talking about the individual molecules.

I thought the question was about the intramolecular bonds - so it would be simple covalent molecules (which have weak intermolecular bonds)

I could be wrong though because I don't have the actual paper

[:)ella]

(Original post by Ilyas)
for the disadvantage for hydrogen as a fuel, is it ok to say storing hydrogen as a fuel is expensive? It is factually correct, but I don't know if the markscheme will allow it.

Also this is what I said for the electron one:

electrons jump from higher energy level to lower one.
a photon of light is emited.
the line corresponds to the fequency of the photon emited.
They are lines because energy levels are discrete.
each spectrum is unique because the elements each have a unique electronic configuration.

How many out of 4?

To be honest I'm not totally sure about the hydrogen one because they're sometimes a bit funny about cost but it is factually correct so you could well get the marks.

And I'd say full marks for the emission spectrum - your first 4 points will get you the four and although the 5th is right, I'm not sure it's exactly what they're looking for but it's not wrong and you've already got your 4

Obviously I'm not an examiner though and who knows how their minds work!

[TheStudent.]

(Original post by SimpleGirl)
Yeah, I spent my time after the exam just sulking over the stupid mistakes but yesterday I got some very productive revision done so hopefully the rest of my exams go well.

And unfortunately, I don't think the methylbutane question was the only silly mistake I made so I'm certain it's not just one mark I've lost
Though, this exam has made me more aware now to make sure I don't let stupid things like not reading the question properly or 'I wasn't thinking' be an excuse to lose more marks next time.

Good luck with the rest of your exams!

Thats exactly what I did last year lol.

Ahhhh, well I wish you all the best! And you never know, the exam might've gone better than you thought

[s.aley]

(Original post by :)ella)
No, it's just the ones I could remember off the top of my head and one's people on this thread have mentioned. The only one I've deliberately missed is the one about clean burning fuels because I had no idea, couldn't see it in the textbooks or revision guides and there are too many definitions on Google!

i think for the clean burning fuels question you had to mention complete combustion

[cnj93]

Does anyone have the actual mark scheme to F331 and F332 for May/June 2012? Any help would be appreciated!

[hermi1]

I was just wondering, has anyone had this paper remarked and gone up?