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Reply 40
Why is that compared to methane, coal combusts to give ash? How do you know what combusts to give ash?
Reply 41
if anyone is wondering, you have to know the green and purple parts from storylines
Reply 42
Original post by TheNote
if anyone is wondering, you have to know the green and purple parts from storylines


What you basically need to know from Storylines is Octane number, Reforming, Isomerisation, Cracking and the use of catalysts in catalytic converters.
Can someone tell me how to answer an absorption spectrum question.
Original post by CeeBeeA
An electron will absorb a photon, become excited and will be promoted to a higher energy level. This creates the lines in the absorbtion spectrum.
The electromagnetic radiation absorbed is related to the difference in energy levels by Delta E = hv.

Should get you full marks.

Thankyou and for emission spectrum is it the same thing but electron drop back down to ground state em radiation?
Original post by Maishaashraf
Can someone tell me how to answer an absorption spectrum question.
come to think of it, I swear the questions are always about emission :/. I would include the following points: electrons absorb energy; and become excited (lol); and are promoted to a higher energy level.; the energy level are quantised- so electrons CANNOT be between levels ; the frequency/energy required to make a jump between levels is specific to each gap; (E=hf) ;so energy/frequency absorbed is specific; hence the distinct black lines. Don't forget to include E=hv/ E=hf somewhere in your answer-. there's usually a mark for including it in your explanation. I think these are the main points just modify and add/remove some bits to suit the question :smile:
Reply 46
Original post by JamesMartinez
What you basically need to know from Storylines is Octane number, Reforming, Isomerisation, Cracking and the use of catalysts in catalytic converters.


and zeolytes?
Reply 47
Original post by krisshP
Why is that compared to methane, coal combusts to give ash? How do you know what combusts to give ash?


hmmmm? which question are you reffering to.
Reply 48
Does this exam tend to mainly be resits? :/ I'm a little worried since in the thread for my biology exam seemed to be full of people who'd done it in January. My school decided to be cruel and not let us take January modules this year.
Hi guys, I just had a panic moment, could someone please remind me what maths we need to be able to do/know for this unit?
Reply 50
Original post by Kathiye
Does this exam tend to mainly be resits? :/ I'm a little worried since in the thread for my biology exam seemed to be full of people who'd done it in January. My school decided to be cruel and not let us take January modules this year.


I think it's half and half, a lot of colleges aren't doing their exams in Jan to see how the students do in the summer alone which will be the standard from next year.
Can someone please name a few limitations of the dot and cross models for the various bondings (i.e, ionic, covalent, dative covalent)
Reply 52
Original post by CallMeBatwoman
Hi guys, I just had a panic moment, could someone please remind me what maths we need to be able to do/know for this unit?


As in calculations we have to know?
moles
concetration
Q=c*m*deltaT
enthalpy changes using hess's law
gas volume (moles/24)
Original post by TheNote
As in calculations we have to know?
moles
concetration
Q=c*m*deltaT
enthalpy changes using hess's law
gas volume (moles/24)


Thank you so much! My teacher kept mixing up F331 and F332 today and I got so confused :s-smilie: thanks for your help! :biggrin:
Reply 54
Original post by CallMeBatwoman
Hi guys, I just had a panic moment, could someone please remind me what maths we need to be able to do/know for this unit?


1. Electron density
2. Bond enthalpies
3. Energy transferred (calorimeter)
4. Hess's Law
5. Percentage by mass
6. Empirical formulas
7. Half lifes
8. Relative abundance of isotopes
9. Calculations involving moles, volumes and mass
I think thats pretty much everything
Reply 55
Original post by CallMeBatwoman
Hi guys, I just had a panic moment, could someone please remind me what maths we need to be able to do/know for this unit?


I'm not too sure of what you mean exactly by 'maths', but I'll try to give you a list:

Working out relative atomic mass from a mass spectrum
Half lives
Reacting masses (eg working out number of moles of a reactant and using it to find the mass of a product)
Concentrations
Empirical Formulas
Gas volumes
Avogadro's Constant (sometimes they ask how many particles/moles there are)
c=λv
E=hv
Enthalpy changes using bond enthalpies (sometimes linked to the above three)
Enthalpy changes using enthalpy changes of reactions
Hess, using the above
Bond angles, if that counts. xD
E=mc(change in)t

I think that's all! In other words, a lot.
Reply 56
Original post by TheNote
I think it's half and half, a lot of colleges aren't doing their exams in Jan to see how the students do in the summer alone which will be the standard from next year.


Thanks! That's a little more reassuring. :biggrin:
Reply 57
Original post by Kathiye
I'm not too sure of what you mean exactly by 'maths', but I'll try to give you a list:

Working out relative atomic mass from a mass spectrum
Half lives
Reacting masses (eg working out number of moles of a reactant and using it to find the mass of a product)
Concentrations
Empirical Formulas
Gas volumes
Avogadro's Constant (sometimes they ask how many particles/moles there are)
c=λv
E=hv
Enthalpy changes using bond enthalpies (sometimes linked to the above three)
Enthalpy changes using enthalpy changes of reactions
Hess, using the above
Bond angles, if that counts. xD
E=mc(change in)t

I think that's all! In other words, a lot.


i don't think we need to know:
c=λv since that's a speed of light thing which we don't go near
Reply 58
in Jan the paper was grade boundries of exactly 80% are people hoping for a hard paper with low boundries or a an easier paper with higher boundries, i'm hoping for slightly harder so there is room for mistakes.
oh if anyone is interested this might be good to just run through before you leave for your exam, only annoying thing is you have to sign up to the website but it's pretty good :smile: http://getrevising.co.uk/revision-cards/ocr_chemistry_salters_f331#18