OCR F321 - 23rd May

it was definitely added to both, i'm with ufo here

so did you write 2 for your answer?

Q8B) Disproportionation of chlorine, +5 -> +7 and +5 -> -1
TOTAL MARKS = 1

Q8C) -It's both oxidised and reduced simultaneously.
TOTAL MARKS = 3

It definitely was - anyways, I've lost 3 marks already so DAMN!

in test tube A, the HCl was added to the MgO
test tube B hcl was added to MgCO3

Zn has a plus +1 charge
Po4 has a -3, think about phosphoric acid, H3PO4,

So it's Zn3PO4

Originally Posted by broken_glass_heart
whilst its still fresh in our minds, lets have a mark scheme so people know where they went wrong..please feel free to add to it or amend it if am wrong...

Q1) Proton = +1 charge, mass =1, in NUCLEUS
Neutron = 0 charge, mass = 1 in nucleus
Electron = _1 charge, mass 1/2000, on outer shell
TOTAL MARKS = 1

Q2) The first ionisation energy is the energy required to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions.
TOTAL MARKS = 3

Q3) 2p orbital + 2 electrons
3s subshell = 2 electrons
4th shell = 32 electrons
TOTAL MARKS = 3

Q4) periodicity = The trends/patterns shown be elements across a period
TOTAL MARKS = 1


Q5) X, 14, 6 was C
ion with -3 charge with structure of neon was nitrogen
The element with the lowest first ionisation energy was Sodium/Na
Lowest 3rd ionisation energy was Aluminium
The last bit with the 6 ionisation energies shown below was Mg
TOTAL MARKS = 5

Q7A) MgCO3 -------> MgO(S) + CO2 (g)
TOTAL MARKS = 1

Q7B) PRODUCT OF TEST TUBE A = MgO + CO2
PRODUCT OF TEST TUBE B = MgCl2 + CO2 + H20
TOTAL MARKS = 2

Q7C) SIMILARITIES = Effervescence seen as CO2 given off in both reactions
DIFFERENCES = A white solid precipitate of MgO formed in test tube A, but no solid precipitate in test B.
TOTAL MARKS = 2

Q8A) Sodium Chlorate (V)
TOTAL MARKS = 1


Q8B) Disproportionation of chlorine, +5 -> +7 and +5 -> -1
TOTAL MARKS = 1

Q8C) -It's both oxidised and reduced simultaneously.
TOTAL MARKS = 3


Q9a) Question about how you know a salt is produced:
The H+ ion in the HCl acid is replaced by the metal ion (Na+?)
TOTAL MARKS = 2


Q9b) Product formed is Zn3(PO4)2
TOTAL MARKS = 1


Q10) Why not use Chlorination:
Many answers from:
- chlorine forms chlorinated hydrocarbons which are carcinogenic
- chlorine can form toxins
Why use chlorination?
Answer: Benefits outweigh the risks. this has been proved by scientists
TOTAL MARKS = 2


To be continued....


The one with the calculations finding out about the percentage of that chemical in that drug of 500mg.
-The percentage at the end was something like 93-94% - can't remeber what it was exactly.

thats right only if it talking about from the very 1st s orbital and adding up to it..
but if u minus s^2 from the your first answer, its = 6 ELECTRONs

do you think me saying a) CO2 given off b) solid disappears in 2 but not in one..

because it said what would they observe...?

damn i didnt read the question properly

Yh, that's exactly what i put! Hope it's right

I read it twice....i couldn't make it out whether it was
from the beginning or not.....