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AQA AS 2016 - CHEM1 (Resit) Unoffical Mark Scheme

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Reply 120
Original post by EmmaHarvard
The shape one was the total marks and the scoring points??

It was 6 marks for the whole table, probably 3 marks for shape 1 (SF6) and 3 marks for shape 2 (SF4) eventho u didn't have to name shape 2 but it was quite a complex shape and bonding angle was hard to figure out.
Original post by Pluto98
Hello there,
I think the questions asked for 2 conditions :/, but did you put thermal cracking though?
I've put high temp (700 degrees)
High pressure ( >1000kPa)
i put thermal cracking and condition high temp
Original post by SirRaza97
If anyone remembers I will add them :smile:


Thanks 🙂
Original post by SirRaza97
EDIT: Thanks to everyone who has helped in this thread. If anyone can remember the marks for each question I will add them in for you guys! Also the Bold stuff after some thought are probably the correct answers or something along the lines of it. Good luck to everyone in the rest of their exams

Here is my unofficial mark scheme. Anything in bold I am not sure if it's right. So if you have any idea then please tell me so i can add it! If i have missed anything out then aslo let me know!

Section A

1.
a) Relative Atomic mass Definition
b) Magnetic Field
c) - Ions accept electrons -Current is formed which is proportional to abundance
d) Something like 28.065 for the RAM
e) Similarity= Peaks still at original m/z values becuase +1 ions are still formed/
same relative abundance (or same height of peaks) because same sample is used so similar amount of the isotopes are present
-Difference - Peaks at half the m/z values becasue high energy electrons will produce +2 ions

2. (Can't rmember what topic this was. I think it was about Van Der Waals)
a) -Electron Density randomly shifts -Creating areas of +ve and -ve charge on molecule - Attraction between molecules which is intermolecular force/VDW
b) O-H bond big electronegative difference allows for hydrogen bonds. Hydrogen bonds are stronger than VDW.
c) Fractional Distiallation will sperate these
d) The Se molecule is larger. This means the VDW forces are stronger between molecules

3. (Questions about Alkanes?)
a) Group is alkane
b) 2,2,4 - trimethylpentane (might accept 2,4,4 - trimethylpentane)
c) C8H18 + 12.5O2 ------> 9H2O + 8CO2
d) but-1-ene
e) C14H30
f) Thermal Cracking. High temp and high pressure
g) Isomers question. Chain isomer = H2C=C(CH3)2 Postion isomer = But-2-ene Functional Isomer = Cyclic Alkane so cyclicbutane

4. (The weird reactions and the shapes question?)
a) Balancing equation I couldn't remember
b) Cu2(OH)2CO3 + 4HCl -----> 2CuCl2 + 3H2O + CO2
c) Effervescense
d) Cu3O8H2C2 or in the structural form
e) Shapes question - SF6 = Octohedral , 90 degrees -SF4 = See-Saw shape. Lone pair on the horizontal plane. Angles 90, 120 or 180 degrees. Probably will accept -2.5 degrees off each angle.

Section B

5. (Period 3 stuff)
a) - Ionisation energies increase -Increasing proton number - Similar Shielding -Attraction between outer electron and nuclues gets stronger -The bigger nuclear charge reduces atomic radius (I don't think this point is needed)
b) -Silicon has highest melting point. -Because of macromolecular/Giant covelant structure. -Strong covelant bonds throughout structure. -Requires high amounts of energy to break.
c) The elements that you could say were Aluminuim because removing electron from 3p shell and Sulphur because of pair repulsion.
d) -Element Y is Sulphur. -Large jump in eneries from 6th to 7th ionisation enegies -So 7th electron in inner shell so sulphur must be the element Y.

6. (Calculations)
a) 0.113m3 (3 sig figs needed)
b) 1065 Kg or 1.065x106 g
c) Percentage yield = 49.3%
d) Method 1 because its 100% atom economy. Only producing one product.


I got something different for 4d ( Cu2(OH)CO3 ) i thought you had to put it in that form :?
Reply 124
Original post by fasdaman2212
I got something different for 4d ( Cu2(OH)CO3 ) i thought you had to put it in that form :?


I dont think it matters
Reply 125
Original post by jaymistry233
The answer in the 2010 past paper refered to the changing of velocity of the cations by altering the strength of the electric field generated by the negatively charged accelerating plates so that a spectrum of ions of different m/z ratios could be collected. The question asked how a full spectrum could be observed, changing the electric field strength was one of many factors.


Electric field accelerates, hence the reference to velocity, the magnetic field deflects. I'm afraid that you're wrong
Reply 126
Thanks for making this btw,
does anyone remember the actual wording of the question 5c? You mentioned two answers, aluminium and sulphur and i only wrote sulphur, bc paired orbital, thinking i read it wrong..

Also for the successive ionisation energies i think i wrote oxygen instead of sulphur bc again i'm an idiot that doesn't read questions properly, i explained it and stuff, do you reckon i'll get partial marks? Or none cause they asked for period 3 properties? Thanks
Original post by hp707
Thanks for making this btw,
does anyone remember the actual wording of the question 5c? You mentioned two answers, aluminium and sulphur and i only wrote sulphur, bc paired orbital, thinking i read it wrong..

Also for the successive ionisation energies i think i wrote oxygen instead of sulphur bc again i'm an idiot that doesn't read questions properly, i explained it and stuff, do you reckon i'll get partial marks? Or none cause they asked for period 3 properties? Thanks

It was something in the lines of
Name one element in period 3 which deviates from.this general trend
If you get the element wrong.. It is still possible to get marks..as sometimes the explanation may be independant of the initial answer
Reply 128
Original post by fasdaman2212
It was something in the lines of
Name one element in period 3 which deviates from.this general trend
If you get the element wrong.. It is still possible to get marks..as sometimes the explanation may be independant of the initial answer


Thanks! So in terms of 5c will i get the mark as I did mention one? (Sulphur) The wording of this unofficial markscheme made me think i shouldve mentioned two?..
Reply 129
Original post by hp707
Thanks! So in terms of 5c will i get the mark as I did mention one? (Sulphur) The wording of this unofficial markscheme made me think i shouldve mentioned two?..


No you only had to mention one but there are 2 possiblities
Reply 130
Original post by SirRaza97
No you only had to mention one but there are 2 possiblities


sick, thanks!


Nice to know I'm not alone.

Original post by SirRaza97
Haha good chem5 application. That would be pretty hard for an AS sudent xD


Yeah, but they asked for cucl2 not cucl4 :frown: This is like the stupid mg2n3 vs mgn6 question all over again lol.
How the hell did I get the volume at 0.451m3, ffs
Wish someone had the paper so i could see
Original post by Dankailen
how many marks do i lose? i did the correct calculations


You must have divided by the combined masses of all isotopes to obtain the answer of 32. You must divide them by the total abundance, which in the case was 100. You will most likely lose 1 or 2 marks.
What do people think the grade boundaries will be like for an A? I reckon this paper was a bit harder than last years so I'd guess 55 for an A.
Original post by Danny786
How the hell did I get the volume at 0.451m3, ffs
Wish someone had the paper so i could see


I got the same answer as you, we basically forgot to multiply the moles of Phosphorous by 4 as the molecule was P4, we will probably get 2-3/4 marks if you got everything else right, as the method marks carry over.
Original post by TheLifelessRobot
What do people think the grade boundaries will be like for an A? I reckon this paper was a bit harder than last years so I'd guess 55 for an A.


53-55, 53 was for last year.
Original post by Studious_Student
53-55, 53 was for last year.


Last year was 57 for an A.
Original post by TheLifelessRobot
Last year was 57 for an A.


Oh shoot I apologise lol, read it incorrectly -_- I hope it's around 55 none the less, I feel like I did pretty well except for losing around 10-12 marks.
Crap I just realised that I didn't draw all the bonds for the isomers question. It asked for the displayed formula :frown:

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