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AQA Chemistry Paper 2 AS Level 2016 Unofficial Mark Scheme

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Original post by SANTR
Do you know for the hydrogen graph Q, whether the vol decreased?


Yeah the hydrogen goes 1 sqaure lower
Reply 101
Original post by metrize
Yeah the hydrogen goes 1 sqaure lower


No I meant, the volume of the conical flask?
Also, why is it 1 square lower?
Original post by metrize
For the temperature difference you read between 2 readings, so 2x0.25=0.5 absolute uncertaintu.

They even told you the uncertainty for the reise of the temoerature was 0.5 why did you go double it again LMAO


its +- 0.5
for the question about a thin layer of Rhodium ect would the answer not be to provide a large surface area so the rate or reaction increases as there is more surface to react upon
Just added more answers to my original post. Check it out!
Original post by rumanah1
for the question about a thin layer of Rhodium ect would the answer not be to provide a large surface area so the rate or reaction increases as there is more surface to react upon


Quite a few people wrote that. Personally I wrote that too. But it doesn't really make sense.
Reply 106
Original post by DaVinciGirl
Just added more answers to my original post. Check it out!


Isn't the last MPC C and not D?
For the Z isomer one I thought Z meant the same groups were together and therefore isn't the diagram drawn an E isomer?! Not sure though! ☺️
Original post by SANTR
Isn't the last MPC C and not D?

It is but the the last combination of answers were someone else's so some are incorrect :smile:
Original post by Anna1909
For the Z isomer one I thought Z meant the same groups were together and therefore isn't the diagram drawn an E isomer?! Not sure though! ☺️

The diagram I drew is the Z isomer, because the highest priority group for the right is Ch2Ch3 and on the left is Ch3 which is both on the same side. I think you got confused with the two ch3 and put them both in one side :smile:
Reply 110
Original post by DaVinciGirl
Anymore answers are welcome and feel free to correct any mistakes. Thank you!

1.1 Kc=[product]/[Reactant 1][Reactant 2]
Unit- mol^-1dm^3

1.2 10.5 mol^-1dm^3

-Z-isomer (ignore my awful drawing, I tried doing it on my macbook)
Screen Shot 2016-06-10 at 18.43.05.png

-Equation for Cl free radical and ozone layer
Cl.+ O3 ---> ClO.+ O2
ClO.+ O3 ----> 2O2 + Cl.
-Drawing chloropentafluroethane
Screen Shot 2016-06-10 at 16.23.33.png
-Why those the molecule (one without Cl) not contribute to ozone depletion? Because doesn't have a C--Cl bond so no chlorine free radical is made.
-Why does greenhouse gases like Co2 absorb a lot IR? They have bonds that have high bond enthalpy

-Fluorine free radical and CH3CF2 (Check the formula I think it was that?)
Propagation Step 1: .F + CH3CF2 ----> .CH2CF2 + HF
Propagation Step 2: .CH2CF2 + F2 ---> CH2CF3 + .F

-Number of molecules + Avogadro constant question? 1.01 x 10^25

-Isooctane? Nomenclature- 2,2,4-trimethypentane
-Name how to separate Isooctane and octane and how?
Distillation and you heat the conical flask with temperature above 99 degrees so Isooctane compound vaporises but the other compound remains liquid. Condense in a cooling jacket.

-Oleic acid testing for unsaturated
Bromine water and Observation from orange to colourless

-Enthalpy change of Combustion of methanol- -307 kJmol^-1
-Why enthalpy change lower- neglecting the specific heat capacity of the calorimeter
-Uncertainty- 0.5/38*100= 1.31%
-Why Uncertainty of 0.5 is okay?
-Heat change for ethanol 11760 KJ maybe 11800KJ as it's in 3sf (I have a blurry memory about this one)

-Write the complete combustion of octane?
C8H18 + 12.5O2 -> 8CO2 + 9H2O
-Catalyst how it works
Lowers activation energy by providing an alternate route to a reaction
-How does NO and CO react?
2NO + CO ----> N2 + CO2
-Thin layer catalyst maybe because it's more cost effective and catalyst doesn't get used up during reaction so you don't need thick layer.

-Why are the two compound impossible to distinguish in precise mass spec?
Both has the same number of atoms for each element so same precise molecular mass.
-Infrared Radiation: O-H bond and 3230-3550 cm^-1

6 Marker: Alcohol (hydrogen bonds, permanent dipole dipole, van der waals) Aldehyde (permanent dipole dipole and van der waals) and alkane (van der waals)

7 Marker electrophilic addition
Outline Mechanism: arrow from double bon to H(delta plus) arrow from bond H---Br to Br)
Tertiary Carbonation ion is more stable than secondary carbocation because alkyl groups is electron releasing and stabilises the carbocation. So most stable carbocation is formed more. 3bromo is more stable than 2bromo.

-Excess find moles of both and magnesium has more moles than the other compound so more magnesium is needed for a the first compound to react.
-Graph- I drew it lower and slower because there's fewer moles of reactants. Should be lower and quicker according to other because the concentration increased.

-Acidified potassium dichromate display formula both ketone and carboxylic acid and equation
Screen Shot 2016-06-10 at 16.48.19.png
CH3CH(OH)CH2OH + 3[O] CH3COCOOH + 2H2O

-Reflux Apparatus
Screen Shot 2016-06-10 at 16.44.46.png

-AntiBumping Granules

-What is the structure when not in excess?
Aldehyde and ketone one

Multiple Choices
-orange to red, aldehyde one with cho-
-Increase Temp- makes KC increase and yield increase C
-Last question multiple choice is C
-The C,H,O is B- ethanoic acid
-Nucleophilic Substitution
-Total Equilibrium moles 18
-The Cyclohexene general formula- CnH2n-2
-Cracking equation A
-Percentage yield is 86.6%
-Polymer question Which is the alkene- D
-Maxwell Graph- C That number of molecules of E>Ea
For the first 10 questions these may be the answers credit to @quiin f : CDDBAADCAB
Answers to 15 MCQ in order credit to @britishtf2 :
CDDABBDCABCDCBC


I got 1.32% for the percentage error question is that ok?
Original post by DaVinciGirl
The diagram I drew is the Z isomer, because the highest priority group for the right is Ch2Ch3 and on the left is Ch3 which is both on the same side. I think you got confused with the two ch3 and put them both in one side :smile:
yup! Damn I thought I had got it right 😂 It was only one mark I guess! Thanks it makes sense!
Original post by NimcoA
I got 1.32% for the percentage error question is that ok?

I believe you're right. I just checked on the calculator, I'll change it.
Reply 113
Original post by DaVinciGirl
It is but the the last combination of answers were someone else's so some are incorrect :smile:


Thanks for clarifying :smile:
Regarding the H2 volume Q, why does the volume decrease?
Reply 114
Original post by DaVinciGirl
Anymore answers are welcome and feel free to correct any mistakes. Thank you!

1.1 Kc=[product]/[Reactant 1][Reactant 2]
Unit- mol^-1dm^3

1.2 10.5 mol^-1dm^3

-Z-isomer (ignore my awful drawing, I tried doing it on my macbook)
Screen Shot 2016-06-10 at 18.43.05.png

-Equation for Cl free radical and ozone layer
Cl.+ O3 ---> ClO.+ O2
ClO.+ O3 ----> 2O2 + Cl.
-Drawing chloropentafluroethane
Screen Shot 2016-06-10 at 16.23.33.png
-Why those the molecule (one without Cl) not contribute to ozone depletion? Because doesn't have a C--Cl bond so no chlorine free radical is made.
-Why does greenhouse gases like Co2 absorb a lot IR? They have bonds that have high bond enthalpy

-Fluorine free radical and CH3CF2 (Check the formula I think it was that?)
Propagation Step 1: .F + CH3CF2 ----> .CH2CF2 + HF
Propagation Step 2: .CH2CF2 + F2 ---> CH2CF3 + .F

-Number of molecules + Avogadro constant question? 1.01 x 10^25

-Isooctane? Nomenclature- 2,2,4-trimethypentane
-Name how to separate Isooctane and octane and how?
Distillation and you heat the conical flask with temperature above 99 degrees so Isooctane compound vaporises but the other compound remains liquid. Condense in a cooling jacket.

-Oleic acid testing for unsaturated
Bromine water and Observation from orange to colourless

-Enthalpy change of Combustion of methanol- -307 kJmol^-1
-Why enthalpy change lower- neglecting the specific heat capacity of the calorimeter
-Uncertainty- 0.5/38*100= 1.32%
-Why Uncertainty of 0.5 is okay?
-Heat change for ethanol 11760 KJ maybe 11800KJ as it's in 3sf (I have a blurry memory about this one)

-Write the complete combustion of octane?
C8H18 + 12.5O2 -> 8CO2 + 9H2O
-Catalyst how it works
Lowers activation energy by providing an alternate route to a reaction
-How does NO and CO react?
2NO + CO ----> N2 + CO2
-Thin layer catalyst maybe because it's more cost effective and catalyst doesn't get used up during reaction so you don't need thick layer.

-Why are the two compound impossible to distinguish in precise mass spec?
Both has the same number of atoms for each element so same precise molecular mass.
-Infrared Radiation: O-H bond and 3230-3550 cm^-1

6 Marker: Alcohol (hydrogen bonds, permanent dipole dipole, van der waals) Aldehyde (permanent dipole dipole and van der waals) and alkane (van der waals)

7 Marker electrophilic addition
Outline Mechanism: arrow from double bon to H(delta plus) arrow from bond H---Br to Br)
Tertiary Carbonation ion is more stable than secondary carbocation because alkyl groups is electron releasing and stabilises the carbocation. So most stable carbocation is formed more. 3bromo is more stable than 2bromo.

-Excess find moles of both and magnesium has more moles than the other compound so more magnesium is needed for a the first compound to react.
-Graph- I drew it lower and slower because there's fewer moles of reactants. Should be lower and quicker according to other because the concentration increased.

-Acidified potassium dichromate display formula both ketone and carboxylic acid and equation
Screen Shot 2016-06-10 at 16.48.19.png
CH3CH(OH)CH2OH + 3[O] CH3COCOOH + 2H2O

-Reflux Apparatus
Screen Shot 2016-06-10 at 16.44.46.png

-AntiBumping Granules

-What is the structure when not in excess?
Aldehyde and ketone one

Multiple Choices
-orange to red, aldehyde one with cho-
-Increase Temp- makes KC increase and yield increase C
-Last question multiple choice is C
-The C,H,O is B- ethanoic acid
-Nucleophilic Substitution
-Total Equilibrium moles 18
-The Cyclohexene general formula- CnH2n-2
-Cracking equation A
-Percentage yield is 86.6%
-Polymer question Which is the alkene- D
-Maxwell Graph- C That number of molecules of E>Ea
For the first 10 questions these may be the answers credit to @quiin f : CDDBAADCAB
Answers to 15 MCQ in order credit to @britishtf2 :
CDDABBDCABCDCBC


Idk but isn't the MPC On Maxwell-boltzmann the most probable energy or is that another Q I can't remember.
hey are we going to put any marks on these ? or too hard to remember sorry if thsts too much to ask just wondering
Reply 116
Was this paper hard?
Original post by XzaraX
Was this paper hard?


Actually think it was an alright paper, especially compared to paper 1.
Original post by Anna1909
For the spectroscopy peak question I think you could also have the C=C bond and the range ☺️ I think

That's what I put
Reply 119
Original post by spidle
Actually think it was an alright paper, especially compared to paper 1.


Does anyone have an unofficial mark scheme with questions and answers together of the whole paper?

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