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# AQA GCSE Chemistry Unofficial mark scheme

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1. (Original post by dhruvap)
I reckon i've got 54-55 with harsh marking. By the way 20.3 is a wrong answer! You are meant to place it in 2 decimal figures (from the graph) for 2 marks. So in reality the answer is 20.30 not 20.3. How do I know this? 1) It was a 2 marker. 2) Our teacher is an AQA part time examiner and that is what he told us.
no lol, it was a 2 marker yh, 1 mark for the working out and 1 mark for the answer and the answer was 20.3
2. (Original post by ScienceFantatic)
Was that definitely question 5?
Most of your points in the last question was correct. The only thing that is wrong is that the boiling point dosent increase, the melting point does. And for the 6 marker even though most of the natural gas is made from methane, there are still hydrocarbons in the natural gas.
3. (Original post by dhruvap)
For all the people that wrote 20.3... The table had answers written in 2 decimal places, e.g. 24.74, 26.56 .... Therefore answer of the mean but be in two decimal places. This is why it was a 2 MARKER. The calculator showed 20.3 but you are meant to apply knowledge of the table and see that answer must have 2 decimal places. If anyone has proof from past papers I would like to see.

This is what my teacher said,(aqa examiner who received mark scheme at lunch) and I've also realised that yes this is true. (I made same mistake).
20.3 is exactly the same as 20.30 it makes no difference, im also sure the mark schemes wouldnt even have been given out yet

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4. (Original post by dhruvap)
For all the people that wrote 20.3... The table had answers written in 2 decimal places, e.g. 24.74, 26.56 .... Therefore answer of the mean but be in two decimal places. This is why it was a 2 MARKER. The calculator showed 20.3 but you are meant to apply knowledge of the table and see that answer must have 2 decimal places. If anyone has proof from past papers I would like to see.

This is what my teacher said,(aqa examiner who received mark scheme at lunch) and I've also realised that yes this is true. (I made same mistake).
5. The
(Original post by blueribbons99)
20.3 is exactly the same as 20.30 it makes no difference, im also sure the mark schemes wouldnt even have been given out yet

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E
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6. You know for the question on sub atomic particles i didnt put +1, -1 and 0, i just put positive, neutral and negative charge. Will i still be awarded the marks?
7. im so lucky that all my isa grades are A or above, i guess i will need to get A*s all the 1's and 2's and a high a for the 3's in order to get A* for all 3 of em
8. (Original post by dhruvap)
For all the people that wrote 20.3... The table had answers written in 2 decimal places, e.g. 24.74, 26.56 .... Therefore answer of the mean but be in two decimal places. This is why it was a 2 MARKER. The calculator showed 20.3 but you are meant to apply knowledge of the table and see that answer must have 2 decimal places. If anyone has proof from past papers I would like to see.

This is what my teacher said,(aqa examiner who received mark scheme at lunch) and I've also realised that yes this is true. (I made same mistake).
Also, the exam was after lunch. So AQA would be out of their minds to give a teacher-examiner the mark scheme before the actual exam took place. Just a bit of common sense was lacking in that lie
9. (Original post by Mathsisfun69)
You know for the question on sub atomic particles i didnt put +1, -1 and 0, i just put positive, neutral and negative charge. Will i still be awarded the marks?
Most likely however if you mentioned the electron you won't receive any marks because you didn't answer the question.
10. (Original post by bledzcool)
Most of your points in the last question was correct. The only thing that is wrong is that the boiling point dosent increase, the melting point does. And for the 6 marker even though most of the natural gas is made from methane, there are still hydrocarbons in the natural gas.
Ah I wrote melting point in my exam paper buy I want sure. I'm not sure sure what you're getting at with the 6 marker.
I wrote Lid to prevent gasses escaping LOOOL such a fail
I did aswell, is that wrong?
That same question was on a C3 paper a few years ago and the answer was a lid to prevent heat escaping
12. (Original post by iamhasana;[url="tel:64971431")
64971431[/url]]Most likely however if you mentioned the electron you won't receive any marks because you didn't answer the question.
No, i didnt add the electrons, i'm honestly not too sure why i added it here lmao. Anyways, thanks for the reassurance. I think i've got around 37 marks or more. I harshly marked myself
13. (Original post by mrh7)
I did aswell, is that wrong?
That same question was on a C3 paper a few years ago and the answer was a lid to prevent heat escaping
I put it as well I thought I was right?

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14. (Original post by blueribbons99)
I put it as well I thought I was right?

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I said decrease surface area of hydrocarbon fuel is this right?

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15. (Original post by z_o_e)
I said decrease surface area of hydrocarbon fuel is this right?

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No because the fuel burnt was liquid so how would you do that? and that wouldn't mean the thermometer would give a more accurate measurements unfortunately
16. one mark for showing the working out and one mark for answer.
How can you round a number that has one decimal to two decimal places?

20.3 cannot be rounded to to 3 significant figures, as there is no 4th number.
The information provided was in whole numbers and thi is why it did not come up as a recurring decimal.
17. (Original post by blueribbons99)
I put it as well I thought I was right?

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Yeah I think it is
18. (Original post by ScienceFantatic)
If anyone wants to help filling it out o can remember specific questions, post here
Do you think I would get a mark for saying 'Heat' instead of 'High temperatures'?
19. (Original post by ScienceFantatic)
This is for the higher tier

Question 1
Spoiler:
Show
Electron shell: 2,3( 1 mark)
Nucleus( 1 mark)
Neutron is uncharged, proton has a charge of +1 ( 3 marks)

Not in form 2,8,8, has 1,8. Neon has 10 electrons, the structure had 9 electrons, doesn't have a full outer shell but neon does (
3 marks)
Question 2
Spoiler:
Show
Tick box: copper oxide(1)

20.3(2 marks)

Digital thermometer, more precise and not subject to human error
Beaker insulated( any forms of insulation really:lid, wool etc.(2)

Carbon particles produced( particulates)Insufficient oxygen or incomplete combustion(2)

Best fuel because it produces least smoke/ burns the most cleanly. Produces the most energy per g(2)
Question 3
Spoiler:
Show
Only product water
Renewable
Provides more energy
No co2 or s02 released

Hydrogen is explosive
Hard to store because it is a gas
From natural gas( methane which is a greenhouse gas)
Engines need to be converted( 6 marks)

Thermal decomposition(1)

Question on potassium carbonate: doesn't fully thermally decompose, co2 not released, Bunsen burner temperature is not high enough( 3 marks)

Reactivity question: the lower the metal on the reactivity series, the easier it is broken down(2)
Question 4:
Spoiler:
Show
Conditions for cracking: high temperatures/400-700 degrees and a (hot) catalyst/Aluminium Oxide (2 marks)

Fermentation question: sugar is dissolved and yeast is added to make ethanol(2)

Ethanol question: ethene is reacted with steam at high temperatures and catalyst(2)

Advantages and disadvantages of crude oil vs plants: Crude oil is a continuous process so faster. The ethanol produced from crude oil is more pure than plants and biofuel.Crude oil is more widely available, crude oil is more reliable.

Non renewable, co2( global warming), SO2

(4 marks)
Question 5
Spoiler:
Show
metal ores are ores which contain enough of the metal to be worthwhile extracting( 1 mark)

It is converted to steel because cast iron is brittle or to make it stronger
Steel has more uses
Corrosion resistant
( 2 marks)

2Fe2O3+ 3C = 4Fe+ 3CO2( 2 marks) 1 mark for correctly balaned, another for realising Iron was made.

It is not sent to landfill because this takes up space and causes pollution
It is not reused as it might have lost its strength and become unstable. It is recycled because it saves energy being used. Conserves raw material. Less Quarrying needed.
3 marks)

Question on distillation: Heat mixture between 80-99 degrees, the ethanol evaporates, cools and condenses to form pure ethanol and then raise temperature to 100 when all ethanol has evaporated to do the same to water. Maybe a mark for saying ethanol has a lower boiling point than water.( 3 marks).

Question on carbon neutral: carbon dioxide is a greenhouse gas
This takes up CO2 when it grows in photosynthesis
The same amount is released when biofuel or oils are burned
So no overall increase in CO2
Continuous Carbon Cycle(3)

Last question on hydrogenation; 60 degrees, reacted with hydrogen, nickel catalyst, double bonds converted into single bonds, increasing melting point, done so that's it's a solid at room temperature for a thick, spreadable consistency (5)
Random ones:
Spoiler:
Show
Mark somewhere for completing drawing of the alkane(1)

Bromine goes colourless somewhere(1) Clear is not acceptable.
Took me a while to make so any rep would be much appreciated . I hope this helped you all, I was getting impatient with it not being made in time so I made my own.

For Q3, reactivity series, I wrote the answer you have but because I was rushing I also accidentally said 'the more reactive it is, the easier it is' instead of less reactive. Do I lose marks for the right answer for writing the end part?
20. (Original post by Prxya_K)
For Q3, reactivity series, I wrote the answer you have but because I was rushing I also accidentally said 'the more reactive it is, the easier it is' instead of less reactive. Do I lose marks for the right answer for writing the end part?
that is exactly what I ended up doing such easy 2 marks

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Updated: October 26, 2016
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