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2016 AQA Chemistry C2 - Unofficial Mark Scheme 2016

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for the 6 marker, i somehow got 50 for the amount but justified the answer by using all the information from the graph such as the price and the run off into the rivers and lakes, I wrote quite a lot an since it was 6 marks is there any chance of me getting at least a few marks?

Reply 161

steezus

Original post by Naco88

Notice: I would like to apologise on my own behalf about getting a question on PH wrong. I put 0 instead of 7. I typed this on my phone so there was bound to be a mistake however I have now checked everything else and it all seems right.

Hello. Welcome to my AQA Chemistry C2 Unofficial mark scheme! Due to the success of my other mark scheme for AQA Biology which got 40k views I will happily do another and look forward to seeing how you guys found the exam.

This mark scheme is made completely by people who have done the exam so is written purely from knowledge. We will try and get the questions in the right order however putting marks next to each is very hard so please do not request this. If you remember a question we forgot then feel free to comment it below or contact me on twitter (@NacoRBLX) and I will be sure to add it.

This mark scheme is not official and was made purely from what we saw in the exam.

AQA C2 Higher - Unofficial Mark Scheme (Updated Regularly) (Should have a few questions of foundation)

Note: Not all the questions are complete

1. Question on Temperature Change
a) 5.75 (do not include the anomaly)
b)
c)
d) How could you change the apparatus to get more accurate results? Use a digital thermometer. It is more accurate.
2. Question on Fertilisers
What is the PH after being neutralized? 7
Percentage by mass: 14+1+1+1 = 17 (14/17) x 100 = 82%
6 Mark Question about a farmer using ammonium nitrate on his crops. The best value to use was around 200kg because the lowest possible amount went into nearby lakes and it produced the maximum profit. Values between 200kg and 300kg would all probably be accepted. The examinors want to see that you can compare values on all graphs and find one which suits them all. Doing this should get you most of the marks.
3. Question on Particles and Nano Particles
Why are nano particles good catalysts? They have a large surface area to volume ratio.
Put the dots/crosses in the diagram to resemble electrons. Put 2 dots/crosses in the overlapping bits and 6 outside of it. There should be 8 in the outer shell of oxygen so getting them in the wrong places but drawing 8 dots/crosses should get you 1 mark out of 2.

4. Reaction experiment (cross under flask)
Why did the liquid go cloudy? Sulfur was produced (see equation) which dissolved in the water.
What should she keep the same? The amounts of each substance used. The person looking at the cross.
How could she do it with a temperature of 5 degrees? Cool the liquid
5. Question on electrolysis (Magnesium Chloride)
Why do the molecules need to be melted or dissolved in water?
The particles need to be able to move so they can get to the electrodes. This also separates them.
Why does magnesium form at the negative electrode?
It is M²⁺so it will be attracted to the negative electrode. It will then gain 2 electrons and therefore no longer be an ion.
In experiment 2, magnesium did not form at the negative electrode, why?
The magnesium chloride was dissolved in water so hydrogen atoms are present. These are less reactive than magnesium so will form.
6. Question on materials
How does copper conduct electricity? It has free electrons in its structure which can flow through when a current is applied.
Why is diamond very hard to break? Diamond is hard because it has lots of strong covalent bonds which are hard to break.
Why would you use thermosetting polymers in pan handles? They are strong and heat resistant. They have a high melting point.

Predicted grade boundaries will come soon.

Note: The question parts may not be in the right order.

This is a mix of my answers and those of the community but they are not guaranteed to be correct.
Grade Boundary Predictions

These are completely my predictions, we have decided that it was a fairly
easy paper so our boundaries are fairly high.

A* - 49 marks

A - 42 marks

B - 35 marks

C - 29 marks

If you did the B2 exam on Friday, we have the mark scheme for that as well!
http://www.thestudentroom.co.uk/showthread.php?t=4155717

29 marks for a C seems pretty high, highest its been in the past is 21

Reply 162

Oasis61

Original post by Meegan543210

it said PURE water didn't it? And it doesn't have ions in it anyway... So I don't think you have to write about simple molecular substances it was one mark

I wrote it doesn't have any delocalised electrons?? Would that get any marks

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Reply 163

Michelle15

For question 1 on how to make the results more accurate, i said stirring it so all the substance (i think it was salt) can be dissolved completely into the solution. Everyone is saying its a digital thermometer to obtain more accurate results. Please can someone tell me if my answer is correct?! As in prewvous pass papers they have accepted things such as stirring and using a lid.

Reply 164

username2283975

Original post by strikeh

Look familiar :confused:

http://filestore.aqa.org.uk/subjects/AQA-CH2HP-QP-JAN13.PDF

yes. i done both 2013 papers, 2014 and 2015. I marked all of them and in the exam i remembered all the answers from the mark scheme

Reply 165

Wisbey

'How could she do it with a temperature of 5 degrees? Cool the liquid'

I'm pretty sure on my exam paper is stated that the temperature was the control variable however it was going to be changed. It then asked what should now be changed, the concentration of the acid.

(edited 7 years ago)

Reply 166

k2sigma

Original post by Frankie___

Will I still get the marks if I said the answer was 82.35%? I wrote next to it to 2 d.p.

Yep! Thats what i did.. They definitely will because unlike 82%.. 82.35% is a suitable level of degree and writing 2dp next to it will let examiner know.