2016 AQA GCSE Chemistry Unofficial mark scheme 2016

Question 1
Electron shell: 2,3( 1 mark)
nucleus( 1 mark)
( +1), electrons( -1), neutron is uncharged( 3 marks)

Not in form 2,8,8, has 1,8Boron has 10 electrons, the structure had 9 electrons( 3 marks)

Question 2
Tick box: copper oxide(1)

20.3(2 marks)

Digital thermometer, more precise and not subject to human error
Beaker insulated(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
Advantages of hydrogen
Only product water
Renewable
Provides more energy
No co2 or s02 released

Disadvantages
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: anyone got suggestions? Think my answer is wrong (2 marks)

Question 4:
Conditions for cracking: high temperatures and a hot catalyst(2)

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, crude oil is more widely available, crude oil more reliable and things are set up for crude oil fractions

Non renewable, co2( global warming), SO2

(4 marks)

Question 5
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)

4Fe2O3+ 3C = 4Fe+ 3CO2( 2 marks) - This ans is now correct, as iron is not diatomic

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. Saves energy being used. Conserves raw materials
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( 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, nickel catalyst, double bonds converted into single bonds, increasing boiling point, done so that's it's a solid at room temperature for a thick, spreadable consistency (5)

58 marks

yeah I think you basically had to describe fractional distillation but with ethanol and water instead of crude oil

Would I get aluminium oxide catalyst?

Changed

Changed

For the distillation question, do you reckon heating it all to over 100 and then cooling it in stages will get marks?
Both methods work but I'm worried the mark scheme will focus on one.

Idk my revision guide supports what I wrote

ahh yeah my bad. just couldn't remember. Can't even remember what I wrote mainly. some of the stuff in that first post (of mine) were what I wrote, what you think?

that is incorrect as the answer is no longer balanced.

For the distillation question, do you reckon heating it all to over 100 and then cooling it in stages will get marks?
Both methods work but I'm worried the mark scheme will focus on one.

@ScienceFantatic The balancing is wrong; the irons don't balance.

the question already gave a little 2 next to the Fe so it isn't a big 4, for the first part of the equation

In pretty sure it was just sub atomic particles of boron and relative charges

yeah so its 2Fe2O3 + 3C -> 4Fe + 3CO2

Boron was the following question. The one I'm referring to asked you to refer to the structure of the nucleus.