2016 AQA GCSE Chemistry Unofficial mark scheme 2016

2Fe2O3+ 3C = 4Fe+ 3CO2( 2 marks)

I think the right answer is 2Fe2O3 + 3C = 2Fe2 + 3CO2

2Fe2O3+ 3C = 4Fe+ 3CO2( 2 marks)

I think the right answer is 2Fe2O3 + 3C = 2Fe2 + 3CO2

Wouldn't it be smelting instead of thermal decomposition?

What would the grade boundaries be like?

was it just in the nucleus for question 1?

was it just in the nucleus for question 1?

Nope, the metal carbonate is broken down by heating therefore thermal decomposition.

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can someone ****ing explain why its boron?

Yes.

Question 1
Electron shell: 2,3( 1 mark)
nucleus( 1 mark)
( +1), electrons( -1), neutron is uncharged( 3 marks)- not sure if it was in the nucleus or just the atom overall

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: the lower the metal on the reactivity series, the easier it is broken down(2)

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)

2Fe2O3+ 3C = 4Fe+ 3CO2( 2 marks)

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, reacted with hydrogen, 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)

Mark somewhere for completing drawing of the alkane(1)

Bromine goes colourless somewhere(1)

Took me a while to make so any rep would be much appreciated

Which question?

I missed the first question somehow and many others did too... HOW?!?!

It wasn't Boron it was Neon when explaining what was wrong with the structure. It had 9 electrons, Neon has 7

I said for the two conditions for cracking as:

mixed with steam
high temps

Would I get 2 marks?