Badges: 9
Report Thread starter 3 years ago
Just took the C1 exam for AQA and I think it went pretty well.

However I'm unsure about a couple of questions - for the final question on hydrogenation which was "What happens when you react vegetable oil with hydrogen in the presence of a nickel catalyst at 60C"

I put that 'it get harder because the hydrogen reacts with the double bond in the unsaturated fat and opens it up' will I get the 3 marks for it?

Also the question about what happens to the alkane molecules in this experiment (the one about burning paraffin). I put that 'The alkane molecules break down or split apart or crack on the surface or specks of the catalyst forming an alkane and an alkene. This is a form of thermal decomposition'. Again will I get the 3 marks for this?

These 2 questions are really irritating and stressing me out as I feel they'll be the difference between me getting an A or A*.

Thanks in advance
Badges: 3
Report 3 years ago
We don't know what the mark scheme is going to be like but your answers aren't very clear. The Hydrogen doesn't react with the double bond itself. The double bond is replace by the single bond and the Hydrogen bonds with the Carbon atoms. I think you also get a mark for saying the word hydrogenation.

For the second one, they wanted to proabably hear (catalytic) cracking, rather than "crack on the surface" which is interesting considering the alkane is a liquid. Thermanl decomposition is right. and alkane and alkene is right, but you may negate some marking points for saying some wrong things like "the catalyst forming..."

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