C7 OCR 21st Century Science Chemistry

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abbigm1
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#1
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#1
So the exam is tomorrow,
I cannot find the 2015 paper anywhere, if anyone has it can you please share it with me, really want to try the paper as it was 48 for an A*
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Rocco123
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I have the paper but have done it already, so my answers and scribbles are all over it. The six mark questions were:
The conversion of fats and oils into biodiesel needs a catalyst. The usual catalyst is hot concentrated sodium hydroxide. Scientists are investigating a new catalyst. The new catalyst is an enzyme. Evaluate both catalysts. Suggest which would be best and why.

Ben knows that chromatography depends on the attractions between the ink, the solvent and the paper. Explain why Spot 1 and Spot 2 end up in different places. (Spot 1 was higher up the TLC plate than Spot 2).

When chemical engineers design an industrial process, they make it as sustainable as possible. To make a process more sustainable, chemical engineers use renewable feedstock and reactions with high atom economy. Explain what the terms 'renewable' and 'atom economy' mean, and how each can make a process more sustainable.

The rest of the paper asked mainly about the Haber process, bond energies, carboxylic acids, making esters and fats and oils. Relative formula mass came up briefly too. Sorry I can't be of more help. Good luck tomorrow
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abbigm1
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#3
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(Original post by Rocco123)
I have the paper but have done it already, so my answers and scribbles are all over it. The six mark questions were:
The conversion of fats and oils into biodiesel needs a catalyst. The usual catalyst is hot concentrated sodium hydroxide. Scientists are investigating a new catalyst. The new catalyst is an enzyme. Evaluate both catalysts. Suggest which would be best and why.

Ben knows that chromatography depends on the attractions between the ink, the solvent and the paper. Explain why Spot 1 and Spot 2 end up in different places. (Spot 1 was higher up the TLC plate than Spot 2).

When chemical engineers design an industrial process, they make it as sustainable as possible. To make a process more sustainable, chemical engineers use renewable feedstock and reactions with high atom economy. Explain what the terms 'renewable' and 'atom economy' mean, and how each can make a process more sustainable.

The rest of the paper asked mainly about the Haber process, bond energies, carboxylic acids, making esters and fats and oils. Relative formula mass came up briefly too. Sorry I can't be of more help. Good luck tomorrow
Thanks so much, no wonder the grade boundaries were so high, all my favorite/easy topics came up
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KomradeKorbyn
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(Original post by Rocco123)
The conversion of fats and oils into biodiesel needs a catalyst. The usual catalyst is hot concentrated sodium hydroxide. Scientists are investigating a new catalyst. The new catalyst is an enzyme. Evaluate both catalysts. Suggest which would be best and why.
(Original post by abbigm1)
Thanks so much, no wonder the grade boundaries were so high, all my favorite/easy topics came up
What would/did you put for that first 6 marker, and did the actual paper give more information than that, or was that it?

All I can think of to write is stuff about how the sodium hydroxide catalyst requires a high temperature and so a lot of fuel is needed to provide the energy to heat it up, making it expensive, whereas the enzyme catalyst can work at a much lower temperature and so requires less energy and fuel therefore less money, making profit margins higher from the process when the enzyme is used as a catalyst.

Would that be enough for 6 marks? What else could I write if it's not enough?
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Rocco123
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The paper had a table with some more information, yes. You could say that enzymes can only catalyse one reaction so prevent side reactions from occurring, reducing waste and increasing atom economy. Also enzymes are fragile and need certain specific pHs and temperatures, so are not as well adapted for the industrial process. Enzymes are not yet widely used and so are expensive, more so than sodium hydroxide which is produced in bulk already.
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