UNOFFICIAL MARKSCHEME ocr chemistry gateway today

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ellamoon_22
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C1

1) the one with a double bond and only carbon and nitrogen atoms i think it was E cant remember(1 mark)
b) C and F (C4 H10)(1mark)
c) C8 H18(1mark)
d)two brackets, n out side, no double bond displayed formula(1mark)

2)esterd have an oxygen atom(1mark)
b) i guessed 177 degrees idk(1mark)
c) not suitable solvent it cant evaporate (2 marks)

Guessed and said pie chart and line graph(2marks)

3)incomplete would be CH4 + O2 ----> C + 2H2O(2 marks)

4) Carbon cycle

- CO2 doesnt change much cause its recycled in the carbom cycle so even though plants take it in when they did etc it is released
-burning fossil fuels releases it back
-population increase will have negative effect and inceease the pollutants
-more cars so more carbon dioxide myb and nitrogen
-deforestation for land to grow crops
-ozond layer destroyed green house effect
-more burning of fossil fuels
-more use of aerosols
-more acid rain?? (6 marks)

5)Gortex has a membrane with small holes that allows water vapour to escape but too small to let water in. It allows perspiration(2 marks)

b)Gortex is more comfortable(1 mark)

6) oil based paint dries because solvent evaporatesm oil binding medium oxidies to forn hard film/layer(2 marks)
b) in colloid pigment is dispered throughouy mixture but pigmentt/solid particles are too small to dissolve
/seperate.??(2 marks)

Total 25 marks

C2

1)same fossils from continents found there is more evidence to support wegner. It has been tested?(2 marks)
2)oxidation means electrons lost(22mark)
3)amalgam-mercury, brass-copper and zinc, solder -lead and tin (3marks?)
4)aluminium is A because it doesnt rust in damp air.(2marks)
5) iron + oxygen + water----> hydrated iron oxide(2 marks)
6) harber (6 mark)
-350 and 450 i think
They dont use low temp cause slows rate of reaction ammonia made slower
-dont use high presure cause expensive
-They use comprimise temp and pressure

7) potassium nitrate and water (salt and water)(2marks)
8)fertilisers have to be soluble so they can be taken up by roots(1mark)
9)eutrophication (3marks)
-fertilser increase growth of algae
-algae blocks light ..planrs die
-aerobic bacteria feed on dead organisms
-use oxygen up
-aquatic animals larger ones die

Total 23/25 marks- two questions missing or marks wrong

C3

1)?energy i got it wrong (8000j)
B) temp change got it wrong (10 degrees)
2)concentration means crowded increase frequency of collision
3)168---->other numbers add up to 168
4)?
5) rearrange percentage yield equation and it proves it
6)bond making is exothermic bond breaking is endothermic. It is exo because heat given out instead of taken in (3 marks)
7) batch is labour intensive and raw materials used to make drugs is hard get. People tjink unethical and testing banned in some countries (3 marks)

8) chromotography (6marks)

-crush plant
-dissolve with a solvent/ boil
-chromotography w/concentrated solution
-not pure not fixed boiling point
-2 dots

the rate of reaction was 1.5- 1.47
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rose.i
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I got E for the first question and F and C for the second one. And then C18 H8 for the third one I thinkk
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AA11AAA
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what do you think the grade bounderies are like
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ellamoon_22
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(Original post by rose.i)
I got E for the first question and F and C for the second one. And then C18 H8 for the third one I thinkk
I cant remember the letters but i got for theh second one C8 H18
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Gamer_44
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If the perfume had a high boiling point, then surely it would be harder to evaporate as more energy is required taking more time?
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robyn2000
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(Original post by Gamer_44)
If the perfume had a high boiling point, then surely it would be harder to evaporate as more energy is required taking more time?
I put that larger molecules dont evaporate as easily, stronger intermolecular forces? But not too sure
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ellamoon_22
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(Original post by Gamer_44)
If the perfume had a high boiling point, then surely it would be harder to evaporate as more energy is required taking more time?
Ur right. I guessed my answer i wanted to put that the large molecules have strong forces etc so dont evaporate but i thought i shouldnt write that cause thats for crude oil in the fractioning column my bad
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Gamer_44
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(Original post by robyn2000)
I put that larger molecules dont evaporate as easily, stronger intermolecular forces? But not too sure
Yes, but because it was a data analysis question you may not require the second part but good anyway!

The boiling point was going up in 25's or something?
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ellamoon_22
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(Original post by Gamer_44)
Yes, but because it was a data analysis question you may not require the second part but good anyway!

The boiling point was going up in 25's or something?
They may allow a range of 150-70
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mxskaan
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I swear there wasn't an atom economy question?

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brainzistheword
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wasnt the 6 marker in C3 about chromatography?
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ellamoon_22
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(Original post by brainzistheword)
wasnt the 6 marker in C3 about chromatography?
Yhh
And how drugs extracted from leaves
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brainzistheword
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(Original post by ellamoon_22)
Yhh
And how drugs extracted from leaves
Ah cool - and for the energy transferred thingy - was it 8000 or 32000?
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ellamoon_22
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(Original post by brainzistheword)
Ah cool - and for the energy transferred thingy - was it 8000 or 32000?
Personally got 8000j

it is energy supplied /fuel burnt
?/2.0g

Now that I think bout it u might have to rearrange the equation (where they asking for energy supplies?)

the one I used was to find energy per gram.
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brainzistheword
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(Original post by ellamoon_22)
Personally got 8000j

it is energy supplied /fuel burnt
?/2.0g

Now that I think bout it u might have to rearrange the equation (where they asking for energy supplies?)

the one I used was to find energy per gram.
It said the fuel supplied 16000J/g how much is supplied if 2.0g burned

I think
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ellamoon_22
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I'm not sure what they asked for if they asked for energy supplies it would be 32000 if they asked energy per gram it would be 8000
(Original post by brainzistheword)
It said the fuel supplied 16000J/g how much is supplied if 2.0g burned

I think
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brainzistheword
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(Original post by mxskaan)
I swear there wasn't an atom economy question?

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I think there might have been
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ellamoon_22
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(Original post by brainzistheword)
I think there might have been
Same
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Wolfram Alpha
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There was not. There was only one percentage yield question.
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mxskaan
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(Original post by Wolfram Alpha)
There was not. There was only one percentage yield question.
thank you i think people are getting confused with that question that asked to show conservation of mass is 168?
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