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OCR Gateway Chemistry 24th May 2012 C1 C2 C3

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No, it was paraffin because per unit which I said could be 0.6g it released 2.5x more energy than ethanol and petrol... So unless it was 2.5x more expensive it is the most sensible choice. :smile:

Yah i put paraffin too because it is also not that flammable compared to petrol and ethanol. whatever they were. :biggrin:

Reply 21

bobbricks

Original post by MangoFreak

Paraffin had the greatest ratio between temperature change and mass combusted, meaning it released the most energy :smile:

What do you mean by greatest ratio? :smile:

Reply 22

milworthy

Is this the exam where the first question about the boiling point of LPG, and there was in C3 the first question was the amount of electrons in the outer shell of bromine?

Reply 23

bossun

Original post by milworthy

Is this the exam where the first question about the boiling point of LPG, and there was in C3 the first question was the amount of electrons in the outer shell of bromine?

I don't think this is the right paper. We never had that question. First question was about alkanes and alkenes and C3 was a graph question or something like that i believe :s-smilie:

Reply 24

bobbricks

Original post by milworthy

Is this the exam where the first question about the boiling point of LPG, and there was in C3 the first question was the amount of electrons in the outer shell of bromine?

No.

This is a different exam to yours- are you on the old syllabus (from 2006) or the new syllabus (from 2011). This exam paper is from the new syllabus

Reply 25

milworthy

Original post by bossun

I don't think this is the right paper. We never had that question. First question was about alkanes and alkenes and C3 was a graph question or something like that i believe :s-smilie:

Ok, i was really worried that I had completely missed out papers. Is this the new specc paper.

Reply 26

MangoFreak

Original post by bobbricks

What do you mean by greatest ratio? :smile:

Paraffin increased the temperature of the water by 25 degrees if I recall, while only burning 0.6g, whereas one of the other fuels only increased the temperature by 20 degrees, burning 1.2g. The other fuel was definately worse than that, I don't remember it specifically.

So the Paraffin increased the temperature of the water by 1 degree for every 0.024g of it, while the second fuel did the same for every 0.06g. I should have said smallest ratio, but basically the paraffin released more energy from a smaller amount.

Reply 27

milworthy

yes thank goodness i did the old spec!!! Do you think there is a thread for the old specc.

Reply 28

MangoFreak

Original post by milworthy

Is this the exam where the first question about the boiling point of LPG, and there was in C3 the first question was the amount of electrons in the outer shell of bromine?

I think electron shells are in C4 now, if they were ever in C3.

Reply 29

bobbricks

Original post by MangoFreak

Oh okay, thanks. Sigh. I got that question wrong :frown:

- how many marks did I lose for that question?

Reply 30

L'Evil Fish

Per 0.6g because they were all multiples of it.. 1.2 and 1.8

Reply 31

bobbricks

Original post by milworthy

yes thank goodness i did the old spec!!! Do you think there is a thread for the old specc.

I don't think so- I think you should create one! Remember to write Old Specification in the title so people don't get confused between this thread and your thread... :wink:

Reply 32

MangoFreak

Original post by shadab786ahmed

Per 0.6g because they were all multiples of it.. 1.2 and 1.8

Hmm?

Reply 33

MangoFreak

Original post by bobbricks

Oh okay, thanks. Sigh. I got that question wrong :frown:

- how many marks did I lose for that question?

Well, you might have justified your answer in a way that got you a couple of marks. If you said that ethanol released more energy then yeah you probably lost marks. It was probably a 2 or 3 mark question. Definately, actually, I just have no idea which :ahee:

Reply 34

L'Evil Fish

Only 2, but it could make the difference... BUT I'm sure it'll be fine! :awesome:

Reply 35

L'Evil Fish

Original post by MangoFreak

Hmm?

They said
Paraffin was 0.6g and change was 25
Ethanol was 1.8g and change was 30
Petrol was 1.2g and change was 20

So per unit of 0.6g
Paraffin is 25
Ethanol is 10
Petrol is 10

Reply 36

MangoFreak

Original post by shadab786ahmed

They said
Paraffin was 0.6g and change was 25
Ethanol was 1.8g and change was 30
Petrol was 1.2g and change was 20

So per unit of 0.6g
Paraffin is 25
Ethanol is 10
Petrol is 10

Ah right.

Reply 37

gcseis

Original post by bobbricks

How was it? Does anyone have an unofficial mark scheme?

For the thread on the OCR Gateway Biology 21st May exam--> http://www.thestudentroom.co.uk/showthread.php?t=2006071

I REALLY WANT THE UNOFFICIAL MARK SCHEME :mad:

Reply 38

gcseis

Can someone possibly send me a like to the unofficial mark scheme for higher tire c1 c2 c3 fot the thursday 24th of may exam! Stressing out! what did you guys write for the six mark (whay has the rates of nitrates of oxides decreased) question o_O

Reply 39

bobbricks

Original post by gcseis

The question was all to do with catalytic converters, which change carbon monoxide/ oxides of nitrogen into carbon monoxide/ carbon dioxide.

CO is poisonous (since it binds with hameoglobin etc.); oxides of nitrogen causes photochemical smog and acid rain; sulphur dioxide causes acid rain.