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OCR Gateway B Chemistry June 2014 - C1-C6

Rather than making two threads, I thought I'd just make the one for both of the exams.

Exam information:

C1, C2 and C3 - 6th June (PM)

C4, C5 and C6 + data analysis - 16th June (AM)

I got these all wrong for biology, but I think I might get them right now - my predictions for the six mark questions:

C1 - Smells - something to do with perfumes, maybe esters or their volatility

C2 - Haber process - state the equation and explain the conditions

C3 - Exothermic and endothermic reactions OR allotropes of carbon/nanotechnology

C4 - explaining one of the types of bonding (maybe metallic) or comparing them, though it could simply be purifying and testing water.

C5 - strong and weak acids: give the equations and then explain the differences

C6 - depletion of the ozone layer (give the equations) and explain the consequences of this

I think displacement comes up for C4, C5 and C6, so I would definitely recommended revising that, as it might feature as part of a 6 mark question.

These are likely to be wrong, but it's just a suggestion, eh?

I'll post resources on here soon :smile:

How is everyone getting in with their revision, by the way?



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(edited 9 years ago)

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Hopefully this exam will go well, like biology
Reply 2
Original post by Pikki1234
Hopefully this exam will go well, like biology


Hopefully, how are you revising?


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Original post by kingaaran
Hopefully, how are you revising?


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Just trying to do as many past papers. What about you?
Reply 4
Original post by Pikki1234
Just trying to do as many past papers. What about you?


Same, and I'm making sure I know all aspects of the specification. :smile:


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How is revision, guys? The grade boundaries are quite low for science so we should be fine anyway (:
Original post by kingaaran

....I'll post resources on here soon :smile:

How is everyone getting in with their revision, by the way?



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Are there any resources you can provide?
Thanks
Someone please help with harber process, electrolysis of brine and normal electrolysis, esters


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Chemistry have the highest grade boundaries of all science topics. So its best not to rely on low grade boundaries. Anyway, an A* is 360/400 UMS. It means that you have to basically get A* in both papers, unless you get a high A* in CA, which gives you some opportunity to get an A in one exam and still get an A* overall.
:rolleyes:
Reply 9
Original post by lowhigh
Are there any resources you can provide?
Thanks


What would you like, as I can then try to find it? I have 6 mark questions for every topic in C1, C2 and C3, which I have attached. I have marked exemplar answers to them, if you would like them too?
Original post by kandykissesxox
Someone please help with harber process, electrolysis of brine and normal electrolysis, esters


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Haber process

This is used to manufacture ammonia. It uses nitrogen and hydrogen to do this. This is easy to remember, as the molecular formula for ammonia is NH3, so you can see that there is nitrogen and hydrogen going in there. In the Haber process, all that happens is that you take the nitrogen and hydrogen and react them together:

Nitrogen + Hydrogen <--> Ammonia
N2 + 3H2 <-->2NH3


However, you can't just put them together and expect to get ammonia instantly, as the particles will take awhile to react, so we add some conditions to speed this up, increase the yield (how much is produced) and lower the building costs: iron catalyst, high pressure, temperature of 450 degrees and a recycling tube, where unreacted nitrogen and hydrogen are recycled.

All you need to know now is why these conditions are used:

A high pressure is used to increase the percentage yield of ammonia, but it's not too high, as that will mean that the building costs will be high and there could be the chance of an explosion.

A high temperature is used to increase the rate of reaction, but it's not too high otherwise the yield would be too low, as the reaction will start to go backwards, as it's reversible - you don't really need to know the last bit, but it's good to know anyways, as you'll need it for C5.

A catalyst is used to increase the rate of reaction without changing the yield. It doesn't change the yield, as it doesn't take part in the reaction itself.

If you're wondering why unreacted nitrogen and hydrogen is recycled, well, think to yourself, if they weren't recycled, what would happen to them? Nothing! They'd be wasted. Hence, by recycling them, the amount of waste products produced is reduced, increasing the efficiency of the reaction.

Another bit of detail that you need to know is why is ammonia important for the world food production: all of the crops that are grown in the world require nitrogen and most of this comes from artificial fertilisers. But guess what? The first step of making most of these fertilisers is the Haber process, which is why the production of ammonia is so important.

I'll do the rest of the topics in a bit :biggrin:
Original post by kandykissesxox
Someone please help with harber process, electrolysis of brine and normal electrolysis, esters


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Electrolysis of brine can be complicated and I only started to understand electrolysis after having done it in C6 :redface:

Read on here



This one is about esters

Read more about esters



Hope it helps!
Reply 12
I'm in this!

The test tomorrow shouldn't be bad, just need to go over a few topics to refresh memory. C4C5C6 could be a monster though
Original post by kingaaran
Haber process

This is used to manufacture ammonia. It uses nitrogen and hydrogen to do this. This is easy to remember, as the molecular formula for ammonia is NH3, so you can see that there is nitrogen and hydrogen going in there. In the Haber process, all that happens is that you take the nitrogen and hydrogen and react them together:

Nitrogen + Hydrogen <--> Ammonia
N2 + 3H2 <-->2NH3


However, you can't just put them together and expect to get ammonia instantly, as the particles will take awhile to react, so we add some conditions to speed this up, increase the yield (how much is produced) and lower the building costs: iron catalyst, high pressure, temperature of 450 degrees and a recycling tube, where unreacted nitrogen and hydrogen are recycled.

All you need to know now is why these conditions are used:

A high pressure is used to increase the percentage yield of ammonia, but it's not too high, as that will mean that the building costs will be high and there could be the chance of an explosion.

A high temperature is used to increase the rate of reaction, but it's not too high otherwise the yield would be too low, as the reaction will start to go backwards, as it's reversible - you don't really need to know the last bit, but it's good to know anyways, as you'll need it for C5.

A catalyst is used to increase the rate of reaction without changing the yield. It doesn't change the yield, as it doesn't take part in the reaction itself.

If you're wondering why unreacted nitrogen and hydrogen is recycled, well, think to yourself, if they weren't recycled, what would happen to them? Nothing! They'd be wasted. Hence, by recycling them, the amount of waste products produced is reduced, increasing the efficiency of the reaction.

Another bit of detail that you need to know is why is ammonia important for the world food production: all of the crops that are grown in the world require nitrogen and most of this comes from artificial fertilisers. But guess what? The first step of making most of these fertilisers is the Haber process, which is why the production of ammonia is so important.

I'll do the rest of the topics in a bit :biggrin:



thanks for the help i was just wondering can i have some help on esters, polymers, alkanes and alkenes, electrolysis and bucky balls please
Original post by kandykissesxox
thanks for the help i was just wondering can i have some help on esters, polymers, alkanes and alkenes, electrolysis and bucky balls please


I posted above


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Original post by kingaaran


Do you want to skype later to revise?
Original post by kingaaran
What would you like, as I can then try to find it? I have 6 mark questions for every topic in C1, C2 and C3, which I have attached. I have marked exemplar answers to them, if you would like them too?


This is very helpful thanks. The exemplar answers would be nice too. :biggrin:
(edited 9 years ago)
Original post by kingaaran



hi can i have all of the 6 markers you have for c1-3 with answers please?
Original post by kingaaran

C1 - Smells - something to do with perfumes, maybe esters or their volatility

C2 - Haber process - state the equation and explain the conditions

C3 - Exothermic and endothermic reactions OR allotropes of carbon/nanotechnology



Esters came up on the January 2013 exam paper so i doubt it'll appear again..
(edited 9 years ago)
I think a six mark could be about the evolution of the atmosphere...hate that

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