OCR GCSE 21st Century Chemistry C1 C2 C3
Chemistry exam discussion - share revision tips in preparation for GCSE, A Level and other chemistry exams and discuss how they went afterwards.
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Re: OCR GCSE 21st Century Chemistry C1 C2 C3For me the B123 exam and C123 exam are exactly one month apart, so lots of revision time. We have done a lot in class. The B123 practice papers had only like 70%+ for an A* so if they are the same for the other exams then I should be able to get an A* easily, as on all the practice papers I've been getting A*s and dropping only like 3/4 marks. However the way UMS works means that this means nothing as far as I can see it.
The topics I am least certain on include:
Minerals in the Earth etc.
Atmospheric evolution
Polymers
The rest is just exam technique really. I don't think I need to do that much revision but I'm trying to do 1/2 an hour each day at least.
Practice questions for anyone who cares
1) Explain the different methods of obtaining salt and the uses that they are most suited to. (6)
2) Complete the following chemical equation:
Methane + Oxygen = __________ + _________
CH4 + 2O2 = __________ + _________
(3)
3) Match up the cause of an atmospheric change and the gas(es) it changed. Each cause and/or gas may have more than one line.
Volcanoes Nitrogen
Green plants Oxygen
Carbon Dioxide
(3)
4) State two ways that polymers can be changed and the properties that this affects.
Change 1 ________
Properties affected ________________________________ _____________________-
Change 2_________
Properties affected ________________________________ _____________________
(4)
5) When brine is electroysed, three products are formed. List them.
1___________
2___________
3___________
(3)
My answers (may be wrong)
1) Solution mining can be used to obtain salt. This entails pumping water into a salt deposit and then using the resultant brine as and when needed. It is suited to the chemical industry as the salt is relatively pure but has health risks attached to it. Salt mining can also be used to obtain salt. This entails using machinery to dig salt out of underground deposits. This is suited to use as rock salt or grit as the salt contains many impurities so cannot be used in the chemical or food industries. Finally, evaporating seawater can be used to obtain salt. This is suited to the food industry as the salt obtained is very pure.
2) = Water + Carbon dioxide
= 2H2O + CO2
3) Volcanoes -> Nitrogen, Carbon Dioxide
Plants -> Carbon Dioxide, Oxygen
4) Plasticization
It reduces forces between polymers, lowering their boiling point and making them more flexible.
Cross-linking
It chemicularly bonds polymer chains, increasing their boiling point, increasing forces between them and making them stronger.
5)Sodium Hydroxide
Hydrogen
Chlorine
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Thanks helped a lot(Original post by Krollo)
For me the B123 exam and C123 exam are exactly one month apart, so lots of revision time. We have done a lot in class. The B123 practice papers had only like 70%+ for an A* so if they are the same for the other exams then I should be able to get an A* easily, as on all the practice papers I've been getting A*s and dropping only like 3/4 marks. However the way UMS works means that this means nothing as far as I can see it.
The topics I am least certain on include:
Minerals in the Earth etc.
Atmospheric evolution
Polymers
The rest is just exam technique really. I don't think I need to do that much revision but I'm trying to do 1/2 an hour each day at least.
Practice questions for anyone who cares
1) Explain the different methods of obtaining salt and the uses that they are most suited to. (6)
2) Complete the following chemical equation:
Methane + Oxygen = __________ + _________
CH4 + 2O2 = __________ + _________
(3)
3) Match up the cause of an atmospheric change and the gas(es) it changed. Each cause and/or gas may have more than one line.
Volcanoes Nitrogen
Green plants Oxygen
Carbon Dioxide
(3)
4) State two ways that polymers can be changed and the properties that this affects.
Change 1 ________
Properties affected ________________________________ _____________________-
Change 2_________
Properties affected ________________________________ _____________________
(4)
5) When brine is electroysed, three products are formed. List them.
1___________
2___________
3___________
(3)
My answers (may be wrong)
1) Solution mining can be used to obtain salt. This entails pumping water into a salt deposit and then using the resultant brine as and when needed. It is suited to the chemical industry as the salt is relatively pure but has health risks attached to it. Salt mining can also be used to obtain salt. This entails using machinery to dig salt out of underground deposits. This is suited to use as rock salt or grit as the salt contains many impurities so cannot be used in the chemical or food industries. Finally, evaporating seawater can be used to obtain salt. This is suited to the food industry as the salt obtained is very pure.
2) = Water + Carbon dioxide
= 2H2O + CO2
3) Volcanoes -> Nitrogen, Carbon Dioxide
Plants -> Carbon Dioxide, Oxygen
4) Plasticization
It reduces forces between polymers, lowering their boiling point and making them more flexible.
Cross-linking
It chemicularly bonds polymer chains, increasing their boiling point, increasing forces between them and making them stronger.
5)Sodium Hydroxide
Hydrogen
Chlorine
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Re: OCR GCSE 21st Century Chemistry C1 C2 C3HARD!!!(Original post by alj123)
How did everyone find the exam?
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Re: OCR GCSE 21st Century Chemistry C1 C2 C3I didn't actually find it too difficult! Some of the questions about graphs and data were a bit weird and the polymer graph about strength and stretchiness was quite confusing. Oh, and we hadn't learnt about electrolysis cells, but I thought all the 6 mark questions were really easy!
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Re: OCR GCSE 21st Century Chemistry C1 C2 C3Hey guys, just need confirmation on a few questions:
> What was up with that table 2 calculation thing? I got 14 in the end but I know it's wrong, I couldn't figure it out!
> Also, did you guys tick the boxes for energy input for making the material and the other energy input one?
> The last thing I wasn't sure about was that number of molecules one.. I put 4 molecules in total (the conservation of atoms) but there wasn't 4 molecules, there were more?
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Re: OCR GCSE 21st Century Chemistry C1 C2 C3yer i didnt like that question either i hope ive done alright tho cus i thought it ws quite hard(Original post by kirstyjones <3)
I didn't actually find it too difficult! Some of the questions about graphs and data were a bit weird and the polymer graph about strength and stretchiness was quite confusing. Oh, and we hadn't learnt about electrolysis cells, but I thought all the 6 mark questions were really easy!
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Say whaaaat? I don't remember that :s(Original post by Aidn)
Hey guys, just need confirmation on a few questions:
> What was up with that table 2 calculation thing? I got 14 in the end but I know it's wrong, I couldn't figure it out!
> Also, did you guys tick the boxes for energy input for making the material and the other energy input one?
> The last thing I wasn't sure about was that number of molecules one.. I put 4 molecules in total (the conservation of atoms) but there wasn't 4 molecules, there were more?
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I found it quite hard. I don't know what to expect really.(Original post by rudegyal)
Am i the only person who found it hard? What do you think the grade boundaries will be? Hopefully they will be low.. -
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Re: OCR GCSE 21st Century Chemistry C1 C2 C3Yeah same! The grade boundries for core students in january was 64% for an A*!!! hopefully it'll be like that for us!(Original post by alj123)
I found it quite hard. I don't know what to expect really. -
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Yes, hopefully.(Original post by rudegyal)
Yeah same! The grade boundries for core students in january was 64% for an A*!!! hopefully it'll be like that for us!
If anyone has answers, please feel free to post them. -
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Re: OCR GCSE 21st Century Chemistry C1 C2 C3I found this exam alright, how did everyone do on the six mark questions? Did anyone notice that there was one 6 mark question for c1 and 2 6 mark questions for c2 but no 6 mark question for c3.. that's weird..normally you would have expect to see one 6 mark question per topic - hopefully everyone does well !! (:
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Re: OCR GCSE 21st Century Chemistry C1 C2 C3Yeah, just realised that you're all doing the new spec..(Original post by alj123)
Say whaaaat? I don't remember that :s
I was doing a retake of the old one ¬_¬
