# GCSE OCR 21st Century Triple Science (CBP1-7) ThreadWatch

4 years ago
#2441
What's the C7 theory?
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#2442
(Original post by JasonBrown2K14)
You never know. You may walk into the exam hall at 2.00pm today and come out at 3.00 saying 'I owned that paper!' with a big grin on your face.

I am just having breakfast and then I'm cracking open the past papers. I went to bed yesterday murmuring all the C7 theory - I think I've revised too much! :P
I can only hope I need to nail this paper but I'm doubting it - I hate standard solution, it makes no sense and all of this on ethanol is a pain too! Good luck!
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4 years ago
#2443
(Original post by Sulfur)
I can only hope I need to nail this paper but I'm doubting it - I hate standard solution, it makes no sense and all of this on ethanol is a pain too! Good luck!
Thanks for the haber process
I fell asleep also can you please explain titration
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#2444
(Original post by eelg100)
Thanks for the haber process
I fell asleep also can you please explain titration
Titrations are used to find out how much volume of alkali is needed to neutralise the acid.

1. Use a burette and fill it with an alkali
2. Pipette the acid into the conical flask
3. Use a white tile and place it under the conical flask (to see colour change more vividly)
4. Add two drops of indicator - this shows the change in colour/neutralisation
5. Slowly, one drop at a time, add the alkali to the acid through the burette
6. When there's a colour change, you can work out the amount of alkali needed to neutralise the acid by the total volume - volume used = volume needed to neutralise (end point)
7. Use this as a rough titration, and do three more repeats and get them +- 0.2 cm3 between each other so that they're concordant.
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4 years ago
#2445
(Original post by Sulfur)
Titrations are used to find out how much volume of alkali is needed to neutralise the acid.

1. Use a burette and fill it with an alkali
2. Pipette the acid into the conical flask
3. Use a white tile and place it under the conical flask (to see colour change more vividly)
4. Add two drops of indicator - this shows the change in colour/neutralisation
5. Slowly, one drop at a time, add the alkali to the acid through the burette
6. When there's a colour change, you can work out the amount of alkali needed to neutralise the acid by the total volume - volume used = volume needed to neutralise (end point)
7. Use this as a rough titration, and do three more repeats and get them +- 0.2 cm3 between each other so that they're concordant.
I'm sorry for the constant questions but the cgp is full of detailed unnecessary info.You explain it much better
Also I'm only left with chromatography which my teacher said it is a possible 6 mark question.Can you please help me understand.It help me a lot.
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4 years ago
#2446
Can someone post a link fr the c7 specimen paper Markscheme Please
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4 years ago
#2447
I'm so nervous for this exam and I've been through content to an extent where I just don't want to do it anymore :'( what do you guys recommend ?

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4 years ago
#2448
When the molecule stops moving has it reached dynamic equilibrium because the amount leaving the mobile phase for the stationary phase is equal to the amount leaving the stationary phase for the mobile phase so the over all effect is nil I.e they stop

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4 years ago
#2449
Lol!! Haha that's a good one. Mine is Ron Dyed Potter's Deathnote

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Lol mine is Rape Dat Purple Dinosaur
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4 years ago
#2450
Can someone post a link fr the c7 specimen paper Markscheme Please
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4 years ago
#2451
(Original post by corporal)
Can someone post a link fr the c7 specimen paper Markscheme Please
C7 Specimen paper mark scheme is under the questions here:

http://www.ocr.org.uk/Images/80682-u...accredited.pdf
1
4 years ago
#2452
(Original post by corporal)
Can someone post a link fr the c7 specimen paper Markscheme Please
Voila.

And I have put the C7 June 2013s in.
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4 years ago
#2453
Guys, would anyone be able to tell me the answers to any of these questions in quick bullet points?;w;

>Describe the procedure of quantitative analysis using titration
>Discuss the sustainability and impact on the environment of the process used to manufacture ammonia and fertilisers

>Sustainability and environmental impacts/social impacts if any of biotechnology, synthesis and fermentation

>Explain what is meant by the term dynamic equilibrium, use the haver process as an example

Thankyou! You don't have to answer all of them, but if you know an answer to any of them please say 8-8)/)
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4 years ago
#2454
(Original post by Pandorax)
Guys, would anyone be able to tell me the answers to any of these questions in quick bullet points?;w;

>Describe the procedure of quantitative analysis using titration
>Discuss the sustainability and impact on the environment of the process used to manufacture ammonia and fertilisers

>Sustainability and environmental impacts/social impacts if any of biotechnology, synthesis and fermentation

>Explain what is meant by the term dynamic equilibrium, use the haver process as an example

Thankyou! You don't have to answer all of them, but if you know an answer to any of them please say 8-8)/)
Dynamic equilibrium is when the amount of products and reactants does not change. It occurs within reversible reactions, so both reactions are happening at the same rate. For example if someone enters a shop every time someone leaves, the concentration stays the same.
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4 years ago
#2455
On the first question on the specimen paper it asks "what is the functional group of carboxylic acids" and on the mark scheme it's COOH and not -COOH
Why??
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4 years ago
#2456
Methanoic acid is a weak acid and hydrochloric acid is a strong acid.
Describe a reaction, other than with carbonates, that shows that methanoic acid is an
acid.
Compare this with a similar reaction of hydrochloric acid to demonstrate why one is a
weak acid and the other a strong acid.
 The quality of written communication will be assessed in your answer to this question

Someone help me out on this, I just really don't understand it :/ thanks
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4 years ago
#2457
(Original post by -sophia-)
On the first question on the specimen paper it asks "what is the functional group of carboxylic acids" and on the mark scheme it's COOH and not -COOH
Why??
It's the same thing

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4 years ago
#2458
(Original post by Swag>education)
It's the same thing

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Ahh ok thanks I was really confused!
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4 years ago
#2459
Can anyone describe fractional distillation in note form please?
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4 years ago
#2460
(Original post by -sophia-)
Can anyone describe fractional distillation in note form please?
- Put your alcohol under a fractionating column, and heat it gently.
- The top of the column is at the precise temperature so that only alcohol gets there without condensing.
- The alcohol fumes flow through a condenser, which reforms them into a more concentrated alcohol.

Repeat, if you want.

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