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

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Specimen paper was really difficult and harder than the June 2013, since there's no grade boundaries I'd definitely say an A*.

Thankyou!

do you understand the second to last question? I cant seem to figure it out even with the mark scheme
also the 6 markers were really weirdly worded

Reply 2281

Krollo

Original post by Sulfur

Does anyone find some of this C7 really irrelevant? Such as the stages to introduce a new chemical process, how ethanol is produced and these quantitative analysis pages?

To be honest, every GCSE coursevis full of non sequitur topics, but the 7s are particularly bad. "Hey, everything seems logical so far... lol let's put a question about fizzy drinks in that has almost nothing to do with the specification"

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Reply 2282

Sulfur

Original post by Krollo

I can't tell you how much time I wasted by literally ranting in my mind thinking 'What the actual...' - and going through B7 in my head trying to spot a topic. Absolute crap OCR. It does make me laugh though, in reflection...

Reply 2283

Sulfur

Original post by Amyjonesx

Thankyou!

do you understand the second to last question? I cant seem to figure it out even with the mark scheme
also the 6 markers were really weirdly worded

I haven't finished C7 revision just yet and I don't understand it :frown:

The bond and gas chromatography six marker doesn't look bad, but that first one - what the hell? Reaction with a metal would work right? Meh.

Reply 2284

DDan123

Please help. I'm losing the motivation to revise for chem. And there's still P7 😭

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Reply 2285

totabatouta

Original post by DDan123

Please help. I'm losing the motivation to revise for chem. And there's still P7 😭

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Oh god tell me about it... C7 is soooooooooo longg.

Reply 2286

corporal

Who is up?? I'm starting revision at 9 am

Reply 2287

lyricalvibe

Original post by corporal

Who is up?? I'm starting revision at 9 am

I'm starting now! I've got district sports later so won't be able to revise for a massive chunk of the day -_-

How much you got left?

Reply 2288

ToLiveInADream

Is anyone onto past papers yet? I've finished notes and notes on the spec so I'm moving ooon..

Reply 2289

ToLiveInADream

Original post by DDan123

Please help. I'm losing the motivation to revise for chem. And there's still P7 ��

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Think about it this way. Next week you'll be FREE! So put the work in now and just relax later on :wink:

Reply 2290

corporal

Original post by lyricalvibe

I'm starting now! I've got district sports later so won't be able to revise for a massive chunk of the day -_-

How much you got left?

From the CGP bk- I'm starting Esters

Reply 2291

BarneyMartin

In paper chromatography; when the substances reach a dynamic equilibrium does this mean they stop moving up the paper?

Reply 2292

monisj1

Could someone explain dynamic equillibrium and chromatography please

Reply 2293

Amyjonesx

Original post by ToLiveInADream

Is anyone onto past papers yet? I've finished notes and notes on the spec so I'm moving ooon..

Ive already done both past papers and finished my notes so alls ive got left to do is read over notes which is the most boring part :frown:

Reply 2294

Pandorax

Does anyone understand the quantitative result section? Like it tells you this process of using an analytical method, then take a sample from the bulk, then dissolve or something, then there is this weird thing about product and proportionally? DX Can anyone explain? ;w;

Also please may someone tell me the equations we need to know?

Reply 2295

ToLiveInADream

Original post by Amyjonesx

Ive already done both past papers and finished my notes so alls ive got left to do is read over notes which is the most boring part :frown:

Haha, I never read over notes, just make them! I know I would fall asleep. Why don't you watch some videos?

https://www.youtube.com/results?search_query=ocr+21st+century+science+c7

Reply 2296

ToLiveInADream

Can someone explain equilibrium in chromatography to me please? It's mind-boggling. Is it talking about equilibrium in terms of the rates it moves up the stationary phase or..

Reply 2297

tigergirl8282

Original post by monisj1

Could someone explain dynamic equillibrium and chromatography please

Original post by BarneyMartin

In paper chromatography; when the substances reach a dynamic equilibrium does this mean they stop moving up the paper?

Original post by ToLiveInADream

Can someone explain equilibrium in chromatography to me please? It's mind-boggling. Is it talking about equilibrium in terms of the rates it moves up the stationary phase or..

In chromatography every chemical has its own dynamic equilibrium with the stationary and the mobile phase. If the position of equilibrium favours the stationary phase, the chemical will move slower, if the position of equilibrium favours the mobile phase it will move quicker. Basically the molecules in each chemical distribute themselves between the two phases and if there is more in the stationary phase then the equilibrium favours the stationary phase and the chemical move slower. The fact that each chemical has its own unique dynamic equilibrium means that each chemical moves at different rates, so they separate, and chemists can use this information to identify a chemical as the retention time/Rf value of a chemical is the same every time in the same conditions.

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Reply 2298

azo

Original post by ToLiveInADream

Can someone explain equilibrium in chromatography to me please? It's mind-boggling. Is it talking about equilibrium in terms of the rates it moves up the stationary phase or..

It's when the rate at which the amount of substance leaving the mobile phase into the stationary phase is equal to the amount leaving the stationary phase for the mobile phase :smile:

Reply 2299

azo

6 marker predictions anyone?