GCSE OCR 21st Century B7 C7 P7 - W/C - Monday 20th June 2016

Okay so what is it that you struggle with for titrations? I can remember finding the equations difficult because I didn't understand the units, or what was going on.

Don't worry about the moles bit.

Yeah the units and equations, as well as the process generally.

This will be hard to explain over TSR. The CGP guide might be good, I don't know,

@richpanda Do you have any tips to revise and do well in this exam?

How I revised for C7 was by writing out subheadings for the different sub-topics, such as esters, weak/strong acids, green chemistry, and then wrote notes for each part, and did past papers.

C7 is seriously difficult, don't get too upset if you're only getting 40/60 or whatever. The specimen paper for C7 is as hard if not harder than plenty of the things you would do in AS chemistry.

That's a relief I was wondering how hard chemistry would get next year!

It's got more maths in it, which is good. Just more interesting stuff in general.

Please can you help me with C7? I'm (hopefully) doing chemistry for a level but I'm so stressed for this, I feel as if I know nothing at all

If I start proper revising for the 7s tomorrow is that enough time?

Yes it's more than enough time. You're going to have to be specific in what you want me to help you with.

Thank you, I struggle most with remembering reactions of alcohols with sodium and air, ways to produce alcohol and the disadvantages and advantages of those methods and methods for preparing esters.

C7 and B7 is okay but I find P7 the hardests epecially the pressure/temperature etc. equations. Any tips would be appreciated

Pos
ted from TSR Mobile

The pressure, temperature and volume equations are given in the exam paper. You know the constant is whatever isn't in the equation, e.g pressure/temperature=constant, therefore the constant must be the volume. You can then write it as P1/T1=P2/T2. This makes it easier to work out the pressure or volume as you can rearrange it.

Just a quick one. Ethanol (which is an alcohol) can be made by fermentation or biomass. The fermentation method is more harmful for the environment as it produces carbon dioxide whereas the biomass method doesn't produce anything harmful. Hydrogen can be recycled into the Haber process and then in the next stage Ethanol is produced. However for this method, the raw materials, such as crude oil and natural gas will eventually run out. The fermentation process won't run out of raw materials because the sugar beet and yeast used for it grow quickly. Just a quickie but the CGP revision guide is good to revise from.

Thanks and I know but my parents won't get me them

I don't know how this will work but I could try and give you my account details for the CGP online edition. It probably won't like it but its worth a try?