AS Chemistry- helping each other out!

Anyone writing up/written up their notes yet?

If so, are you up to date or where are you up to?

If not, when do you think that you will write up your notes?

I'm interested since quite a few people at my school haven't written up their notes yet and are just going from class notes for now.

Concentration shouldn't be what you're looking for when working out any enthalpies (including neutralisation)!! You should be looking for the moles which react. If two reactants have differing concentrations they might not have different moles if they have different volumes. All you need to do is work out how many moles reacted, meaning there may well be some left over reactant wondering where all of its friends went!

Firstly work out the moles of each reactant. Now work out what ratio they react in (usually 1:1 in the case of NaOH and HCl, but not things like H2SO4 and NaOH so be careful!). Assuming it's 1:1, choose the reactant with the smallest amount of moles. This is the moles which react, because once they're gone the reaction stops because there's nothing left for the other reactant to react with!

Yes, Sorry forgot to mention that I was using (number of moles = concentration x volume /1000) to work out the moles of the reactants, and hence I would have needed to use the concentration, also the volumes in a specific question are the same of both reactants and the example in the question is about H2SO4 and NaOH but Thank you as it has become slightly clearer!

Hey does anyone know why magnesium hydroxide is insoluble in water? thks

Anyone here doing the chemistry olympiad ?

Yep, tomorrow's the date I'm doing it

gl bro

I'm so worried I'm gonna flop

You doing it this year?

I'm sure you'll do fine you seem to know your stuff

Nah never got told about it or anything

The past papers look at things I haven't even covered and I'm like Stuff like IR (which I'm gonna cover later in the year)

Oh that sucks I'm sure there will be some things you can do

So long as I can gain a copper award or above, I'll be happy

Hey all. I am currently doing OCR A AS Chemistry and my teachers for it aren't great so I've been teaching myself a fair amount of the course.

Last year I got a high A* in Chemistry and I did this by memorising my notes and then trying past papers over and over to get used to applying the knowledge. Would this work for A-Level as well?

Also, any other advice for revision techniques that have worked quite well? Last year I didn't revise too much for my grade...whoops!

Thanks guys and have a good evening!

Good question and very difficult to answer...you probably don't have to know why for a-level. Just remember hydroxide solubility increases down the group and sulfate solubility increases up the group.

If you have the time (and concentration) then this might help:

http://www.chemguide.co.uk/inorganic/group2/problems.html