Year 12s: what will be the first way you research your future options? >>

Rearranging chemistry formulae??

Yes, I know this should be really simple, but in fact it's the thing I get most stuck on in A2 chem. :s-smilie:

So yeah, what are the principles to apply?! I just can't remember - haven't done maths in 2 years!

So lets take a Kc equation as an example: Kc=[NO]^2/[N2]x[O2]. How would you rearrange this so that each value (don't know if that's the right word!) lies on the left?

Cheers :smile:

Reply 1

JamieEclipse

Which values? You need to be more clear :\
Either way just remember, what you do to one side, you do to the other.

Reply 2

TheProcrastinator

Original post by JamieEclipse

Which values? You need to be more clear :\
Either way just remember, what you do to one side, you do to the other.

Maybe they're called variables, I'm not sure! Well Kc is one, [N2] another and so on.

You say 'what you do to one side you do to another', but can you give an example?

Reply 3

JamieEclipse

For instance, if you wanted to move [O2] over.
To get rid of it on the right, you'd multiply by [O2].
Therefore you'd do it to the other side.
Making:
Kc[O2]=[NO]^2/[N2]

Same goes for divide, plus and minus.
Hope this helps.

Reply 4

TheProcrastinator

Original post by JamieEclipse

Ok, but what if I now wanted to move Kc over to the other side? Would it go below [NO]^2 next to [N2]?

Reply 5

Zygroth

Original post by TheProcrastinator

Ok, but what if I now wanted to move Kc over to the other side? Would it go below [NO]^2 next to [N2]?

Yes, because to get rid of it on the left, you divide by Kc so you must do the same thing to the right hand side, and divisions go on the bottom of a fraction.