AQA a couple of synoptic queries

Hey I'm revising chem and have a couple of quick queries. If anyone can help that would be brill.

module 5

1. Is scandium a transition metal or not?

-It's atom has a partially filled 3d sub level but it's ion Sc 3+ doesn't. In the text book it says "a transition metal must have a partially filled 3d sub level in atom or ion." But in revision guide it says the ion must be have the partially filled sub level.

module 2

2. I thought delta H= Q/moles but in text book it does delta H= (Q * Mr)/mass. Does anyone know which one is right?

Thanks!! :biggrin:

Reply 1

Pepe Le Poosh

Yeah I think Scandium is a transition metal because its atom has a partially filled 3d obrital. I usual count all 'd' block elements as transition metal, I don't know if i'm wrong or right to do that.

They're the same as Moles is mass/mr so Q/(mass/mr) is the same as (Q x Mr)/mass

Reply 2

poppy22

I know zinc isn't a transition metal because it always has a full 3d sub level and that's in the transition elements...

I don't know if I'm being stupid but isn't Q/ (mass/Mr) the same as (Q * mass)/ Mr -that's why I'm confused because in the book they've written it the other way up!?

Xx

Reply 3

Pepe Le Poosh

No, when dividing by fractions you slip the second fraction and times.

imagine it as...

(Q/1)/(mass/Mr)

this is rewritten as Q/1 x Mr/mass

Hence (Q x Mr)/Mass

Reply 4

poppy22