Question

What do these symbols mean?

I've searched on the web for some of these symbols but I don't know what they mean:

1) `mol^-1`
2) `dm^-3`

I usually see `mol^-1` represent "something per mole", but I am not 100% sure of this. If someone could confirm with me, that would be greatly appreciated.

Also, for `dm^-3` , I usually see this unit pop up for concentration questions. My question is, how do I say it? For example, if I am reading a presentation to my classmates, how would I say the concentration of this compound is 1 mol `dm^-3` ? If someone could also clarify this issue with me, I'd be greatly thankful.

Lastly, just out of curiosity are there any other abbreviations that I should be concerned about, for example, `unit^-2`, `unit^-4`, etc?

Thanks.

Answer 1

You are correct, `mol^(-1) = 1/(mol)` or "per mole".

`dm` is a decimetre which is a unit of length. Cubing it gives a volume so `dm^(-3) = 1/((dm)^3)` which is "per volume". You would say "moles per cubic decimetre". Incidentally, a cubic decimetre is the exact same volume as a litre, giving the unit for concentration as `moll^(-1)` ("moles per unit litre") which rolls of the tongue a little bit nicer.