[harry1996]

Hi, I just started Chemistry at school this year and I'm really interested in it but you're going to think I'm a retard because I want you to explain some really basic stuff. I don't understand moles and how to work them out etc. and I don't know what a dm³ is or how to use it and blah. Any help would be appreciated,Harry.

[Borek]

dm³ is just a volume unit, identical to liter. That was not always the case, for historical reasons 40 yeras ago there was a minute difference between both, but they were unified somewhere in sixties.

Moles - have you read your book? Then google them, plenty of good stuff on the web.

And please read forum rules.

[harry1996]

k thats cool thanks. I was wondering, who decides what the amount in a particular unit is because you can't just change a certain measurement and call it something else because it wouldn't be accurate.

[Arkcon]

If you gave us an example, and showed us what you'd been able to figure out so far, we might be able to offer hints.  It sounds to me like you're at what I call Stage I -- converting from one unit to another.  This is where chemistry education tends to start.