h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I'm stuck gang. I can't remember how to calculate the portions of NaOH to H2O to make a 10% dilute solution. Can anyone help?

A 10% solution would be 10g of NaOH dissolved in water to a *final volume* of 100 mL (ie, not simply dissolved in 100mL of water)

how did you come to those numbers?

Because the definition of an X% solution is Xg of solid dissolved and made up to 100mL - it doesn't matter what the solid is!

ooooooohhhhh, here i was trying to mess with a molecular formula and all that jazz. Ha! thanx a million friend!

Nah - you only need those if you're trying to make up a solution to a particular molarity (e.g. a 0.1M solution of NaOH)

I am constantly amazed that on h2g2 there is always someone who seems to be able to come up with an answer however technical or obscure, a reply came within minutes to this one!

I see I'm arriving very late to this one. So I'll just point out that there are *lots* of different definitions and calculations of concentration/dilution. I found that someone has made a collection on wikipedia which might be useful for future reference:

http://en.wikipedia.org/wiki/Concentration

I had a feeling that there would be someone in here who knew this kind of thing. that's why i skipped google, ask, all the search engines, really.