> > From: Bob Shell <[EMAIL PROTECTED]> > Date: 2007/02/10 Sat PM 08:47:45 GMT > To: Pentax-Discuss Mail List <[email protected]> > Subject: Re: Obscure unit conversions > > > On Feb 10, 2007, at 2:53 PM, David Weiss wrote: > > > The word "mole" refers to a number of particles, it is not a > > concentration unit. Molarity is a concentration unit, equal to > > moles of > > solute per liter of solution. If you have a solution of 0.100M NaOH, > > that is 0.100 moles of NaOH per liter of solution, that is 4.00 > > grams of > > NaOH in a liter of solution. Molality is used quite a bit too. > > > OK. How did you get from 0.100 moles per liter to 4.00 grams per > liter? That's the part I'm not getting.
The Molecular Mass of NaOH is 40. So 40g in one litre would be 1molar. 0.1 molar is therefore 4g per litre. It's all based on the way chemicals react. 1litre of NaOH solution will react completely with 1litre of HCl solution, at the same molarity. If you have a known strength solution, you can react it with an unknown and work out, from how much you need, how much chemical is in the unknown. Equally, you can work out in advance how much solution you need to react with waht you already have. ----------------------------------------- Email sent from www.virginmedia.com/email Virus-checked using McAfee(R) Software and scanned for spam -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
