On 21 Feb 2005, at 17:55, Cynthia Singh wrote:

> Can anyone tell me how to make a 5M citric acid solution?  If I use
> 200 ml
> of DI water as the solvent, let's say, how many grams of the anhydrous
> citric acid solid do I need to make 5M?  And what is the formula to
> figure
> this out?

Anhydrous citric acid weighs 192.1 g/mol.
5 M means 5 moles of citric acid per 1000 ml.

  x mol    5 mol
------ = -------
200 ml   1000 ml

Therefore, in 200 ml, you'll want 1 mole of citric acid.

The mass of this is
1 mole citric acid x (192.1 g/mole) = 192.1 g.

Therefore, you'll want 192.1 g of citric acid.

Chris