Could someone please tell me what the letters in w/v stand for? Any help would be appreciated.

In what context do you mean?

I'm sorry, I didn't make that clear at all. I am speaking in terms of solutions. e.g. a 0.4% (w/v) solution. I'm sorry if this still isn't clear.

percentage weight for volume - %w/v

This means the percent by weight of solute in the total volume of solution. Normally used where the solute is a solid. For example, a 10% w/v sodium fluoride solution would be prepared by dissolving 10 grams of sodium fluoride in 100ml of water.

Thankyou very much, that helps a lot.

Your welcome