# 3 M sodium acetate preparation - (Apr/25/2006 )

Hi all, i have a doubt, when you prepare 3 M sodium acetate in certain volume the sodium acetate increase the volume for example, if i need to prepare 100 ml of this solution, i need to add 40.83g of NaC2H302 and then when i add 50 the water, the volume increase almost twice , so.... is necesary to add the rest of the water ??????, what is the real concentration de sodium acetate in this 50 ml of water that i add?????

-MCR-

QUOTE (MCR @ Apr 25 2006, 02:49 PM)
Hi all, i have a doubt, when you prepare 3 M sodium acetate in certain volume the sodium acetate increase the volume for example, if i need to prepare 100 ml of this solution, i need to add 40.83g of NaC2H302 and then when i add 50 the water, the volume increase almost twice , so.... is necesary to add the rest of the water ??????, what is the real concentration de sodium acetate in this 50 ml of water that i add?????

The mw of sodiumacetat (without water) is 82,03 g/mol. For 100 ml of 3M solution you have to solve 3 * 82,03 * 0,1 = 24,609 g in a total volume of 100ml. Put the 24,609 g in a graduated cylinder, at some water for dissolving and than fill up for a total volume of 100ml!

For the concentration of your solution use
40,83 g / (82,03 g/mol * total volume in l of your solution), this is the concentration!!!

-ms-olli-

You just need to make it up to 100ml final volume rather than add 100ml to your solids

-John Buckels-

but when i add 50 ml odf water to the sodium acetate, in order to solubilize it, the solution volume is almost 100 ml so, i don't need to add the entire 50 ml of water left????

QUOTE (John Buckels @ Apr 26 2006, 04:54 AM)
You just need to make it up to 100ml final volume rather than add 100ml to your solids

-MCR-

No you don't. Just add the little bit extra required to make 100ml final vol

-John Buckels-

QUOTE (John Buckels @ Apr 26 2006, 01:08 PM)
No you don't. Just add the little bit extra required to make 100ml final vol

You donĀ“t have to add 100 or 50 ml. Just add enough water until a total volume of 100ml, composed out of the 24g salt and the rest water!

-ms-olli-

thank you so much!!!!, i did that but i was not complete sure about it.

QUOTE (John Buckels @ Apr 26 2006, 10:08 AM)
No you don't. Just add the little bit extra required to make 100ml final vol

-MCR-

Can this be autoclaved or do we need to filter sterilize?

-highlander-

u can autoclave

-T. reesei-

Strange - calculations done using concentration calculator show that you need about 87 mL of water to prepare such solution (exactly 86.74mL), much more than 50mL.

-Borek-