I do not understand you really, are you sure you got the task correct? Because as I see it it says that you need 5ml of a 1M tris solution to get a 50mM solution in total (in 100ml)

ex: 8ml of a 5M NaCl sulotion is in 100ml ===> 8/100 * 5 = 0.4M

You have for each 100ml 5ml of a 1M tris solution to get a 50mM solution in total.

If you now need a 1M solution in total then you need..... ml of a 1M solution...?

ex. if you need 0.25ml of a 1M tris bottle to get a 0.1M solution in total, how much of this bottle do you need to use to get a 0.2M solution in total?

its simply x2 .... (keep in mind you need to take in this factor for the other substances to

thank.. i'm forget something

1 M tris , 5 M Nacl, 0.5 M EDTA and 10% sds is a Stock solution , so i need 50mM tris from 1 M €Tris stock solutions,

in 1 M Tris i should take 5ml of 1 M Tris to make 50mM, in TOTAL VOLUME 100ml

yes u are right..

thank for explanation

**Edited by zack, 26 June 2009 - 11:19 AM.**