## Dilution question

Discussion of all aspects of biological molecules, biochemical processes and laboratory procedures in the field.

flatrpo
Garter
Posts: 1
Joined: Wed May 12, 2010 10:42 am

### Dilution question

Hey,

I have a solution of 18 wt % (about 1g/ml) I want to make it into a solution of 2 wt % by diluting it with water. Using C1 V1 = C2 V2 could someone show me how to do it. I have tried but seem to be getting muddled somewhere.

Thanks!

JackBean
Inland Taipan
Posts: 5694
Joined: Mon Sep 14, 2009 7:12 pm
what you used is for concentration on mol/dm3, not for wt %.

You have to use w1*m1 = w2*m2
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

clevermizo
Garter
Posts: 7
Joined: Thu Jan 28, 2010 3:48 pm

### Re: Dilution question

The units are arbitrary at this point and don't affect the calculation, since the starting units and the ending units are the same.

If I have a solution of 18 fiddledeecups and I want to dilute it down to 2 fiddledeecups, well that's a dilution factor of 18/2 = 9.

So, if I want 9 mL, I use 1 mL of 18 fiddledeecups and add 8 mL of diluent (water in this case). Since the dilution factor is 9, make your final volume a multiple of 9 to make your calculations easier.

JackBean
Inland Taipan
Posts: 5694
Joined: Mon Sep 14, 2009 7:12 pm
well, it does matter. If you had e.g. 96% H2SO4, whose density is about 1.4 g/ml, you cannot just dilute it twice to get 48%
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

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