[alt-photo] Re: Dilution calculation

[Loris Medici]

Jon,

You can use small syringes for measuring small amnts. of solution.
(There are 1ml, 2ml, 5ml, 10ml, 50ml ... syringes.)

I do my calculations based on the dry content of the source solution...

Example:
You need 10ml of 2.5% solution, but you have a 20% solution
1. 10ml x 2.5% (0.025) = 0.25g (This is the dry content of your target
solution...)
2. (x)ml x 20% (0.2) = 0.25g. Therefore (x) = 0.25g / 20% (0.2) =
1.25ml (This is the volume of your source solution which contains the
exact dry amnt. needed for the target solution...)
3. Conclusion: You need 1.25ml 20% solution + 8.75ml (10ml final
volume - 1.25ml source solution) distilled water to mix 10ml 2.5%
solution...

Hope this helps!

Regards,
Loris.


2 Mart 2012 09:52 tarihinde Jon Reid <jon at sharperstill.com> yazdı:
> Dear list,
> Would someone be kind enough to either explain how to work out
> dilution calculations or how to use one of the online calculators?
>
> Several online dilution calculators have units and symbols I don't understand.
>
> I have 20% Na2 and I'd like to create some 2.5% and 5% solutions.
>
> Further, what's a good method for accurately measuring small amounts
> of solution? Do I need a pipette?