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Dilutions from Stock Solutions

Chemistry Quick Review of Dilution Calculations

By , About.com Guide

If you're working in a chemistry lab, it's essential to know how to calculate a dilution. Here's a review of how to prepare a dilution from a stock solution.

You use the law of conservation of mass to perform the calculation for the dilution:

MdilutionVdilution = MstockVstock

As an example, say you need to prepare 50 ml of a 1.0 M solution from a 2.0 M stock solution. Your first step is to calculate the volume of stock solution that is required.

MdilutionVdilution = MstockVstock
(1.0 M)(50 ml) = (2.0 M)(x ml)
x = [(1.0 M)(50 ml)]/2.0 M
x = 25 ml of stock solution

So to make your solution, you put 25 ml of stock solution into a 50 ml volumetric flask. Dilute with solvent to the 50 ml line.

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