Dilution is a chemical process that belongs in the home and the laboratory. Even children comfortably use this process to prepare soft drink mixes long before they ever enter a science laboratory. Like many other solutions, copper sulfate, with its characteristic blue appearance, can be diluted using standard dilution procedures. Careful measurement is central to the process and determines the accuracy of the dilution. Using the process of dilution, you can quickly convert a concentrated solution of copper sulfate into an array of dilute solutions, each with a known concentration.
Divide the initial concentration of copper sulfate solution by the final concentration you want to achieve by dilution to obtain the dilution factor. For example, if you start with a 1.0 mol/dm^3 concentration and want to end with a 0.1 mol/dm^3 concentration, then the dilution factor is 1.0/0.1 = 10. This ratio is often given as 1:10 and indicates that the final solution is 10 times less concentrated than the solution you start with.
Divide the volume of diluted copper sulfate solution you need by the dilution factor to obtain the unit volume. For example, if you need to make 500 ml of dilute copper sulfate solution using a dilution factor of 10, the unit volume for dilution will be 500/10 = 50.
Measure one unit volume of the starting copper sulfate solution (also called the solute) using a pipette and transfer this unit volume of solute to the flask. For example, if you need to make 500 ml of dilute copper sulfate solution using a dilution factor of 10 and a starting concentration of 1.0 mol/1,000 ml, transfer 50 ml of the 1.0 mol/1,000 ml solute to the flask.
Multiply one less than the dilution factor by the unit volume to obtain the amount of water that should be added to the solute in the volumetric flask. For example, if you need to make 500 ml of dilute copper sulfate solution using a dilution factor of 10, then add (10-1) x 50 ml = 450 ml of water to the solute in the flask.
Close the flask with a stopper and shake to mix the contents thoroughly. The result will be an appropriately diluted solution.
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About the Author
Pearl Lewis has authored scientific papers for journals such as "Physica Status Solidi," "Materials Science and Engineering" and "Thin Solid Films" since 1994. She also writes an education blog entitled Simple Science in Everyday Life. She holds a doctorate from University of Port Elizabeth.
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