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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: student8607 on November 06, 2008, 07:23:41 PM

Title: How to....prepare a solution?
Post by: student8607 on November 06, 2008, 07:23:41 PM

In the chapter review, there were a few questions about how to prepare solutions? We never discussed this and I couldn't find anything in the book to help?

Describe how to prepare a solution of known molarity by dissolving a solid in a solvent?

Describe how to prepare a solution of known molarity by diluting a more concentrated solution?


I'm familiar with the equations but now these q's.

Title: Re: How to....prepare a solution?
Post by: Borek on November 07, 2008, 03:15:40 AM

Quote from: student8607 on November 06, 2008, 07:23:41 PM

I'm familiar with the equations but now these q's.

Thee questions are just about practical application of the equations you know.

Say you are asked to prepare 200 mL of 0.5M NaCl solution.

First, calculate mass of NaCl that will be present in the solution - that can be done with the equations you alredy know.

Weight correct amount of NaCl.

Dissolve in some smaller amount of water than target volume.

Fill up to 200 mL.

You can't use 200 mL of water, as the final volume will be higher and the final concentration will be in effect lower.