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Topic: Increasing the volume of solution lowers experimental error?  (Read 3231 times)

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Offline Macroer

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Increasing the volume of solution lowers experimental error?
« on: April 01, 2010, 03:40:40 PM »

This was part of a lab i preformed to determine rate law for HCl and Mg.

50 mL of 0.5M, 1M, 1.5M and 2M HCl solutions were made using water and this was used with Mg ribbon to find the rate law. The same 0.5M, 1M, 1.5M, 2M HCl solutions were made in 100mL solution that contained water. I was told that the 100mL solution of HCl diluted in water provided more accurate results, than the 50mL solution of HCl dilluted in water. I was wondering why this is the case?


Offline JGK

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Re: Increasing the volume of solution lowers experimental error?
« Reply #1 on: April 01, 2010, 03:53:30 PM »
Probably depends on the volumes of HCl being pipetted to make the solutions. If your using concentrated acid errors in pipetting small volumes will be more apparent in the 50 mL preparations. Errors in preparing 100 mL preps may be reduced as each acid volume required will double.

In general pipetting inaccuracy at smaller volumes is always greater.
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Offline billnotgatez

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Re: Increasing the volume of solution lowers experimental error?
« Reply #2 on: April 06, 2010, 02:20:42 AM »
If you make a solution of 50 ml of water with 10 ml of HCl you get a certain error if you are off by 1 ml of HCl.

You get a different error if you make 100 ml of water with 20 ml of HCl and you are off by 1 ml of HCl.


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