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Increasing the volume of solution lowers experimental error?

  1. Apr 1, 2010 #1
    1. The problem statement, all variables and given/known data

    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?

    2. Relevant equations

    3. The attempt at a solution
    Don't have that great an idea, but the increased volume of solution provides more surface area for reaction, therefore greater results?
    Last edited: Apr 1, 2010
  2. jcsd
  3. Apr 1, 2010 #2
    What happens to the relative uncertainty in your volume measurements when you use larger volumes?
    (Note this also depends on the absolute uncertainty your measuring device produces. Switching from a 10 mL volumetric pipet to a 1000 mL beaker to measure volume is not advisable!)
  4. Apr 1, 2010 #3
    This wasn't the case as the same measuring device, with the same scale was used in both 50mL and 100mL
  5. Apr 1, 2010 #4
    Correct. Now if you measure 50 mL and 100 mL quantities on the same measuring device, the absolute error is the same for both sets of measurements. Which set of measurements will have the smaller relative error and why?
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