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Calculating % Inherent Error for Experiment #2 Post-lab Report

Please read lecture guide #1 or the lab manual (p. 23 - 29) on how to calculate % relative error

for various mathematical operations BEFORE you follow the steps shown below. It will help

you to understand the formulations on this handout.

Note: [ ] means that the quantity has a unit of mol/L.

Î”

() means the absolute error of the

equipment. Refer to page 31 for absolute errors in various lab equipment.

(I) % Inherent error (or sometimes refer to as % relative error) for solution 1:

â‚¬

[Solution 1] = Wt. of the Food - dye

Molecular Weight

"

#

$

%

&

' Ã·(Total Volume of the Solution in Liters)

Since the only mathematical operations involved in the above equation are multiplication and

division, we can use the relative error equation that is specific design for multiplication and/or

division as outlined on lecture guide #1 or in the lab manual.

â‚¬

Î” [Solution 1]

[Solution 1] =Î” (Wt. of Food - dye)

(Wt. of Food - dye) +Î” (Volumetric Flask)

100.00mL

Note: we assume that there is no uncertainty in the molecular weight.

(II) % Inherent error for solution 2:

â‚¬

[Solution 2] = [Solution 1] * Pipet Volume

Total Volume of Solution 2

â‚¬

Î” [Solution 2]

[Solution 2] =Î” [Solution 1]

[Solution 1] +Î” (Volumetric Pipet)

10.00mL +Î” (Volumetric Flask)

100.00mL

Note:

â‚¬

Î” [Solution 1]

[Solution 1]

= inherent error for solution 1.

You will need to continue to propagate the error for the remaining solutions until you reach

the final inherent error for the very last solution.

Refer to the procedures in the manual and your lab notebook for the specific volumes of pipet

and volumetric flask that you use in each step.

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