Chemistry 160
Pre-Lab Questions for Laboratory 3
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1. Briefly define the following terms:

Accuracy:

Precision:

Systematic (determinate) error:

Random (indeterminate) error:

Confidence interval:

2. What is the relative standard deviation in a volume of 20 mL using a buret if the standard deviation is 0.05 mL?

3. The Food and Drug Administration (FDA) tolerance for mercury in foods is 0.5 ppm (0.5mg/kg). A 300.0 g sample of fish from Lake Erie was found to contain 0.16+0.05 mg of mercury. (a) Calculate the ppm of Hg in the fish. (b) Show by calculation whether the fish exceeds FDA standards. (That is, determine the confidence limits and see if the mercury level is greater than the FDA limit by an amount larger than the confidence limits.)