Effects of Determinant Errors

Constant error example: A scale is off by +5 mg. What are the errors produced with 15 mg and 1.5 g weighings?

The error could have been reported as parts-per-thousand (´ 10³) (ppth), parts-per-million (´ 10⁶) (ppm), parts-per-billion (´ 10⁹) (ppb), parts-per-trillion (´ 10¹²) (ppt), in addition to the parts-per-hundred (´ 10²) (%). Since the number is a weight ratio, one should use the convention, (w/w), to indicate this. This avoids confusing the result with that obtained with volumes, (v/v), or moles, (mol/mol).

For example, the error in the 1.5 g object measurement, in ppth, is

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This page was created by Professor Stephen Bialkowski, Utah State University.

Monday, August 28, 2006