A student calibrates a spectrophotometer at a fixed wavelength using five standard…
CHEMISTRY · Multi-part · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
A student calibrates a spectrophotometer at a fixed wavelength using five standard solutions of the same compound. A plot of measured absorbance (vertical axis) versus prepared concentration (horizontal axis, units molL−1) yields a best-fit line with the equation A=1.87c+0.052
Ideally, the intercept would be zero.
(a) Describe TWO distinct experimental factors that could produce a positive, non-zero intercept in this type of calibration plot.
(b) For EACH factor identified in part (a), explain how it would influence the accuracy and precision of concentration values subsequently obtained for unknown samples using this calibration curve.