# Quantitative and Qualitative

## Key Questions

• Qualitative methods usually make a YES/NO determination of some type, whereas quantitative methods provide a numerical estimate of a quantity, including uncertainties.

For example, a qualitative test for the presence of lead make cause a solution to turn yellow if a significant quantity of lead ions is present in solution, whereas a quantitative test might say that lead is present in a sample at a concentration of $2.6 \pm 0.5$ mg/L.