P3.9—Quantitative practical procedures

Titration measures a reacting volume; rate experiments follow change with time; gravimetry measures mass after heating to constant mass; thermometry measures temperature change; gas experiments measure volume under stated conditions.

Use rough titration first, then repeat to concordance; heat a solid to constant mass; collect gas over water while accounting for water vapour where required.

In a titration, rough titre locates the endpoint, then concordant titres are averaged. In gravimetry, constant mass shows that further heating no longer changes the measured residue.

The same “repeat twice” rule does not replace the specific endpoint, constant-mass or gas-correction criterion for each method.