A chemical test is a procedure used to identify and quantify the presence of a particular substance in a sample. LITMUS is a type of chemical test that uses a dye to indicate the acidity or alkalinity of a solution. An ASSAY is a type of chemical test that measures the amount of a particular substance in a sample. Titrate is a type of chemical test that measures the concentration of a particular substance in a solution by adding a known volume of a reagent.