How to Calculate Concentration If Concentration Units Are Not Specified

If concentration units are not specified, when given a percent It is usually always volume per volume for liquids and grams per mL for dissolved solids. ( grams / 100 mL) * 20 mL = grams of Bromophenol blue in 20 mL of water makes % (mass/volume) bromophenol blue. The dye is not very soluble. But your solution will be really blue.