A1.20 gram sample of a hydrated salt is heated to a constant mass of .80 gram. what is the percent of mass of water contained in the original sample

Iknow #2 is d. i just need to know why

What approach is required to balance the objectives of sustainable development? balancing the objectives of sustainable development requires a(n) .

Ageochemist examines a piece of metal that he found in the soil. he performs tests to identify the metal from its density, electrical conductivity, and melting point. which statement best describes his investigation? a. he is determining physical properties that are sufficient to identify the metal. b. he is determining chemical properties that are sufficient to identify the metal. c. he is determining physical properties that are insufficient to identify the metal. d. he is determining chemical properties that are insufficient to identify the metal.