What percentage of a radioactive substance remains after two half-lives?

Two liquids are shaken together in a test tube to produce a mixture that quickly separates into two layers. which of the following best describes the behavior of the above pair of substances? soluble insoluble miscible immiscible

Which feature do highland climates have that lower elevation areas do not?

Which formula can be used to calculate the molar mass of ammonia (nh3)? molar mass of n + molar mass of h 3 × molar mass of n + molar mass of h molar mass of n + 3 × molar mass of h 3 × molar mass of n + 3 × molar mass of h