List three characteristics of compounds

A compound is always homogeneous in nature. 

The constituents cannot be separated by simple physical processes.

The formation of a compound is sometimes accompanied by the evolution of energy in the form of heat or light. 

Compounds are made up of 2 or more elements and they are all chemically bonded. The properties of a compound are different from the elements that make it up. Compounds can be broken back into elements by chemical reaction, exposure to light, etc. Compounds can be separated only chemically, not by physical means The mass of the compound is determined by the mass of the elements that make it up. When compounds are formed heat and light is given out or absorbed.