Which type(s) of matter would need to be separated by chemical methods?

solids, liquids, gases, or plasma

Explanation:

In chemistry, a chemical substance is a form of matter that has constant chemical composition and characteristic properties. It cannot be separated into components without breaking chemical bonds. Chemical substances can be solids, liquids, gases, or plasma

a boiling water reactor does not boil the water. a pressurized water reactor boils the water faster. a pressurized water reactor is heated directly by the core. a pressurized water reactor does not use fission.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.