What is meant by a pure substance? Name two pure substances.

Answer:

Explanation:

A pure substance is a substance that consists of only one type of particle, either atoms, molecules, or ions, and has a consistent and uniform composition throughout. Pure substances cannot be separated into other substances by physical means. They have well-defined chemical properties and distinct physical properties, such as melting point and boiling point.

Two examples of pure substances are:

Elemental Hydrogen (H2): Elemental hydrogen consists of diatomic molecules, each containing two hydrogen atoms bonded together. It is a pure substance because it consists only of hydrogen molecules and cannot be separated into other substances without chemical reactions.

Water (H2O): Water is a pure substance composed of water molecules, each consisting of two hydrogen atoms and one oxygen atom bonded together. It is also a pure substance because it has a consistent and uniform composition throughout and cannot be separated into other substances without breaking its molecular bonds.

These examples illustrate the concept of pure substances, where the composition is homogeneous and consistent throughout the entire sample.