Classification of Matter Review

A compound is a substance formed when two or more elements chemically bond together in a fixed ratio. Example: Water (H2O) is a compound made of hydrogen and oxygen.

A mixture is a combination of two or more substances that are not chemically bonded. Example: Salad is a heterogeneous mixture of various ingredients.

An element is a pure substance that cannot be broken down into simpler substances by chemical means. Example: Oxygen (O) is an element.

A pure substance is a material that has a constant composition and consistent properties throughout. Example: Table salt (NaCl) is a pure substance.

A heterogeneous mixture is a mixture in which the components are not uniformly distributed, and different parts can be seen. Example: A bowl of cereal.

A homogeneous mixture is a mixture in which the components are uniformly distributed, and it appears the same throughout. Example: Sugar dissolved in water.

A chemical change is a process that involves the transformation of one or more substances into different substances. Example: Iron rusting.

A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition. Example: Ice melting.

A chemical change results in the formation of new substances, while a physical change does not change the chemical identity of a substance.

An example of a chemical change is digesting food, where complex substances are broken down into simpler substances.