Final answer:
Matter is classified as pure substances or mixtures, with pure substances including elements and compounds, and mixtures being either homogeneous or heterogeneous based on uniformity of composition.
Step-by-step explanation:
Matter can be classified as either a pure substance or a mixture. Pure substances have a constant composition and properties throughout the sample. There are two types of pure substances: elements and compounds. An element is a substance made of one type of atom, while a compound consists of two or more types of atoms chemically bonded together. On the other hand, mixtures are physical combinations of two or more substances that retain their individual properties. Mixtures can be classified further into homogeneous mixtures or heterogeneous mixtures. A homogeneous mixture has a uniform composition throughout, like salt water, whereas a heterogeneous mixture has a non-uniform composition, like soil.
For example:
- Salt is a compound because it is composed of more than one type of atom chemically bonded together.
- Pure water is a compound as it is made up of hydrogen and oxygen atoms in a fixed ratio.
- Soil is a heterogeneous mixture because it comprises different substances that are not uniformly distributed.
- Saltwater is a homogeneous mixture; it has a uniform composition throughout.
- Pure air is a homogeneous mixture of different gases.
- Carbon dioxide is a compound with a fixed ratio of carbon to oxygen atoms.
- Gold is an element as it is composed of only one type of atom.
- Bronze is a heterogeneous mixture of copper and other metals.