Final answer:
Matter can be classified as pure substances, which are elements or compounds with uniform and definite compositions, or as mixtures, which are combinations of substances that retain their individual properties. Silver is an example of a pure substance that is an element, and air is an example of a homogeneous mixture.
Step-by-step explanation:
When classifying matter, we often categorize it into pure substances and mixtures. A pure substance has a uniform and definite composition. Examples include elements and compounds. A mixture, on the other hand, is a physical combination of two or more substances in which the original substances retain their chemical properties. Mixtures can be homogeneous (uniform composition) or heterogeneous (non-uniform composition).
Classification of Substances
Salt (sodium chloride) is a compound as it is made up of more than one element chemically combined.
Pure water (H2O) is also a compound for the same reason as salt.
Soil typically comprises various organic and inorganic substances and is a heterogeneous mixture.
Salt water, where the salt is dissolved uniformly in the water, is a homogeneous mixture, also known as a solution.
Pure air, which is largely nitrogen, oxygen, and argon, is another example of a homogeneous mixture.
Carbon dioxide (CO2) is a compound formed from carbon and oxygen.
Gold is an element because it cannot be broken down into simpler substances by chemical methods.
Bronze, which is an alloy made from copper and tin, is considered a homogeneous mixture.
To explicitly answer the initial questions:
Silver is a pure substance and more specifically an element.
A homogeneous substance can refer to a pure substance that is the same throughout like elemental silver, or a mixture that is uniform throughout like air or salt water.