Expert Answers Hover for more information. When two or more compounds are mixed together but not chemically combined the result is called a mixture. Unlike a pure substance (element or compound), a mixture can have variable composition. Mixtures that are evenly distributed throughout are called homogeneous.

The ions or molecules in two solutions can react to form a solid. A solid formed from two solutions is called a precipitate.

A precipitate is a solid formed in a chemical reaction that is different from either of the reactants. This can occur when solutions containing ionic compounds are mixed and an insoluble product is formed. The identity of the precipitate can often be determined by examining solubility rules.

Physical properties of a substance are characteristics that can be observed without altering the identity of the substance. Color, odor, density, melting temperature, boiling temperature, and solubility are examples of physical properties. Physical properties can be used to identify a pure substance.

Ice, iron, hydrochloric acid, calcium oxide, mercury are pure substances as they have definite composition.

They are: Pure Substance: The substances that are free from any kind of mixture and contain only one kind of particle are pure substances. Examples of pure substances include iron, aluminum, silver, and gold.

Examples of pure substances include tin, sulfur, diamond, water, pure sugar (sucrose), table salt (sodium chloride) and baking soda (sodium bicarbonate). Crystals, in general, are pure substances. Tin, sulfur, and diamond are examples of pure substances that are chemical elements.

This includes distilled water, mineral water, spring water, still water, sparkling water, seltzer water, and plain bottled water. Distilled water is tap water that had been boiled to steam. The steam is collected and condensed back into the liquid without impurities, chemicals, and minerals.

Example of pure substance are as follows: Sugar. Water. Baking soda. Salt.