A chemical substance is any material with a known chemical composition. For example, water has the same properties and the same ratio of hydrogen to oxygen whether it came from a river or was made in a laboratory. Typical chemical substances found in the home include water, salt (sodium chloride) and bleach. Generally, substances exist as a solid, a liquid, or a gas, and may change between these phases of matter when there are changes in temperature or pressure.
Gray silicon powder, an element. All the other ones are chemical compounds.
White sodium chloride
Pink hydrated (with water) manganese(II) chloride
Brown manganese(II) carbonate
Black copper(II) oxide
Red hydrated (with water) cobalt(II) chloride
Orange potassium dichromate
Yellow sodium chromate
Green hydrated (with water) copper(II) chloride
Blue hydrated (with water) copper(II) sulfate
Purple anhydrous (without water) chromium(III) chloride