We defined chemistry at the beginning of the chapter as the study of matter and changes it undergoes. First, we would like to show you a simple graphic diagram that represent this lesson.

Matter is anything that occupies space and has mass.
Example: water, earth, trees, and air.


Substance is a form of matter that has a definite (constant) composition and distinct properties. It can be defined by their appearance, smell, taste, etc.
Example: water, ammonia, table sugar (sucrose), gold, and oxygen.


Mixture is a combination of two or more substances in which the substances retain their distinct identities. Example: air, milk, cement, soft drinks

Mixture are either homogenous or heterogeneous.
Homogeneous: mixture in which the composition of the mixture is same throughout / uniform
Heterogeneous: mixture in which the composition of the mixture is not uniform


Element is a substance that cannot be separated into simpler substances by chemical mass.


Compound is a substance composed of atoms of two or more elements chemically united in fixed proportions.

Chemists use symbols of one or two letter to represent the elements. The first letter is always ‘capitalized’, and any following letters not. For example: Co is the symbol for element cobalt, whereas CO is the formula for carbon monoxide molecule.


The Three States of Matter
A substance in principle can exist in three states: solid, liquid, and gas.


The three states of matter can be interconverted without changing the composition of the substance.

Physical and Chemical Properties of Matter
Physical properties are any properties that can be measured and observed without changing the composition or identity of substances.

Here are some examples of physical properties:

  • color
  • density
  • melting point
  • concentration, etc

Chemical properties are any properties that changing the chemical/ composition/ identity of substances that we cannot recover.

Here are some examples of chemical properties:

  • reactivity with other chemicals
  • toxicity
  • coordination number
  • flammability
  • enthalpy of formation
  • heat of combustion
  • oxidation states
  • chemical stability
  • types of chemical bonds that will form



Chang,Raymond. 2010.”Chemistry, 10th Edition”. New York, Mc-Graw Hill
Flammability Class B1 Vertical Shaft Furnace at Technische Universität Braunschweig Germany