Definition: Matter is anything that has mass and occupies space. Examples are stone, water, air etc. Matter is made up of very tiny particles such as atoms, ions and molecules.
States of Matter
Matter exists in three main physical states which are solid, liquid and gas. Examples of solids are stone, wood, paper etc. Examples of liquids are water, oil, kerosene etc. Examples gases are air, oxygen, hydrogen etc.
Plasma is often called “the fourth state of matter” along with solid, liquid and gas. Just as a liquid will boil, changing into a gas when energy is added, heating a gas will form a plasma.
Change of State
A change of state is brought about by a change in temperature i. e heating and cooling. When a substance is heated, its particles acquire more kinetic energy and when it is cooled, the particles loose kinetic energy.
Properties of Solids
- Solids have definite shape, size and volume
- The particles of solids are very close
- The particles of solids are held together by a very strong electrostatic force of attraction
- Free movement of particles cannot take place in solids
- Solids are in-compressible and very dense
Properties of Liquids
- Liquids have definite volume
- They do not have definite shape but they take the shape of their containers
- The particles of liquids are less closed
- The particles can move about within a restricted space
- Liquids are in-compressible and less dense
Properties of Gases
- Gases have no definite volume
- They have no definite shape and always take the shape of their container
- Gaseous molecules are not hold together by any force of attraction
- Gas molecules can move about randomly and at great speed
- Gases are compressible and least dense.
Physical Properties of Matter
These are properties which are associated with the physical changes of matter. These properties do not cause any change in the composition of matter. The physical properties of matter are;
- Boiling point: This is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapour. For example, the boiling point of water is 100 oC.
- Melting point: This is the temperature at which solid turns to liquid.
- Density: This is the ratio of the mass to volume
- Hardness: The is the property of being rigid and resistance to pressure by substances
- Malleability: This is the ability to beat a substance to sheet
- Ductility: This is the ability of a substance to be drawn into wire.
- Electrical conductivity: Ability to allow the passage of electrical current
- Crystalline form: This is the definite pattern of arrangement of atoms and other particles in a solid substance
Other physical properties are colour, odour and taste.
Chemical Properties of Matter
These are properties which describe the chemical reactions or composition of matter. These properties include:
- Flammability: This refers to whether a compound will burn when exposed to flame or not
- Toxicity: This is the degree to which a substance is poisonous
- Chemical stability: This refers to the potential changes in composition in the product due to chemical reactions that may occur, such as oxidation, polymerization, and hydrolysis.
- Acidity: This is a measure of a solution’s capacity to react with a strong base
- Alkalinity: This is a measure of a solution’s capacity to react with a strong acid
- Oxidation states: This is the total number of electrons that an atom either gains or loses in order to form a chemical bond with another atom