02 Structure of Atom
03 Formular and Equations
04 Periodic Table
05 Chemical Bond
06 Electrochemistry
07 Acids and Bases
08 Salts
09 Manufactured Substances in Industry
10 Rate of Reaction
11 Carbon Compounds
12 Oxidation and Reduction
13 Thermochemistry
14 Chemicals for Consumers

2.1.2 Changes in the State of Matter

3 States of Matter

Matter exists in 3 states of matter, namely, solid state, liquid state and gaseous state.

Characteristics of Matter in Solid, Liquid and Gaseous State

Arrangement of Particles

Solid
Particles are arranged in an orderly manner and close to one another.
Liquid
Particles are not arranged in order. The space between particles is moderately large.
Gas
The particles are very far apart and randomly arranged.
Movement of Particles
Solid Particles vibrate at fixed positions.
Liquid Particles move randomly and slowly and sometimes will collide against each other.
Gas The particles move randomly in all directions at great speed.

The force of Attraction Between Particles

Solid very strong
Liquid Strong but weaker than in the solid state.
Gas very weak

Ability to be compressed

Solid Very difficult to be compressed because the particles are packed closely.
Liquid Not easily compressed because the particles are packed quite closely.
Gas Easily compressed because the particles are very far apart.

Heat Energy content

Solid Lowest Energy Content
Liquid Moderate energy content.
Gas Highest energy content
Volume and Shape
Volume Shape
Solid Fixed Fixed
Liquid Fixed Follows the container
Gas Follows the container Fills the whole container

Inter-conversion between the States of Matter

Change in Heat and Kinetic Energy of Particles

  1. The change in temperature will influences the kinetic energy or the speed of the motion of the particles.
  2. When a substance is heated, the kinetic energy of the particles in the substance increases. This causes the particles to move or vibrate faster.
  3. Likewise, when a substance is cooled, the kinetic energy of the particles in the substance decreases. This causes the particles to move or vibrate slower.
  4. The kinetic energy of the particles in a substance is directly proportional to the temperature of the substance.
Inter-conversion between States of Matter

Heating Curve

 
The graph above shows the heating curve of a substance.

Cooling Curve


The graph above shows the cooling curve of a substance.

Melting Point, Boiling Point and State of Matter

  1. The physical state of a substance at a certain temperature and pressure depends on the values of its melting and boiling points.
  2. A substance is in solid state if it exists at a temperature below its melting point.
  3. A substance is in liquid state if it exists at a temperature above its melting point but below its boiling point.
  4. A substance is in gaseous state if it exists at a temperature above its boiling point.