# Changes in the State of Matter

### Changes in the State of Matter

1. Matter is anything that occupies space and has mass.

2. Matter exists in 3 states, namely the solid state, liquid state and gaseous state.

3. We can catagorise matter into 2 categories: element and compound.

4. Element is the substance that consists of 1 type of atom. Compound is the substance that consists of more than 1 type of atom.

5. Matter is made up of a large number of tiny and discrete particles. We can catagorise the particles into 3 categories: The atoms, the molecules and the ions.

6. Atom is the smallest, indivisible particle of an element. Atoms of the same element are exactly alike and are different from the atoms of all other elements.

7. When 2 or more atoms join together chemically, they form molecule. For example, 2 hydrogen atoms join together form a hydrogen molecule. 1 oxygen atom combine with 2 hydrogen atoms form a water molecule.

8. Ions are any particles that carry charge. For example, if a hydrogen atom is charged and carries a +1 charge, it become a hydrogen ion. Also, if an oxygen ion is charged with a charge of -2, it become an oxygen ion.

9. Ions that carry positive charge are called cations. Ions that carry negative charge are called anions.

### Kinietic Theory of Matter

The kinetic theory of matter explains the state of matter in solid, liquid and gaseous states based on the following assumptions:

1. Matter is made up of very small particles, each of which has a mass.

2. These molecules are in constant, random motion. The rapidly moving particles constantly collide with each other and with the walls of the container.

3. There are forces of attraction between particles of matter. These attraction forces will increase as the distance between the particles becomes closer.

4. The average kinetic energy of the gas particles depends only on the temperature of the system. The higher the temperature, the higher the kinetic energy of the particles.