PHYSICAL CHANGE AND CHEMICAL CHANGE

B. PHYSICAL CHANGE AND CHEMICAL CHANGE

1. Physical change

The characteristic of physical change:

·         Substance which have changed can regain its initial form ( zat yang berubah dapat kembali seperti semula)

·         In a physical change no new substanceare formed

·         A physical change followed by the change in physical properties

2. Chemical change

The characteristic of chemical change:

·         Substance which have changed are difficult or impossible to regain their initial formed  ( Tumbuh zat yang baru )

·         In chemical change, new substance are formed

·         A chemical change is followed by a chemical reaction

3. Chemical reaction

Chemical reaction is indicated by the occurrence of the change colour, sediment, gases, or the change temperature.

One example or chemical reaction indicated by change in colour is reaction of whitewash and sulfuric acid.

The sediment formation, example:

HCL+NaOH                               NaCl+H₂O

The symptom of a gas formation, example:

Magnesium+HCl                           ligh green solution + Hydrogen gas

The change in temperature, Example

The reaction of carbide and water.