chemical changes and physical changes

Physical changes are not marked with the formation of new substances. While chemical changes indicated by the formation of new substances.
More physical changes we know as being a change agent. In the form of the substance changes, no new substance is formed. Although the substance has changed his form but still has a chemical formula of the same molecule. Various kinds of physical changes:



1. Melting: changing the form of a substance from solid to liquid.
2. Yawning: a substance changes from liquid form to gas.
3. Sublime: changes in gas form to the substance of the solid / vice versa.
4. Condense: changes in substance from the gas form into the liquid.
5. Frozen: changes in substance from liquid form to solid.

Change the ice melts into water are examples of physical changes. Ice and water have the same molecular formula, which is H2O, so that no new substance is formed.

Chemical change known as chemical reactions characterized by several features:

1. discoloration.
2. temperature changes.
3. emergence of sediment.
4. emergence of gas.

In the combustion of gasoline there is a process of chemical change. If we assume gas consisting of octane, gasoline combustion reaction:
8 CO2(g) + 4 H2O(g)">C8H8 (g) + 12 O2 (g) ----> 8 CO2 (g) + 4 H2O (g)
karbondioksida + uap air">gasoline + oxygen ----> carbon dioxide + water vapor
Seen that the new substance is formed of carbon dioxide and water vapor molecules have a different formula with the initial substances and oxygen gas.