Law of Definite Composition
Compounds will have a definite composition.
Ex: H2O will be H2O anywhere.
Law of Multiple Proportions
When two or more compounds with different proportions of the same element can be made.
Ex:CO2(carbon dioxide) --X2--> C2O4(dicarbon tetraoxide)
The Heating/Cooling Curve of a Pure Substance:
Point A:
- Solid: Below melting Point. The particle are closely pock together.The force between is very strong and can be only vibrate at a fixed position.
From A-B:
- Heated: As it is heated, the kinetic energy is converted. Kinetic energy and temperature increase and the molecules vibrate faster at a fixed position.
Point B:
- Melting:The substance will be freezing or melting, depending on the direction.
From B-C:
- In liquid and solid state.
- Temperature is constant because the heat energy is overcoming the forces between particles.
- Constant temperature= melting point
Point C:
- Completely melted; solid turns into a liquid.
- In liquid state- particles move faster and faster.
- Still being heated so temperature and kinetic energy increases.
- Liquid begins to change into gas; molecules start to move around freely.
- Molecules gain enough energy to overcome forces between particles.
- In liquid and gas state.
- Temperature doesn't change. It is called boiling point.
Point E:
- Liquid to gas.
- Gas particles move faster by absorption of energy.
- Heating continues; temperature increases.
