6.3
Compounds
| 6.3 | Compounds |
| Definition |
| A compound consists of two or more elements or compound mixed chemically |
Examples: Water, building blocks and tiles
How metal and non-metal elements combine chemically to form compound
magnesium + oxygen \(\rightarrow\) magnesium oxide
aluminium + oxygen \(\rightarrow\) aluminium oxide
zinc + oxygen \(\rightarrow\) zinx oxide
Methods to Separate Compound
- Compounds cannot be separated physically
- Therefore, compound can only be separated chemically by electrolysis
| Definition |
| Electrolysis is a chemical decomposition of a compound to its elements by passing an electric current through the compound |
Electrolysis of water
 |
- Water consists of hydrogen and oxygen
- Therefore, to separate the hydrogen and oxygen from water, the water must undergo the electrolysis process
| The differences and similarities between physical and chemical changes | |
| Physical | Chemical |
| Does not form a new substance | Forms a new substance that is different from the original substances |
| Examples: Ice melting, water freezing | Examples: Rusting of iron, photosynthesis |
| The properties of the substances remain same | The properties of the substances and poducts are not the same |
| The chemical composition of the substances remain the same | The substances and products have different chemical composition |
| Needs less energy | Needs more energy |
| Occur to matter | |
| Needs energy | |
| The differences between mixtures and compounds | ||
| Mixtures | Differences | Compounds |
| No | Formation of new substances | Yes |
| No | Chemical bond | Yes |
| Physical | Separation method | Chemical |
| Same | Properties of new substances | Different |
