Zusammenfassung der Ressource
Compound and Mixtures
- Elements and Compounds
- An element contains only one type of atom.
- A compound contains different types of atoms joined together.
- The formula of a substance tells us the number of each type of atom present in the substance.
- The properties of a compound are different from those of the elements which it contains.
- A compound is a pure substance which is made of the same particles.
- A sample of a compound will always have the same elements present in the same fixed proportions.
- Compounds and Mixtures
- Compounds will react chemically to make new substances.
- You can tell that a compound has reacted by observing what happens to it.
- A mixture is formed when two or more substances are added together.
- Air is a mixture of gases that can be separated into pure substances.
- Air consists of nitrogen, oxygen, argon (and other noble gases), carbon dioxide and water vapour.
- Each of the gases found in air has important uses.
- Air can be liquefied and then
individual gases can be
separated by fractional
distillation.
- Sea water and mineral water are other examples of mixtures.
- Elements and Mixtures
- Elements and compounds melt and boil at a certain temperature.
- Mixtures do not melt or boil at one particular temperature.
- The melting point and boiling point of a mixture change as the composition of the mixture changes.