Mixtures:
* No fixed ratio: The components of a mixture can be combined in any proportion. For example, you can make a salty solution with a little salt or a lot of salt.
* No chemical change: The substances in a mixture retain their individual properties. Salt dissolved in water is still salt and water.
* Easily separated: The components of a mixture can usually be separated by physical means like evaporation, filtration, or magnetism.
Compounds:
* Ratio fixe: A compound always contains the same elements in a fixed ratio by mass. For example, water (H₂O) always has two hydrogen atoms and one oxygen atom.
* Chemical change: A compound is formed when two or more elements combine chemically. The resulting compound has properties distinct from the original elements.
* Difficult to separate: To separate a compound into its elements, you need to break the chemical bonds, which requires chemical reactions.
Exemple:
* Mélange: A salad is a mixture of different vegetables. You can add more or less of each ingredient, and they all retain their individual properties. You can easily separate the salad by picking out the different vegetables.
* Compound: Water (H₂O) is a compound. It always has a 2:1 ratio of hydrogen to oxygen. It has properties different from hydrogen and oxygen (it's liquid at room temperature, for example). You can't separate water into hydrogen and oxygen by simple physical means.
en résumé: Mixtures allow for flexibility in composition because the substances are not chemically bonded. Compounds have a fixed ratio of elements due to the chemical bonds that hold them together.
