Pure Substances vs. Mixtures
* Pure Substance: A pure substance is made up of only one type of particle. It has a fixed composition and consistent properties throughout. Examples: water (H₂O), gold (Au), table salt (NaCl).
* Mixture: A mixture contains two or more different substances that are physically combined. The substances in a mixture retain their individual properties. Examples: saltwater, air, soil.
Why Mixtures Aren't Pure Substances
Mixtures are not pure substances because:
* Variable Composition: The proportions of the different components in a mixture can vary. For example, a cup of coffee can be strong or weak depending on how much coffee grounds are used.
* No Fixed Properties: The properties of a mixture are determined by the properties of the substances it contains. For instance, the color of saltwater depends on how much salt is dissolved in the water.
* Components Can Be Separated: The components of a mixture can be separated by physical means, like filtration, evaporation, or magnetism.
Think of it like this: Imagine you have a bowl of fruit. The fruit is a mixture because it contains different types of fruits, each with its own unique properties. You can easily separate the fruits from each other. This is unlike a pure substance like sugar, which is made up of only one type of molecule and can't be separated into simpler components.
Let me know if you'd like more examples or have other questions about pure substances and mixtures!
