Mixtures and pure substances are different in important ways. Let’s break down their differences:

1. Composition:

   • Pure Substances: These are made up of just one kind of particle.
     • This can be something simple, like an element (for example, gold, which is represented as ( \text{Au} )).
     • Or it can be a compound, like water, which is written as ( \text{H}_2\text{O} ).
   • Mixtures: These include two or more different kinds of particles.
     • For example, air is a mixture of various gases.
     • Another example is a salad, which has different kinds of vegetables mixed together.

2. Properties:

   • Pure Substances:
     • They have steady boiling and melting points.
     • For instance, pure water boils at (100^\circ C) under normal conditions.
     • They show particular physical and chemical traits.
   • Mixtures:
     • Their boiling and melting points can change.
     • For example, the boiling point of saltwater depends on how much salt is in it.
     • The properties of a mixture can change based on the amounts of its parts.
     • For instance, a solution with 10% salt will behave differently than one with just 5% salt.

3. Separation:

   • Pure Substances: You can't break them down into other substances using physical methods.
   • Mixtures: You can separate them using physical methods.
     • This could mean using tools like filters or special processes like distillation.

In summary, understanding these differences helps us know how to work with various materials in science!