What is a Mixture? What are the kinds?
A mixture can involve two or more substances of the same phase or different phases. For example, you can mix water and sand (liquid and solid), sugar and salt (a solid and another solid), water and oil (liquid and liquid), or nitrogen and oxygen (gas and gas). Mixtures can vary a lot and can be homogeneous or heterogeneous.
Mixtures involve mixing substances, so let us first be clear about what a homogenous substance is. When a sample of matter has the same composition throughout, we call that substance a homogeneous substance. A cup of water will have the same chemical composition throughout (H2O). That makes it a homogeneous substance. A piece of gold will also have the same chemical composition, making it a homogenous substance. Homogeneous Mixtures behave similarly — the substance formed appears to have the same chemical composition. Alloys and Solutions are Homogeneous mixtures.
A mixture can also result in two or more phases separated by boundaries. Very often, the separation can be seen by the eye. A heterogeneous mixture is one that does not have uniform properties and composition. Take a look at a bowl of cereal with nuts. A spoon full will surely have a different number of nuts than a second spoonful taken at random. Another example—take some sea-sand into your palms. Look at it closely and you will notice that some sand particles are bigger than others, and the colors of some particles may be different too. They are NOT uniform in any way!
Heterogeneous mixtures include colloids, emulsions, or suspensions.
Click on the above heterogeneous mixtures to learn more about them.