A homogenous mixture, also known as a solution, is a mixture in which the composition is uniform throughout. This means that the concentration of the components is the same at any point in the mixture. An example of a homogenous mixture is salt dissolved in water. The salt molecules are evenly distributed throughout the water, so the concentration of salt is the same at any point in the solution.

A heterogeneous mixture, on the other hand, is a mixture in which the composition is not uniform throughout. This means that the concentration of the components varies from one point to another in the mixture. An example of a heterogeneous mixture is sand and water. The sand particles are not evenly distributed throughout the water, so the concentration of sand is higher in some areas than in others.

Homogenous mixtures can be further classified into colloids and true solutions. A colloid is a heterogeneous mixture in which the particles are larger than molecules but smaller than the particles in a suspension. An example of a colloid is milk. The fat particles in milk are larger than molecules but smaller than the particles in a suspension of sand in water.

True solutions are homogeneous mixtures in which the particles are molecules or ions. An example of a true solution is salt dissolved in water. The salt molecules are evenly distributed throughout the water, so the concentration of salt is the same at any point in the solution.