MIXTURES
MIXTURES, ELEMENTS AND THEIR ENVIRONMENT
A mixture is a combination of two or more substances put together resulting to a mass.
Mixtures are commonly used in daily life such as soil, coffee and air.
Soil is a mixture of sand, stone, clay, salts and living organisms.
Air is a mixture of different gases such as oxygen, nitrogen, carbon dioxide, water vapour and other gases.
The substances that are combined to form a mixture are called components.
Types of Mixtures
Homogeneous mixture.
It appears uniform to the eyes.
Homogenous mixtures form a uniform composition.
Example, cement is a homogenous mixture of different solids such as limestone, shells and chalk among others.
Other homogeneous mixtures are steel (iron and carbon) and bronze (copper and tin).
Heterogeneous mixture.
Heterogeneous mixture is a mixture made up of a non-uniform composition.
If you take two samples from different parts of the mixture they will not be identical.
For example, you can differentiate rice (solid) from salt(solid) in the mixture.
Other heterogeneous mixtures include salt and sand, sand -sugar, salt -gravel mixtures.
In some cases, two or more substances are mixed together to form a special kind of mixture.
For example, when you mix salt (solid) and water (liquid), the solid seems to disappear in the water. This process is called dissolving and it forms a solution.
When a solid dissolve in a liquid, the liquid is called a solvent and the solid that dissolves is called a solute.
A solution is a special type of mixture that is homogenous and so you cannot tell the difference between the components of a solution.
Water and sand forms a heterogeneous mixture. One can easily separate the sand from water.
Milk (liquid) mixes with water (liquid) completely to form a uniform mixture. Therefore, this mixture is homogeneous.
Oil (liquid) mixes with water (liquid) to form a new substance that is not uniform. Both substances of the mixture can be seen. Therefore, this mixture is heterogeneous.
A gas-gas mixture is comprised of various gases, for example, the air we breathe is a combination of oxygen, nitrogen, carbon dioxide, water vapour and other gases.
The air we breathe is therefore a homogeneous mixture.
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