Difference Between Mixture and Compound With Examples
In chemistry, a mixture and a compound are two different states of a substance. In this post, we will learn about these two states and try to find out what is the difference between a mixture and a compound. We will also try to find out, why water is a compound and air is a mixture.
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Definition of a mixture-
The mixture is an impure substance formed by mixing two or more pure substances (elements and compounds) in any proportion, such that they do not undergo any chemical change and retain their individual property.
To learn more about the mixture, click here
Definition of Compound –
A compound is a substance formed when two or more elements combine chemically in a fixed ratio.
To learn more about the compound, click here
DIFFERENCE BETWEEN MIXTURE AND COMPOUND WITH EXAMPLES
Six (6) basic differences between mixture and compound are as follows:
01. PURITY
A mixture is an impure substance formed by mixing two or more pure substances, whereas a compound is a pure substance.
For example, air (a mixture) is an impure substance as it contains molecules of different gases. The air consists of oxygen (O2), nitrogen (N2), carbon dioxide (CO2), Argon (Ar), water vapor, etc. in varying proportions. Whereas, water (a compound) is a pure substance as it contains only molecules of water(H2O).
Example of Mixture and compound
02. PROPERTIES
Components of a mixture do not combine chemically, therefore they retain their chemical and physical properties. Whereas, the compound is a completely new substance with properties entirely different from that of its components.
For example, a molecule of water (H2O) which is a compound has two atoms of hydrogen (H) and one atom of oxygen (O). Water is liquid under normal conditions while hydrogen and oxygen are gases. A mixture of hydrogen and oxygen when ignited creates fire while another way round we use water for extinguishing a fire.
03. HOMOGENEITY
The mixture may be homogeneous or heterogeneous, whereas the compound is always homogeneous as it contains molecules of the same kind.
For example, water has the same properties throughout, thus it is homogeneous. Whereas the mixture of salt and water is homogeneous and that of rice and pulse is heterogeneous.
04. COMPOSITION
In mixtures, the ratio of components can vary. Whereas in the case of a compound, the components are present in a fixed ratio by weight.
For example, we can prepare a mixture of sand and common salt either by mixing 1 gm of salt with 2 gm of sand, or 2 gm of salt with 2 gm of sand. Whereas, we get water, a compound only when hydrogen and oxygen atoms combine chemically in a fixed ratio of 1:8 by mass.
05. SEPARATION
We can separate components of a mixture by simple physical methods. Whereas, we cannot separate the components of a compound by simply physical means. In compounds, chemical bonds join atoms together. These bonds are very strong and difficult to break. Thus, to get original elements (or atoms) from compounds we need to apply chemical methods.
For example, to separate salt from the salt solution, we can do it simply by evaporation. Whereas, to break the molecule of water into its elements hydrogen and oxygen, we need to pass an electric current through it.
Interesting home experiment by sciencefix to observe the breaking down of water into its components hydrogen and oxygen by passing an electric current through it.
06. ENERGY CHANGES
The formation of a mixture does not involve any change in energy, whereas the formation of a compound always results in the absorption or release of energy.
For example, during the formation of an aqueous sugar solution, no release or absorption of energy takes place. Whereas, water forms during the combustion of hydrogen gas in the presence of oxygen, which results in the release of a huge amount of energy.
DIFFERENCE BETWEEN MIXTURE AND COMPOUND IN TABULAR FORM
Difference between mixture and compound
WHY IS WATER A COMPOUND AND AIR A MIXTURE?
Earlier, water and air were thought to be elements. But, later on, it was proved that while water is a compound, the air is a mixture. Here is a list of some evidence to prove the fact.
- Water is a compound because hydrogen and oxygen in water chemically combine in a fixed ratio of 1:8 by mass. Whereas, the main components of air are nitrogen, oxygen, carbon dioxide, and water vapor, which are not chemically combined. Thus, the air is a mixture.
- The chemical composition of water does not vary due to the change of source, whereas the composition of air varies from place to place. During the rainy season, the air becomes humid due to the presence of more water vapor. some impurities like sulfur dioxide, hydrogen sulfide, etc. also change their composition in some places.
- Water is a compound because its properties are completely different from that of hydrogen and oxygen. The oxygen present in water does not support combustion. Whereas, the air is a mixture as components of air retain their individual properties. For example, oxygen present in air supports combustion.
- During the formation of a compound, energy change takes place and the same happens during the formation of water. A mixture of hydrogen and oxygen when ignited releases a huge amount of energy to form water. Whereas, no energy change occurs when components of air are mixed. Thus, the air is a mixture.
- We can represent water by the chemical formula (H2O), whereas the same is not possible with air.
Why is water a compound and air a mixture?
