Chemistry has always been an interesting subject about several substances, matters and its properties. It always studies about how and why a particular substance is combined with the other and the separated from the other. Chemistry is something that we don every day is our life. If we add salt in water and cook a food, it is also chemistry. All the materials around us and even our own body are made up of matter.
Chemistry has always been seen as combining various fluids and substances inside the laboratory. In reality combining of different materials and substances is a part of chemistry. Whenever two substances are physically combined together in order to form a distinct material, it is termed as a mixture. Mixture generally takes place in the form of solutions and suspensions. It is required to be very clear that a mixture is a physical combination and not a chemical combination. Unlike the chemical combinations mixtures can be separated by using several physical methods. The change in the energy is minute or zero in case of mixtures and can have variable compositions. In case of chemical combinations the compositions are generally fixed and definite. In case of a mixture the individual properties of the substances are retained whereas in case of a chemical combination the properties of the material formed changes totally.
Mixtures can be classified into Homogeneous Mixtures and Heterogeneous Mixtures. In this description concept about heterogeneous mixture has been described in details. A mixture that contains a variable proportion of solid, liquid or gas substances are called as heterogeneous mixture. It is that form of the mixture in which the composition is not the same throughout. The components of a heterogeneous mixture have localized regions that possess different properties. The substances within the mixture always maintain their individual properties. Heterogeneous mixtures can be separated very easily with the help of physical means. This form of mixtures can be made up from three phases of matter – solid, liquid and gas. Different mixtures are given different names. If a solid is mixed with a liquid and a liquid is combined with another liquid, the two materials produced will have different names. The names that are commonly in use are –
i. Suspension – It is a mixture of a solid substance with a liquid substance. Example- ORS is an oral suspension where a powder is mixed with water.
ii. Smoke- The combination of solid and gas forms smoke.
iii. Emulsion- It is the combination of two liquid substances. When oil and water are mixed together it is an example of emulsion. Emulsion paints are also one common example.
iv. Aerosol – It is the combination of liquid and gas. All kind of fizzy drinks or carbonated drinks are examples of aerosols.
Understanding mixtures requires a great deal of analysis and exploration. There can be a number of mixtures that is taking place in our daily life. Identification of mixtures therefore requires sound knowledge on mixtures and its types. The difference between the various kinds of mixture is also to be known for better identification of mixtures. Homogenous mixture is a mixture where all the components are in a single phase. All the components in case of a homogeneous mixture are in the same proportion throughout the composition. A homogenous mixture is not generally separable easily. In case of heterogeneous mixture the case is different. The components are not in the same proportion and the mixture can also be separated easily. Therefore the first identification point of any heterogeneous mixture is that it can be separated easily. In case of a homogenous mixture one single phase is formed whereas in case of heterogeneous mixtures different phases are formed. If we consider a bronze, which is a mixture of tin and copper we can see it as a single substance. Whereas if mixture of oil and water can be seen, we can see two different layers being formed. These different layers are different phases. Therefore the second identifier of heterogeneous mixture is that these mixtures have different phases.
Examples of Heterogeneous Mixtures:
It is evident from the above discussions that heterogeneous mixture contains a number of phases along with it. These phases are easily visible with our naked eyes. There are several kinds of heterogeneous mixtures that we come across in our daily lives. The examples of few such mixtures are given as follows:
If we consider only mixture of the solid substances –
i. Mixed Nuts – Different varieties of nuts are mixed together in order to form mixed nuts. These are generally used in any kind of parties and events.
ii. Rocks on the sand of sea beaches - The sand beds contain a number of pebbles and rocks on it that can be easily separated from one another.
iii. Soil – Soil is a mixture of clay, mud, dead plants and decays, stones, earthworms and other living materials.
iv. Salad – Various types of fresh vegetables and other food substances like cucumber, onion, tomatoes, lettuce, cheese, salt and pepper, broccoli and so on are cut into pieces and are served to the customers as a mixture of vegetables.
If mixture of liquid substances are considered –
Generally the mixture of two liquid substances is termed as emulsion. The different examples are-
i. Mixture of oil and water.
ii. Mixture of oil, water and colours.
iii. Mixture of kerosene and water.
i. Fog and mists – Tiny water droplets float in the air and forms a vapour like coat everywhere.
ii. Fire smoke – Smokes from the fire is an example of heterogeneous such mixture where the carbon dioxide formed by the oxidation process combines with the air that surrounds the flame.
iii. Smog – It is the mixture of various air particles and the pollutants suspended in the air.
iv. Perfume and Cologne – Mixture of different tiny droplets of scent chemicals that drifts like a gas.
Mixed combinations form a number of heterogeneous mixtures. The examples are –
i. Vegetable soups – It is a very common heterogeneous mixture formed with liquid and solid substances. The base of the soup is the water and the vegetables and protein parts are added to it.
ii. Bowl of Cereals – Cereals is mixed with milk and some amount of salt and sugar for the taste.
iii. Another example of a multiphase mixture is carbonated drinks where Carbon dioxide is mixed with flavoured water.
iv. Concrete- It is a heterogeneous mixture of cement and water.
v. Mixture of salt and pepper.
vi. Ice cubes on any kind of drinks.
vii. Orange juice is also a heterogeneous mixture. It contains pulp as well as liquid and the composition is not uniform throughout.
viii.Human blood is also a heterogeneous mixture as it contains a number of different minute substances in it and the composition is different for different people.