Experiments in Preparation of Mixtures

In chemistry, there are a lot of basic concepts that need our attention. One such topic is mixture and compounds. The mixture falls under two categories: Heterogeneous and homogeneous. A practical understanding of chemistry is always gained by performing experiments. In this article, we will learn about what each type of mixture means and the process of preparation of mixtures in a laboratory setting.

Mixture

Mixtures are a product of the blending of two or more substances. The substances or components retain their chemical identity and properties. Also, no reaction takes place

Examples of mixtures

• A mixture of organic compounds (consisting of hydrocarbons): Crude oil
• A mixture of gases like oxygen, nitrogen, carbon dioxide neon, argon, etc.: Air mixture of salt and water: Seawater
• A mixture of coloured dyes: Ink
• A mixture of potassium, sulphur, carbon and nitrate: Gunpowder

Important properties of Mixtures

• All the components in a mixture retain their physical properties
• The mixture can be separated through experiments into its components by using some techniques, which are discussed in this article
• The substances in a mixture may be in a fixed or uniform proportion or not, they can vary in quantity
• The mixture’s composition isn’t fixed
• Energy is neither created nor developed when a mixture is formed
• The melting and boiling points of the combination are not set

Types of mixtures

There two types of mixtures are a heterogeneous mixture and a homogeneous mixture.

Heterogeneous mixtures

Heterogeneous mixtures have components that are distinguishable in a visible way when mixed. Each component in the mixture is non-uniform, in terms of proportion.

Homogenous mixtures

Homogeneous mixtures are uniform throughout. The individual components cannot be distinguished after the mixture is made. The solution is a homogenous mixture of the most common type which can have the property of a solid, liquid, or gas.

Experiments on the preparation of mixtures

Preparation of a homogenous mixture and a heterogeneous mixture.

Requirements

• Sodium chloride and sugar
• sand/chalk powder
• Water
• micro beaker
• stirring rod
• Funnel
• filter paper
• Tripod
• starch powder
• kerosene burner

Process

Preparation of mixtures (Homogeneous)

1. Take a 10 mL micro beaker and add 5 mL of water to it. Add one spoon of sodium chloride or sugar to it.
2. Stir it thoroughly and then filter it.
3. Note observations.

Are any particles settling down inside the solution in the micro beaker?

Answer: No.

Conclusion: Salt/sugar in water forms a homogenous mixture.

Preparation of mixtures (suspension)

1. Take a micro beaker and add 5 mL of water inside. Also, add one spoon of sand or chalk powder.
2. Stir it thoroughly and note observations.
3. Using filter paper, filter the solution of water and sand or chalk powder.
4. Note observations on filter paper carefully.

The solution of Sand or Chalk powder mixed with water forms a heterogeneous mixture.

Suspensions are characterised by opacity. Suspended solids can be separated from the solution using filtration.

Preparation of mixtures (colloidal solution)

1. Take a 10 mL micro beaker and add one spoon of starch powder to it. Mix it well, till a paste is formed.
2. In another micro beaker containing 5 mL of water, add the paste thus formed gradually using constant stirring.
3. Whilst performing constant stirring, heat the mixture. But remember: Do not boil.
4. Cool the mixture and then filter it.
5. Note observations on the filter paper.

In the filtrate did you observe the presence of some turbidity?

Conclusion:

In a colloidal solution, one cannot see the starch particles. In colloids, The particles are too small to be noticed with naked eyes.

Pass a  beam of light through the solution thus prepared. Now you can see that the particles are present. They only become visible by scattering a beam of light.

Colloidal solutions are translucent and form a heterogeneous mixture. Unlike a suspension, Solid particles in a colloidal solution cannot be separated from the mixture using filtration.

Enamel paint is one of the most common examples of a colloidal solution and a heterogeneous mixture.

Purpose of a mixture/ uses of a mixture

1: Mixtures can be handy when you need to blend components from different sources into a single product.

2: Mixtures enable you to dilute a pure component into a product with less substance per unit volume. For example, if you would like to rehydrate and replace electrolytes, you may combine salt with water.

Conclusion

Chemistry is all about the practical application in everyday life. To understand how things work, an understanding of the basics of chemistry is quintessential. Mixtures and examples of mixtures are everywhere, and in this article, we discussed the experiments in preparation for mixtures. Practice them in your laboratory under supervision and note observations.