6 Science Chapter 5 Separation Of Substances

Chapter Notes and Summary
• A substance that is obtained by mixing more than one kind of particles is called a mixture.
• A mixture is made of two or more pure substances mixed together.
Mixtures are everywhere around us. Examples :
Air – Mixture of different gases.
Face cream – Mixture of oil, water and chemicals.
Aerated drink – Mixture of water, sugar and carbon dioxide.
• different substances present in a mixture are called its components.
• Mixtures do not have a fixed melting and boiling point.
• A mixture in which all of its components are evenly distributed throughout mixture is known as homogeneous mixture. e.g., mixture of salt and water.
• A mixture in which its components are not distributed evenly throughout mixture is known as heterogeneous mixture. e.g., mixture of oil and water.
• Pure metals are separated from their natural mixed forms called ores.
• Separation of a mixture means removal of one substances from a mixture of two or more substances.
• Hand-picking is a method of separation of solids which involves picking out substances by hand and separating them from others.
• Threshing is process of separating grains from harvested stalks of crops.
• Winnowing is used for separating grains from husk.
• Sieving is used for separating components of a mixture on basis of their size of particles.
• substances which are attracted to a magnet are known as magnetic substances.
• process of settling down of heavier insoluble components in a mixture is known as sedimentation.
• clear liquid that remains above sediments is called supernatant.
• process of pouring out supernatant slowly to another container is called decantation.
• process of separating insoluble components from a mixture using a filter paper cloth is called filtration.
• process of adding of alum in muddy water which loads mud particles and speeds up sedimentation, is known as loading.
• Evaporation is a method used to separate a dissolved solid component from a solution by heating.
• Distillation is a method of obtaining a pure liquid from a solution by heating at a certain temperature.
• A solute is substance that is dissolved in solvent to form solution.
• A solvent is a substance in which other materials dissolve.
• ability of a substance to dissolve in water to form a solution is known as solubility.
• Water is capable of dissolving a variety of different substances. So, it is known as ‘universal solvent’.

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