Separation Of Substances : Separation Of Substances
What is Separation? : What is Separation? Separation means removal of
substances from a mixture of
two or more substances.
1) Separating stones from rice
2) Separating tea from tea leaves
3) Churning milk to obtain butter
Why do we separate substances? : Why do we separate substances? To obtain two different, but useful components To remove non-useful components To remove impurities or harmful components To group substances of different sizes
Methods of Separation : Methods of Separation Handpicking Used for separating large sized impurities like stones and husk from rice, wheat or pulses. Threshing Used for separating grains from stalks. Machines can also be used for the process.
Slide 5 : Winnowing Sieving Used to separate heavier and lighter components of a mixture by wind or by blowing air. Example: Separation of lighter husk particles from heavier seeds of grain. Used when components of a mixture have different sizes. Example: Pebbles and stones removed from the sand.
Are there any other methods of Separation? : Are there any other methods of Separation? Sedimentation Separation of 2 components in such a way that the heavier substance settles down Heavier substance Lighter liquid
Slide 7 : Decantation Separation of 2 components that do not mix well with each other. For example separation of oil and water. While water settles down being heavier than oil, the oil forms the top layer which is then separated by Decantation
Slide 8 : Filtration Separation of solids from liquids either by using a filter paper or a strainer. For example separating tea from tea leaves using a strainer or separating mud from water using a filter paper. Filter paper Strainer
Slide 9 : Evaporation Evaporation is used when we want to get back a substance that has been dissolved.
Example: Getting salt out of salty water
The salty water is put into an evaporating basin (or any shallow dish such as a saucer). It is left in a warm place and the water evaporates leaving behind the salt crystals. Salt crystals left behind after evaporation
Slide 10 :
Can water dissolve anyamount of a substance? : Can water dissolve anyamount of a substance? Water dissolves different amounts of soluble substances in it.
A saturated solution is one in which no more of that substance can be dissolved.
More of a substance can be dissolved in a solution by heating it.
Now can you guess which method should be used to separate the following substances : Now can you guess which method should be used to separate the following substances Stones from Grain Mixture of Dry Sand with Sawdust or Powdered Dry Leaves Mixture of Pebbles and Stones Mixture of Tea and Tea Leaves