separation of substances -post 6

CLASS 6  

 CH- SEPARATION OF SUBSTANCES -  BLOG 6

 

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 At the end of the  blog lesson you will be able to

1. Evaluate the different methods of separation of soluble solids from liquids.
2. Describe Evaporation and Condensation processes as separation methods.
...................................................................................................................Important Note: The text in green color is to be written in your notebook. 

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Today, we will discuss methods to separate:

3. SOLUBLE SOLIDS IN LIQUIDS are separated by SIMPLE CHEMICAL METHODS.

Solids like sugar, salt etc dissolved in liquids are separated by 

 Evaporation:

 The process by which any liquid is converted into its vapour form.

E.g. Salt is separated from sea water by this method.

The picture below shows SALT PANS or Lagoons.  This is a fairly common site in coastal areas.

But don't you think this will be a long and boring method. 

 Is there a way to hasten the process of evaporation?

⇨Yes. The process can be faster if more heat is provided.

Condensation:

 The process by which a vapour  is converted into liquid form by cooling is called condensation.

Click on the link below and watch the video for a demonstration of the two processes:

https://www.youtube.com/watch?v=zNnytH2NsDo

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 Click on the link below to learn the difference between Evaporation and Boiling

 https://www.youtube.com/watch?v=hSLZJ-P3VBU

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 WRITTEN WORK - Do the question given below in your notebook

Q) Differentiate between Evaportion and Boiling.

 A)  i)Evaporation takes place at all temperatures.

Boiling takes place at the boiling point of the liquid.

ii) Evaporation takes place from  the surface of the liquid. 

Boiling takes  place throughout the liquid.

iii) Evaporation is a slow process.

Boiling is a rapid process.

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We will discuss the process through an activity tomorrow.

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