Classify the following as chemical or physical changes:

  • cutting of trees,

  • melting of butter in a pan,

  • rusting of almirah,

  • boiling of water to form steam,

  • passing of electric current, through water and the water breaking down into hydrogen and  oxygen gases,

  • dissolving common salt in water,

  • making a fruit salad with raw fruits, and

  • burning of paper and wood

 

Answer

  • Cutting of trees- Physical change

(During cutting of trees no new substance is formed, hence its a physical change)

 

Cutting of trees

 

Link for the above image is given below: -

 

http://www.ehs.ufl.edu/programs/os/chainsaw/chain-saw-safety-2/

  • Melting of butter in a pan - Physical change

(It is a physical change  because it is a change of state of matter from solid to liquid

This change is temporary and can be reversed)

 

Melting of butter in a pan

 

Link of the above image is given below: -

 

https://www.dreamstime.com/butter-frying-pan-cooking-food-butter-frying-pan-cooking-food-skillet-using-oil-black-tool-margarine-inside-image136016839



  • Rusting of almirah- Chemical Change

(Rusting is a chemical reaction in which iron reacts with oxygen to form a new substance called rust(ferric oxide), hence its a chemical change)



Rusting of Iron

Link; -

https://www.blendspace.com/lessons/nLU7WkXGv2ZhDQ/chemical-reactions



  • Boiling of water to form steam - Physical Change

(It is a physical change  because it is a change of state of matter from liquid to gas.

This change is temporary and can be reversed)

 

The process of boiling and evaporation causing water to change its state from liquid to gaseous - Physical change

 

Link: - 

 

https://courses.lumenlearning.com/cheminter/chapter/boiling-point/



  • Passing of electric current, through water and the water breaking down into hydrogen and   oxygen gases - Chemical Change

 

(Passing current in water breaks it into Hydrogen and Oxygen, hence new substances are formed. Therefore, its a chemical change)

 

Passing of electricity through water to form separate bubbles of hydrogen and oxygen

 

Link: - (This image was present on brainly.in which is a platform where answers are given to the asked questions - basically it is not a typical e-learning website, so i have given the link, which contains only the image.)

 

https://hi-static.z-dn.net/files/d02/27801012c6df320fb0b1709257d95189.gif




  • Dissolving common salt in water- Physical Change

(It is a physical change because this change can be reversed to get back salt and water

This can be done by heating salt solution and water.

Water will convert into water vapour and we can get salt at the bottom of container)

 

Dissolving of common salt in water

Link: -

 

http://www.morewithmusic.org/2010/05/solute-solvent-solution.html




  • Making a fruit salad with raw fruits - Physical Change

(It is a physical change because no new substances are formed and this change can be reversed to get back different fruits)

 

Fruit salad with raw fruits

Link: -

 

https://www.vectorstock.com/royalty-free-vector/fruit-yogurt-salad-vector-1813998



  • Burning of paper and wood - Chemical Change

(It is a chemical change because when we burn paper and wood,new substances are formed like carbon and smoke. This change cannot be reversed)

 

 

Burning of wood

Link: -

 

https://www.dreamstime.com/burning-fire-campfire-firewood-logs-fire-wood-camp-fire-vector-graphics-to-design-burning-fire-campfire-firewood-logs-fire-image156467553#_





Burning of paper

Link: -

 

https://www.alamy.com/stock-photo-cartoon-illustration-of-paper-journal-running-on-fire-175528917.html






  1. Class 9
  2. Chapter 2 Class 9 - Is Matter Around Us Pure

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.