Friday, 19 April 2013

Classify the following as chemical or physical changes:

1. Classify the following as chemical or physical changes:
(i)cutting of trees,
(ii) melting of butter in a pan,
(iii) rusting of almirah,
(iv) boiling of water to form steam
(v) passing of electric current, through water and the water breaking down into hydrogen and oxygen gases,
(vi) dissolving common salt in water,
(vii) making a fruit salad with raw fruits, and
(viii) burning of paper and wood.
Answer:
(i) Cutting of trees is a physical change.
(ii) melting of butter in a pan is a physical change.
(iii)  rusting of almirah is a chemical change.
(iv) boiling of water to form steam is a physical change.
(v) passing of electric current, through water and the water breaking down into hydrogen and oxygen gases is a chemical change.
(vi) dissolving common salt in water is a physical change.
(vii) making a fruit salad with raw fruits is a physical change.
(viii) burning of paper and wood is a chemical change.

14 comments:

  1. how is melting butter a physical change?

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    Replies
    1. You are only changing the state of matter the butter is in, not the chemical properties of the butter.

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  2. how is making a salad with raw fruits a physical change

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    Replies
    1. It is chemical change because a syrup like substance is formed

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  3. how is making a salad with raw fruits a physical change

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    Replies
    1. Making salad with raw fruits is a physical change as there is no change in the chemical properties of the fruits

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  4. Cutting of trees is a chemical change because it produces a chain of chemical reactions

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  5. Cutting of trees is a chemical change because it produces a chain of chemical reactions

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    Replies
    1. Cutting of trees is not a physical change since after cutting the tree , the pieces of the tree are wood only!!
      It doesn't change it's properties and energy?!

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  6. How is cutting of trees physical change...it is irreversible?

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  7. How is rushing of almirah is chemical change it's physical change bcuz in these fire is nthg has change know

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  8. Rusting is chemical change and anything rusted can't brought to new price of iron we can only paint it

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  9. How is cutting of fruit for making salad a physical change?It can be chemical also because we cannot get the fruit in its original form because it reacts with oxygen and turns changes the colour to black.

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