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Class 7
Science
Physical and Chemical Changes
the gas we use in the kitchen is called liquified...

Question:
The gas we use in the kitchen is called liquified petroleum gas (LPG). In the cylinder it exist as a liquid. When it comes out from the cylinder it
becomes a gas (Change – A) then it burns (Change – B). The following statements pertain to these changes. Choose the correct one.

(i) Process – A is a chemical change.
(ii) Process – B is a chemical change.
(iii) Both processes A and B are chemical changes.
(iv) None of these processes is a chemical change.

Answer:

(ii) Process - B is a chemical change

LPG is present in liquid form in the cylinder and when it comes in the contact of environment it converts into gaseous form which is a physical change. But When it burns, it converts in the from of heat and light, then this is a chemical change; this cannot be reversed.

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