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Q 1.
Burning of candle is a?
Ans.
Both physical and chemical changes take place.
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Q 2.
When a metal rim is fitted on wood it is first?
Ans.
Expanded than contracted.
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Q 3.
When the iron blade is fixed to the wooden handle it is fitted by?
Ans.
Heating and cooling.
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Q 4.
Salt is obtained from sea water by?
Ans.
Evaporation.
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Q 5.
The process where,water changes into vapors after heating is called?
Ans.
Evaporation.
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Q 6.
When water is mixed with plaster of Paris it becomes?
Ans.
Very hard.
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Q 7.
Natureof physical changes?
Ans.
They are temporary and are reversed.
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Q 8.
What changes does physical change involve?
Ans.
Absorption aur releases in energy.
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Q 9.
What changes does chemical change involve?
Ans.
Change of state as well as composition.
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Q 10.
Name the example of periodic change?
Ans.
Clock pendulum.
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Q 11.
What do you mean by chemical changes?
Ans.
A process that transforms one or more objects into one or more new different objects.
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Q 12.
What do you mean by physical change?
Ans.
When object or substance undergo a change that does not change its chemical composition.
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Q 13.
What are the examples of physical changes?
Ans.
Melting an ice cube.
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Q 14.
What happened when both physical and chemical changes take place?
Ans.
Energy is either absorbed aur released.
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Q 15.
What are the examples of undesirable changes?
Ans.
Earthquake
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Q 16.
Examples of irreversible changes?
Ans.
Heating,Burning and mixing and pondering.
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Q 17.
What are the properties of metals?
Ans.
1.Metal expand on heating.2.
Metal contract on cooling. |
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Q 18.
All changes are reversable in nature?
Ans.
No
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Q 19.
Examples of Reversed changes?
Ans.
1. A Ballon changes its shapes and size on blowing air into it.2.
Dissolving sugar in water |