MEDIUM
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What is a chemical change? Give an example.

Important Questions on Changes Around Us

MEDIUM
Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes

The number of endothermic process/es from the following is _______.

A. I2( g)→2I(g)

B. HCl(g)→H(g)+Cl(g)

C. H2O(l)→H2O(g)

D. C(s)+O2( g)→CO2( g)

E. Dissolution of ammonium chloride in water

EASY
Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
What happens to an apple if it is cut and left in the open air? What type of change is this?
EASY
Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
When a candle is lit, the wax melts. Identify it is a physical or chemical change.
EASY
Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
Differentiate between reversible and irreversible changes.
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Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
Give two examples each to explain the difference between changes that can be reversed and those that cannot be reversed.
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Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
When wood is kept in contact with water for a long time, it rots. Identify it is a physical or chemical change.
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Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
When a piece of coal is burnt, it turns to ash. Identify it is a Physical change or Chemical change.
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Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
Following are few examples of changes: 
(a) The spilling of water from a bucket
(b) The burning of a candle
(c) The breaking of a glass bottle
(d) The digestion of food
(e) The melting of an ice cube
Which of the changes listed above can be reversed?
 
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Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
When the sun shines on a puddle of water, the water evaporates. Identify it is a physical change or chemical change.
MEDIUM
Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
Which of the following is an example of a reversible change?
EASY
Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes

Can you get back the matchstick from the ash left after it is burnt? Why or why not?

HARD
Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
Seema bought a new skirt for school. When she came home, she realised that it was too long, so she asked her mother to hem it. What kind of change is this?
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Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
Why cannot permanent change be reversed? When milk is turned into curd, its taste changes. Why? Can we change the curd back into milk?
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Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
 When a whisked egg is heated, it scrambles. Identify it is a physical or chemical change.
EASY
Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
What do you understand by a reversible change? Give an example.
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Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
Which of the following is an example of irreversible change?
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Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
Is converting wood into sawdust a reversible change? Give a reason in support of your answer.
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Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
Select the material that undergoes the change.
Boiling an egg.
EASY
Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes

Mention if the change is reversible change or irreversible change. 

Making a mistake while knitting a sweater is a _____.

MEDIUM
Science>Chemistry>Changes Around Us>Reversible and Irreversible Changes
When jelly cubes are heated, they melt. Identify it is a physical or chemical change.