Page 41 - ICSE Chemistry 8

EXERCISES

BE PROMPT

A. Fill in the blanks.
1. A ____________ refers to the transforma on of a substance from one form to another.
2. ______________ are the changes in which we get back the ini al substance by reversing the ac on.

3. Changes that are not desirable to us are called ________________.
4. A ____________ change is temporary and reversible.
5. There is an exchange of ___________ during a chemical change.

6. The process by which a substance is broken down by the ac on of microorganisms with the release
of heat and carbon dioxide is called _______________.

B. Iden fy the error in the given statements. Circle the incorrect word and write the correct word in
the blank.
1. Burs ng of balloon is a reversible change. ________________
2. Revolu on of the earth is a man-made change. ________________
3. Glowing of an electric bulb is a chemical change. ________________
4. Rus ng of iron is a physical change. ________________
5. Condensa on is a process by which a substance changes from the solid
state to the liquid state on hea ng. ________________
6. Fermenta on of dough is a chemical change which is man-made and
undesirable. ________________

C. Give two examples of each of the following changes.

Changes Examples
Reversible changes
Irreversible changes

Periodic changes
Non-periodic changes

Desirable changes
Undesirable changes

Slow changes

Fast changes
Natural changes

Man-made changes
Physical changes

Chemical changes

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