Matter Around Us

Samacheer Book Back Questions And Answers For Science Standard 9 “Matter Around Us“

I. Choose the correct answer:
1. The separation of denser particles from lighter particles done by rotation at high speed is called _____.
(a) Filtration
(b) sedimentation
(c) decantation
(d) centrifugation

2. Among the following _____ is a mixture.
(a) Common Salt
(b) Juice
(c) Carbon dioxide
(d) Pure Silver

3. When we mix a drop of ink in water we get a _____.
(a) Heterogeneous Mixture
(b) Compound
(c) Homogeneous Mixture
(d) Suspension

4. _____ is essential to perform separation by solvent extraction method.
(a) Separating funnel
(b) filter paper
(c) centrifuge machine
(d) sieve

5. _____ has the same properties throughout the sample.
(a) Pure substance
(b) Mixture
(c) Colloid
(d) Suspension

II. State whether true or false. If false, correct the statement:
1. Oil and water are immiscible with each other.
2. A compound cannot be broken into simpler substances chemically.
3. Liquid – liquid colloids are called gel.
4. Buttermilk is an example of heterogeneous mixture.
5. Aspirin is composed of 60% Carbon, 4.5% Hydrogen and 35.5% Oxygen by mass. Aspirin is a mixture.

Answers:
1. True
2. False (A compound can be broken into simpler substances chemically)
3. False (Liquid – Solid colloids are called gel)
4. True
5. False (It is Compound. It is because the components are combined in a fixed ratio by mass)

III. Match the following:
1. Element            A. Settles down on standing
2. Compound       B. Impure substance
3. Colloid              C. Made up of molecules
4. Suspension       D. Pure substance
5. Mixture             E. Made up of atoms

Answers:
1. D
2. E
3. C
4. A
5. B

IV. Fill in the blanks:
1. A _____ mixture has no distinguishable boundary between its components.
2. An example of a substance that sublimes is _____.
3. Alcohol can be separated from water by _____.
4. In petroleum refining, the method of separation used is _____.
5. Chromatography is based on the principle of _____.

Answers:
1. Homogeneous
2. Dry ice / Solid CO^₂ / Camphor
3. Fractional distillation
4. Fractional distillation
5. different solubilities

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