One Mark Questions Answers

CHEMISTRY

MATTER AROUND US

TEXT BOOK EXERCISES

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

[Answer: (d) centrifugation]

2. Among the following _――― is a mixture.

(a) Common Salt

(b) Juice

(c) Carbon dioxide

(d) Pure Silver

[Answer: (b) Juice]

3. When we mix a drop of ink in water we get a _――― .

(a) Heterogeneous Mixture

(b) Compound

(c) Homogeneous Mixture

(d) Suspension

[Answer: (c) Homogeneous Mixture]

4. _――― is essential to perform separation by solvent extraction method.

(a) Separating funnel

(b) filter paper

(c) centrifuge machine

(d) sieve

[Answer: (a) Separating funnel]

5. _――― has the same properties throughout the sample.

(a) Pure substance

(b) Mixture

(c) Colloid

(d) Suspension

[Answer: (a) Pure substance]

II. State whether true or false. If false, correct the statement.

1. Oil and water are immiscible with each other.

Answer: True.

2. A compound cannot be broken into simpler substances chemically.

Answer: False.

Correct statement: A compound can be broken into simpler substances chemically.

3. Liquid - liquid colloids are called gel.

Answer: False.

Correct statement : Liquid - Solid colloids are called gel.

4. Buttermilk is an example of heterogeneous mixture.

Answer: True.

5. Aspirin is composed of 60% Carbon, 4.5% Hydrogen and 35.5% Oxygen by mass.

Aspirin is a mixture.

Answer: False.

Correct statement: It is Compound. It is because the components are combined in a fixed ratio by mass.

III. Match the following :

 A - B

Element -Settles down on standing

Compound - Impure substance

Colloid - Made up of molecules

Suspension - Pure substance

Mixture - Made up of atoms

Answer:

A - B

Element - Pure substance

Compound - Made up of atoms

Colloid - Made up of molecules

Suspension - Settles down on standing

Mixture - Impure substance

IV. Fill in the blanks :

1. A Homogeneous mixture has no distinguishable boundary between its components.

2. An example of a substance that sublimes is Dry ice / Solid CO₂ / Camphor .

3. Alcohol can be separated from water by Fractional distillation.

4. In petroleum refining, the method of separation used is Fractional distillation.

5. Chromatography is based on the principle of different solubilities.