A heterogeneous mixture of insoluble particles of solute spread throughout a solvent is called suspension. For example, muddy water, slaked lime, paints etc. Sedimentation occurs in suspension as it contains solid particles sufficiently large for sedimentation which settle down under gravity.

Colloid is a heterogeneous mixture in which the particle size is in between 10 -7 cm to 10 -5 cm so, that the solute particles neither dissolve nor settle down in a solvent. For example, milk, face cream etc.

Core science chemistry>Chapter 2 - Is Matter Around Us Pure?>EXERCISE 2A>Q 1

MEDIUM

9th CBSE

IMPORTANT

Earn 100

What is a true solution? State three characteristics of a true solution.

Important Questions on Is Matter Around Us Pure?

MEDIUM

9th CBSE

IMPORTANT

Core science chemistry>Chapter 2 - Is Matter Around Us Pure?>EXERCISE 2A>Q 2

Give three differences between a colloidal solution and a suspension.

MEDIUM

9th CBSE

IMPORTANT

Core science chemistry>Chapter 2 - Is Matter Around Us Pure?>EXERCISE 2A>Q 3

What are colloidal solutions? How do they differ from true solutions?

HARD

9th CBSE

IMPORTANT

Core science chemistry>Chapter 2 - Is Matter Around Us Pure?>EXERCISE 2A>Q 5

During an experiment, the students were asked to prepare a

10 %

(Mass/Mass) solution of sugar in water. Ramesh dissolved

10

g of sugar in

100

g of water while Sarika prepared it by dissolving

10

g of sugar in water to make

100

g of the solution.
(a) Are the two solutions of the same concentration.
(b) Compare the mass

%

of the two solutions.

MEDIUM

9th CBSE

IMPORTANT

Core science chemistry>Chapter 2 - Is Matter Around Us Pure?>EXERCISE 2A>Q 6

A group of students took an old shoe box and covered it with black paper from all sides. They fixed a source of light (a torch) at one end of the box by making a hole in it and made another hole on the other side to view the light. They placed a milk sample contained in a beaker/tumbler in the box. They were amazed to see that milk taken in the tumbler was illuminated. They tried the same activity by taking a salt solution but found that light simply passed through it.
(a) Explain why the milk sample was illuminated. Name the phenomenon involved.
(b) Same results were not observed with a salt solution. Explain.
(c) Can you suggest two more solutions which would show the same effect as shown by the milk solution?

EASY

9th CBSE

IMPORTANT

Core science chemistry>Chapter 2 - Is Matter Around Us Pure?>EXERCISE 2A>Q 1

Define suspension.

EASY

9th CBSE

IMPORTANT

Core science chemistry>Chapter 2 - Is Matter Around Us Pure?>EXERCISE 2A>Q 1

Define colloid.

EASY

9th CBSE