Wednesday, 12 September 2018

CBSE Class 9 - Chemistry - Matter in Surroundings - Short Questions Answers (#cbsenotes)(#eduvictors)

Chemistry - Matter in Surroundings

CBSE Class 9 - Chemistry - Matter in Surroundings - Short Questions Answers (#cbsenotes)(#eduvictors)

Short Questions Answers

Q1: Define matter.

Answer: Anything that has mass and occupies space is called matter.

Q2: Write your observation and conclusion for the following:
(a) When few marbles are put in a glass half filled with water.
(b) Ice is kept at room temperature.

Answer:
(a) Take some marbles and put them into the water of glass tumbler one by one. After some time you will notice that the water level crosses the mark and rises. This is because the marbles occupy space. Again weigh the glass with the marbles. You will find that the second mass is greater than the first one. This proves that marbles have mass.



CBSE Class 9 - Chemistry - Matter in Surroundings - Short Questions Answers (#cbsenotes)(#eduvictors)


It shows that matter has mass and occupies space.

(b) Ice, when kept at room temperature again, changes back into liquid water.


Q3: State three main characteristics of the particles of matter.

Answer:
Characteristics of Matter
1. The matter is made up of very tiny particles. It can neither be created nor destroyed.
2. Particles are continuously moving.
3. Particles of matter have space between them.
4. Particles of matter attract each other.


Q4: Define :
(a) Solid
(b) Liquid
(c) Gas

Answer: Giving two examples of each type.
(a) Solid: A solid is that state of matter which has a fixed shape, mass and volume. It suffers very small changes in volume by changing the temperature. It cannot be compressed,
e.g. – Sand, Wood, Copper, Ice, etc.

(b) Liquid: It has a definite mass and volume but lacks a shape of its own. It takes up the shape of the containing vessels. It can be compressed to an extent,
e.g. – Milk, water, ink, etc.

(c) Gas: It is a state of matter which has only definite mass but no definite shape and volume. It takes up the shape of the container
e.g. – Carbon dioxide, oxygen, etc.


Q5: Why are liquids and gases called as fluids.

Answer: The particles are free to move in any direction i.e. they can flow because all substances that can flow are called fluids. Liquids and gases are fluids.


Q6: (a) Define interconversion of states of matter.
(b) Why do solids, liquids and gases differ in their physical state?
(c) Under what conditions do solids, liquids and gases change their state.

Answer:
(a) The process by which matter changes from one state to another and back to original state, without any change in its chemical composition.

(b) Intermolecular force of attraction. Intermolecular spaces are two important properties of matter that account for the different states of matter.

(c) Matter can change from one state to another on changing temperature and pressure.


Q7: Give reasons :
(a) When a stone is dipped in a glass containing some water the level of water rises but when a spoon of sugar is added to it and stirred, the water level does not rise?

(b) A drop of ink added to water in a glass turns whole water blue.

Answer:
(a) Take half a glass of water. Dip a spoon in it. What do you observe? The water level rises, indicating that spoon occupies space.

Now remove the spoon, water comes down to its original level. Now add a spoon of sugar to it and stir well. The sugar disappears but the level of water in the glass does not rise, that means the volume of water has not increased.

The sugar particles being smaller get adjusted between the water molecules. This shows that there is intermolecular space in the water.

(b) This is because the water, as well as the ink particles (molecules), are in continuous random motion. Due to motion, the blue coloured particles of the ink spread all over and give a blue colour to the water.


Q8: Fill in the blanks :
(a) Air is a matter because it has _______, _________ and ________ and it can be compressed.

(b) The molecules are made up of _________.

(c) The quantity of matter in an object is called its _______.

(d) The state of matter with a definite volume and definite shape is called _______.

(e) The substances which can flow are called _______.


Answer:
(a) weight, mass and space
(b) atoms
(c) mass
(d) solid
(e) fluids


Q9: Name the terms for the following :
(a) The change of a solid into a liquid.
(b) The force of attraction between the molecules of matter.
(c) The particles of matter which may or may not have an independent existence.
(d) The process due to which a solid directly changes into its vapours.
(e) The change of vapour into a liquid.

Answer:
(a) Melting.
(b) Intermolecular force of attraction.
(c) Solid.
(d) Sublimation.
(e) Condensation.


Q10: Define:
(a) Intermolecular force of attraction.
(b) Intermolecular space.


Answer:
(a) The molecules of matter are always in motion and attract each other with a force called the intermolecular force of attraction due to which they are held together.

(b) The molecules can move only when there are gaps or space between them, this space is called intermolecular space.


☛See also:
Ch 1 - Matter in Our Surroundings (Q & A)
Ch 1 - Matter in our Surroundings (Questions asked in CBSE papers - Unsolved)
Ch1 - Matter in our Surroundings (Unit Objective Test)
Ch1 - Matter in Our Surroundings (MCQs-1)
Ch1 - Matter In Our Surroundings (Question Bank)
Ch1 - Matter In Our Surroundings (Unit Test Paper)
Ch1 - Matter in Our Surroundings (MCQs-2)
Ch1 - Matter in Our Surroundings (Reasoning Questions)
Ch1 - Matter in Our Surroundings (Revision Assignment)
Ch1 - Matter in Our Surroundings (Revision Assignment-2)

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