Matter and Its Composition (Living Science Chemistry)
Exercises
A. Tick the most appropriate answer.
1. The amount of matter contained in an object is known as its.
a. shape. [ ]
b. size. [ ]
c. volume. [ ]
d. mass. [✓]
2. The amount of space occupied by matter is called its.
a. shape. [ ]
b. size. [ ]
c. mass. [ ]
d. volume. [✓]
3. The smallest particle of matter is called.
a. atom. [✓]
b. molecule. [ ]
c. element. [ ]
d. compound. [ ]
4. The intermolecular force is the strongest in.
a. solids. [✓]
b. gases. [ ]
c. liquids. [ ]
d. both b and c. [ ]
5. The intermolecular force is the weakest in.
a. solids. [ ]
b. liquids. [ ]
c. gases. [✓]
d. both b and c. [ ]
6. The intermolecular space is the least in.
a. solids. [✓]
b. liquids. [ ]
c. gases. [ ]
d. none of these. [ ]
B. Fill in the blanks.
1. Everything that occupies space and has mass is called matter.
2. A molecule is the smallest particle of a substance, which can exist independently.
3. The atoms of an element combine to give a molecule, which is called a molecule of the element.
4. The atoms of different elements combine to give a molecule, which is called a molecule of a compound.
5. The molecules of a substance are held together together by an intermolecular force of attraction.
6. The space between molecules of matter is known as intermolecular space.
7. Liquids have the property of being able to flow.
C. Write true or false. Correct the false statements.
1. Matter makes up all the materials around you. [T]
2. More the amount of matter in an object, less is its mass. [F]
= More the amount of matter in an object, greater is its mass.
3. Air does not occupy space. [F]
= Air occupies space.
4. Molecules are formed by the combination of atoms. [T]
5. The state of matter depends on the intermolecular force and the intermolecular space between the molecules of the matter. [T]
6. The intermolecular force of attraction is the strongest in gases. [F]
= The intermolecular force of attraction is the strongest in solids.
D. Name the following.
1. The amount (quantity) of matter contained in an object.
= Mass.
2. The amount of space occupied by matter.
= Volume.
3. The building blocks of all matter.
= Atoms.
4. The force of attraction between the molecules of a substance.
= Intermolecular force.
5. The space between molecules of a substance.
= Intermolecular space.
E. Answer the following
1. What is mass?
= The amount (quantity) of matter contained in an object in known as its mass.
2. What is volume?
= The amount of space occupied by matter is called its volume.
3. Define atoms.
= Matter is made up of very tiny particles called atoms.
4. Define molecules.
= The atoms of an element combine to give a molecule, which is called a molecule of the element.
5. What is intermolecular force of attraction?
= The molecules of a substance are held together by a force of attraction between them. This is known as the intermolecular force of attraction.
6. What is intermolecular space?
= Depending upon the strength of intermolecular force, there are spaces between the molecules of a substance. The space between molecules is known as intermolecular space.
F. Answer the following in detail.
1. Matter has mass. Explain with an example.
= Aim : To show that matter has mass.
Materials required : A spring balance, cotton thread, a small empty can, water, pebbles or sand.
Procedure :
1. Suspend a spring balance from a hook. The reading of the pointer should read 0 (zero).
2. Take an empty can and tie a piece of strong cotton thread to it to make a suspension loop. Now suspend the can form the hook of the spring balance.
3. Note the reading of the pointer.
4. Repeat the experiment taking sand or pebbles in the can.
6. Note the reading of the pointer each time.
Conclusion :The difference between the final and the initial readings of the pointer gives the weight of the things put in the can. Thus, from the activity, we conclude that matter has mass.
2. Matter occupies space. Explain with an example.
= Aim : To show that matter occupies space.
Materials required : A glass tumbler, water, a stone, a piece of thread, a glass bowl.
Procedure :
1. Take a glass tumbler and place it in a bowl. Pour water gently into the tumbler so that it is completely filled.
2. Now take a small stone. Tie it with a piece of thread and lower this stone gently into the tumbler.
3. Remove the stone from the glass tumbler. See the level of the water in the tumbler. Now pour the water collected in the bowl into the tumbler.
Observation :
1. When the stone is lowered into the glass tumbler filled completely with water, some water overflows from the glass tumbler and collects in the bowl.
2. When the stone is removed from the glass tumbler and the water collected in the bowl is poured back into the tumbler, the water fills the glass tumbler up to the brim again.
Conclusion : The stone occupies space and hence pushes the water out of the tumbler. Water is matter too and also occupies space. This is observed when it fills the tumbler up to its brim. Thus, from this activity, we conclude that matter occupies space.
3. Differentiate between a molecule of an element and a molecule of a compound.
= The atoms of an element combine to give a molecule, which is called a molecule of the element. For example, two atoms of hydrogen combine to give a molecule of hydrogen. The atoms of different elements combine to give a molecule, which is called a molecule of a compound. For example, two atoms of hydrogen and one atom of oxygen combine to form water.
4. Compare solids, liquids, and gases in terms of their intermolecular force of attraction and intermolecular space.
=
|
Solid |
Liquid |
Gas |
|---|---|---|
|
The intermolecular force is the strongest in solids. |
The intermolecular force of attraction in liquids is not so strong as
in solids. |
The intermolecular force of attraction is the weakest in gases. |
|
The intermolecular space between the molecules in solids is
practically absent and the molecules are closely packed together. |
The intermolecular space between the molecules in liquids is more
than that in solids and the molecules are less closely packed. |
The intermolecular space between molecules in gases is the largest in
comparison to liquids and solids. |
Think and answer
1. Light and sound are not matter. Why?
= Light and sound are not matter because they do not have mass and volume. They are a wave.
2. The molecules in solids hardly move about; they only vibrate slightly. Why?
= The molecules in solids hardly move about; they only vibrate slightly because the inter molecular force is the strongest in solids. So, the intermolecular space between the molecules in solids is practically absent and the molecules are closely packed together.
3. Liquids have the property of being able to flow. Why?
= The intermolecular space between the molecules in liquids is more than that in solids and the molecules are less closely packed. But, the intermolecular space in liquids is less than that in gases. The molecules in a liquid can move from one position to another within the liquid. That is why liquids have the property of being able to flow.
4. The molecules of gases are very far apart and completely free to move about in the whole space available to them. Why?
= The molecules of gases are very far apart and completely free to move about in the whole space available to them. Because the intermolecular force of attraction is the weakest in gases. So, the intermolecular space between molecules in gases is the largest in comparison to liquids and solids.