1-What is matter? give example.
Ans:- Any thing that has mass and occupies space is called matter.
Ans:- Any thing that has mass and occupies space is called matter.
Ex:- air, water, wood etc.
2-How many types of matter?
Ans:- There are three types of matter.
1- solid
2- liquid
3- gas
3-What is atom?
Ans:- The smallest unit of matter that cannot be divided further into smaller units is called atom.
Ans:- A substance that is made up of only one kind of atoms is called an element. An element can not be broken down into simpler substances by any physical or chemical means. Scientists have discovered 118 elements on earth.
Ex:-
Name of Symbol of atomic no of
Hydrogen H 1 1
Helium He 2 2
Lithium Li 3 3
Beryllium Be 4 4
Boron B 5 5
Carbon C 6 6
Nitrogen N 7 7
Oxygen O 8 8
Fluorine F 9 9
Neon Ne 10 10
Sodium Na 11 11
Magnesium Mg 12 12
Aluminum Al 13 13
Silicon Si 14 14
Phosphorus P 15 15
Sulfur S 16 16
Chlorine Cl 17 17
Argon Ar 18 18
Potassium K 19 19
Calcium Ca 20 20
5-What is molecule?
Ans:- Molecule is a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction
Ex:-
Molecule of Hydrogen – H2 (It is made up of two atoms of Hydrogen )
Molecule of oxygen – O2 (It is made up of two atoms of Oxygen )
Molecule of water – H2O ( It is made up of two atoms of Hydrogen and one atom of Oxygen )
6-What is Compound? Give some example.
Ans:- Compound is a pure substance made up of two or more elements combined in a fixed ratio.
Ex:- water – H2O , Carbon dioxide – CO2 , Sodium oxide – Na2O
Ans:- A substance that has definite shape and definite volume is called solid.
Ex:- ice, bricks, stone, wood, iron etc.
8-Why solids are hard and has definite shape and volume?
Ans:- Solids are hard and has definite shape and volume because the molecules of solids are very closely packed and has great molecular force.
9-What is liquid? give example.
Ans:- A substance that has definite volume but no definite shape is called liquid.
Ex:- water, milk, oil, honey, juice etc.
10-Why does liquid flow?
Ans:- Liquid flows because the molecules of liquid are loosely packed and has less molecular force.
Ans:- A substance that has no definite volume and shape is called gas.
Ex:- air, water vapour, etc
12-Why do gases have neither definite shape nor definite volume?
Ans:- Gases have neither definite shape nor definite volume because
the molecules of gases are very loosely packed and has very less molecular force.
13-What are soluble substances?
Ans:- Those solid substances that dissolve in water are called soluble substances.
14-What are insoluble substances?
Ans:- Those solid substances that do not dissolve in water are called insoluble substances.
Ex:- sand, wood, chalk etc
15-What are solute?
Ans:- A substance that is dissolved in a solution is called a solute.
Ex- salt, sugar, alum etc.
16-What are solvent?
Ans:- The liquid which allows the solute to dissolve in it, so as to form a solution is called solvent.
Ex- milk, water
17-What are solution?
Ans:- A solution is a homogeneous mixture of two or more components in which the particles size is smaller than 1nm.
Ex- solution of sugar and water, solution of salt and water
18-Write two factors that increase the solubility?
Ans:- Solubility is increased by stirring a solution.
Solubility is increased by increasing temperature.
19-What are miscible liquids?
Ans:- liquids which mix together in all proportions and form a single layer are called miscible liquids.
Ex:- water and milk are miscible
20-What are immiscible liquids?
Ans:- liquids which do not mix with each other and form separate layers are called immiscible liquids.
Ex:- oil and water are immiscible
21-Why is water a universal solvent?
Ans:- Water is called a universal solvent because it dissolves more substance than any other liquid.
Ans:- The changes in which only physical property of a substance changes and no new substance is formed is called physical change.
Example:-
melting of butter
melting of ice-cream
melting of wax
shredding of paper
shredding of clothes
chopping wood
23-What are chemical changes?
Ans:- The changes in which new substances with different properties are formed are called chemical changes
Example:-
burning wood
souring milk
cooking rice
baking cake
2-How many types of matter?
Ans:- There are three types of matter.
1- solid
2- liquid
3- gas
3-What is atom?
Ans:- The smallest unit of matter that cannot be divided further into smaller units is called atom.
Ans:- A substance that is made up of only one kind of atoms is called an element. An element can not be broken down into simpler substances by any physical or chemical means. Scientists have discovered 118 elements on earth.
Ex:-
Name of Symbol of atomic no of
Hydrogen H 1 1
Helium He 2 2
Lithium Li 3 3
Beryllium Be 4 4
Boron B 5 5
Carbon C 6 6
Nitrogen N 7 7
Oxygen O 8 8
Fluorine F 9 9
Neon Ne 10 10
Sodium Na 11 11
Magnesium Mg 12 12
Aluminum Al 13 13
Silicon Si 14 14
Phosphorus P 15 15
Sulfur S 16 16
Chlorine Cl 17 17
Argon Ar 18 18
Potassium K 19 19
Calcium Ca 20 20
5-What is molecule?
Ans:- Molecule is a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction
Ex:-
Molecule of Hydrogen – H2 (It is made up of two atoms of Hydrogen )
Molecule of oxygen – O2 (It is made up of two atoms of Oxygen )
Molecule of water – H2O ( It is made up of two atoms of Hydrogen and one atom of Oxygen )
6-What is Compound? Give some example.
Ans:- Compound is a pure substance made up of two or more elements combined in a fixed ratio.
Ex:- water – H2O , Carbon dioxide – CO2 , Sodium oxide – Na2O
Ans:- A substance that has definite shape and definite volume is called solid.
Ex:- ice, bricks, stone, wood, iron etc.
8-Why solids are hard and has definite shape and volume?
Ans:- Solids are hard and has definite shape and volume because the molecules of solids are very closely packed and has great molecular force.
9-What is liquid? give example.
Ans:- A substance that has definite volume but no definite shape is called liquid.
Ex:- water, milk, oil, honey, juice etc.
10-Why does liquid flow?
Ans:- Liquid flows because the molecules of liquid are loosely packed and has less molecular force.
Ans:- A substance that has no definite volume and shape is called gas.
Ex:- air, water vapour, etc
12-Why do gases have neither definite shape nor definite volume?
Ans:- Gases have neither definite shape nor definite volume because
the molecules of gases are very loosely packed and has very less molecular force.
13-What are soluble substances?
Ans:- Those solid substances that dissolve in water are called soluble substances.
14-What are insoluble substances?
Ans:- Those solid substances that do not dissolve in water are called insoluble substances.
Ex:- sand, wood, chalk etc
15-What are solute?
Ans:- A substance that is dissolved in a solution is called a solute.
Ex- salt, sugar, alum etc.
16-What are solvent?
Ans:- The liquid which allows the solute to dissolve in it, so as to form a solution is called solvent.
Ex- milk, water
17-What are solution?
Ans:- A solution is a homogeneous mixture of two or more components in which the particles size is smaller than 1nm.
Ex- solution of sugar and water, solution of salt and water
18-Write two factors that increase the solubility?
Ans:- Solubility is increased by stirring a solution.
Solubility is increased by increasing temperature.
19-What are miscible liquids?
Ans:- liquids which mix together in all proportions and form a single layer are called miscible liquids.
Ex:- water and milk are miscible
20-What are immiscible liquids?
Ans:- liquids which do not mix with each other and form separate layers are called immiscible liquids.
Ex:- oil and water are immiscible
21-Why is water a universal solvent?
Ans:- Water is called a universal solvent because it dissolves more substance than any other liquid.
Ans:- The changes in which only physical property of a substance changes and no new substance is formed is called physical change.
Example:-
melting of butter
melting of ice-cream
melting of wax
shredding of paper
shredding of clothes
chopping wood
23-What are chemical changes?
Ans:- The changes in which new substances with different properties are formed are called chemical changes
Example:-
burning wood
souring milk
cooking rice
baking cake
rusting of iron
No comments:
Post a Comment
If you have any doubt, please let me know