Lakhmir Singh & Manjit Kaur Solutions: Atoms and Molecules

 Page 1


3.	A t oms	and	Moleculers
V e r y 	 S h o r t 	 A n s w e r 	 T y p e 	 Q u e s t i o n s - P g - 1 2 8
1 . 	 Q u e s t i o n
Write the full form of IUPAC.
A n s w e r
IUPAC stands for International Union of Pure and Applied Chemistry. It is a
scientiic organization which develops nomenclature for chemical
compounds.
2 . 	 Q u e s t i o n
Name the scientist who gave:
(a) law of conservation of mass
(b) law of constant proportions.
A n s w e r
(a) Law of conservation of mass was given by Antoine Lavoisier in 1744.
According to this law, “Matter can neither be created nor destroyed in a
chemical reaction” .
(b) Law of constant proportions was given by Joseph Proust in 1799.
According to this law, “a chemical compound always contains same elements
in deinite proportion by mass and it does not depend on the source of
compound.”
3 . 	 Q u e s t i o n
Name the law of chemical combination:
(a) which was given by Lavoisier.
(b) which was given by Proust.
A n s w e r
(a) Law of conservation of mass was given by Antoine Lavoisier in 1744.
According to this law, “Matter can neither be created nor destroyed in a
chemical reaction” .
(b) Law of constant proportions was given by Joseph Proust in 1799.
According to this law, “a chemical compound always contains same elements
Page 2


3.	A t oms	and	Moleculers
V e r y 	 S h o r t 	 A n s w e r 	 T y p e 	 Q u e s t i o n s - P g - 1 2 8
1 . 	 Q u e s t i o n
Write the full form of IUPAC.
A n s w e r
IUPAC stands for International Union of Pure and Applied Chemistry. It is a
scientiic organization which develops nomenclature for chemical
compounds.
2 . 	 Q u e s t i o n
Name the scientist who gave:
(a) law of conservation of mass
(b) law of constant proportions.
A n s w e r
(a) Law of conservation of mass was given by Antoine Lavoisier in 1744.
According to this law, “Matter can neither be created nor destroyed in a
chemical reaction” .
(b) Law of constant proportions was given by Joseph Proust in 1799.
According to this law, “a chemical compound always contains same elements
in deinite proportion by mass and it does not depend on the source of
compound.”
3 . 	 Q u e s t i o n
Name the law of chemical combination:
(a) which was given by Lavoisier.
(b) which was given by Proust.
A n s w e r
(a) Law of conservation of mass was given by Antoine Lavoisier in 1744.
According to this law, “Matter can neither be created nor destroyed in a
chemical reaction” .
(b) Law of constant proportions was given by Joseph Proust in 1799.
According to this law, “a chemical compound always contains same elements
in deinite proportion by mass and it does not depend on the source of
compound.”
4 . 	 Q u e s t i o n
Name the scientist who gave atomic theory of matter.
A n s w e r
Atomic theory of matter was given by John Dalton. It was the irst complete
attempt to describe all the matter in the form of atoms and their properties.
5 . 	 Q u e s t i o n
Which postulate of Dalton’s atomic theory is the result of law of conservation
of mass given by Lavoisier?
A n s w e r
According to law of conservation of mass describes that, “Matter can neither
be created nor destroyed in a chemical reaction” . This law gives result to the
postulate of Dalton’s atomic theory which states that, “ Atoms can neither be
created and nor destroyed by physical and chemical changes.”
6 . 	 Q u e s t i o n
Which part of the Dalton’s atomic theory came from the law of constant
proportions given by Proust?
A n s w e r
According to law of constant proportions describes that, “a chemical
compound always contains same elements in deinite proportion by mass and
it does not depend on the source of compound.”
This law gives result to the postulate of Dalton’s atomic theory which states
that, “When two elements combine to form two or more than two different
compounds then the different masses of one element B which combine with
ixed mass of the other element bear a simple ratio to one another.”
7 . 	 Q u e s t i o n
Which ancient Indian philosopher suggested that all matter is composed of
very small particles? What name was given by him to these particles?
A n s w e r
Maharshi Kanada was ancient Indian scientist and sage who suggested that all
matter is composed of very small particles. He named the smallest particles
as “Parmanu” .
8 . 	 Q u e s t i o n
Name any two laws of chemical combination.
Page 3


3.	A t oms	and	Moleculers
V e r y 	 S h o r t 	 A n s w e r 	 T y p e 	 Q u e s t i o n s - P g - 1 2 8
1 . 	 Q u e s t i o n
Write the full form of IUPAC.
A n s w e r
IUPAC stands for International Union of Pure and Applied Chemistry. It is a
scientiic organization which develops nomenclature for chemical
compounds.
2 . 	 Q u e s t i o n
Name the scientist who gave:
(a) law of conservation of mass
(b) law of constant proportions.
A n s w e r
(a) Law of conservation of mass was given by Antoine Lavoisier in 1744.
According to this law, “Matter can neither be created nor destroyed in a
chemical reaction” .
(b) Law of constant proportions was given by Joseph Proust in 1799.
According to this law, “a chemical compound always contains same elements
in deinite proportion by mass and it does not depend on the source of
compound.”
3 . 	 Q u e s t i o n
Name the law of chemical combination:
(a) which was given by Lavoisier.
(b) which was given by Proust.
A n s w e r
(a) Law of conservation of mass was given by Antoine Lavoisier in 1744.
According to this law, “Matter can neither be created nor destroyed in a
chemical reaction” .
(b) Law of constant proportions was given by Joseph Proust in 1799.
According to this law, “a chemical compound always contains same elements
in deinite proportion by mass and it does not depend on the source of
compound.”
4 . 	 Q u e s t i o n
Name the scientist who gave atomic theory of matter.
A n s w e r
Atomic theory of matter was given by John Dalton. It was the irst complete
attempt to describe all the matter in the form of atoms and their properties.
5 . 	 Q u e s t i o n
Which postulate of Dalton’s atomic theory is the result of law of conservation
of mass given by Lavoisier?
A n s w e r
According to law of conservation of mass describes that, “Matter can neither
be created nor destroyed in a chemical reaction” . This law gives result to the
postulate of Dalton’s atomic theory which states that, “ Atoms can neither be
created and nor destroyed by physical and chemical changes.”
6 . 	 Q u e s t i o n
Which part of the Dalton’s atomic theory came from the law of constant
proportions given by Proust?
A n s w e r
According to law of constant proportions describes that, “a chemical
compound always contains same elements in deinite proportion by mass and
it does not depend on the source of compound.”
This law gives result to the postulate of Dalton’s atomic theory which states
that, “When two elements combine to form two or more than two different
compounds then the different masses of one element B which combine with
ixed mass of the other element bear a simple ratio to one another.”
7 . 	 Q u e s t i o n
Which ancient Indian philosopher suggested that all matter is composed of
very small particles? What name was given by him to these particles?
A n s w e r
Maharshi Kanada was ancient Indian scientist and sage who suggested that all
matter is composed of very small particles. He named the smallest particles
as “Parmanu” .
8 . 	 Q u e s t i o n
Name any two laws of chemical combination.
A n s w e r
Law of conservation of mass was given by Antoine Lavoisier in 1744.
According to this law, “Matter can neither be created nor destroyed in a
chemical reaction” .
Law of constant proportions was given by Joseph Proust in 1799. According
to this law, “a chemical compound always contains same elements in deinite
proportion by mass and it does not depend on the source of compound.”
9 . 	 Q u e s t i o n
‘If 100 grams of pure water taken from different sources is decomposed by
passing electricity, 11 grams of hydrogen and 89 grams of oxygen are always
obtained’. Which chemical law is illustrated by this statement?
A n s w e r
The above statement justiies the Law of constant proportions which was
given by Joseph Proust in 1799. According to this law, “a chemical compound
always contains same elements in deinite proportion by mass and it does not
depend on the source of compound.” This suggests that whatever be the
source of water, it will always contain 1:8 ratio of Hydrogen and oxygen
respectively.
1 0 . 	 Q u e s t i o n
‘If 100 grams of calcium carbonate (whether in the form of marble or chalk)
are decomposed completely, then 56 grams of calcium oxide and 44 grams of
carbon dioxide are obtained’. Which law of chemical combination is
illustrated by this statement?
A n s w e r
The above statement justiies the Law of constant proportions which was
given by Joseph Proust in 1799. According to this law, “a chemical compound
always contains same elements in deinite proportion by mass and it does not
depend on the source of compound.” This suggests that whatever be the
source of water, it will always contain 1:8 ratio of Hydrogen and oxygen
respectively.
1 1 . 	 Q u e s t i o n
What are the building blocks of matter?
A n s w e r
Matter is made up of indivisible particles known as Atoms. Atoms are the
building blocks of matter.
1 2 . 	 Q u e s t i o n
How is the size of an atom indicated?
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3.	A t oms	and	Moleculers
V e r y 	 S h o r t 	 A n s w e r 	 T y p e 	 Q u e s t i o n s - P g - 1 2 8
1 . 	 Q u e s t i o n
Write the full form of IUPAC.
A n s w e r
IUPAC stands for International Union of Pure and Applied Chemistry. It is a
scientiic organization which develops nomenclature for chemical
compounds.
2 . 	 Q u e s t i o n
Name the scientist who gave:
(a) law of conservation of mass
(b) law of constant proportions.
A n s w e r
(a) Law of conservation of mass was given by Antoine Lavoisier in 1744.
According to this law, “Matter can neither be created nor destroyed in a
chemical reaction” .
(b) Law of constant proportions was given by Joseph Proust in 1799.
According to this law, “a chemical compound always contains same elements
in deinite proportion by mass and it does not depend on the source of
compound.”
3 . 	 Q u e s t i o n
Name the law of chemical combination:
(a) which was given by Lavoisier.
(b) which was given by Proust.
A n s w e r
(a) Law of conservation of mass was given by Antoine Lavoisier in 1744.
According to this law, “Matter can neither be created nor destroyed in a
chemical reaction” .
(b) Law of constant proportions was given by Joseph Proust in 1799.
According to this law, “a chemical compound always contains same elements
in deinite proportion by mass and it does not depend on the source of
compound.”
4 . 	 Q u e s t i o n
Name the scientist who gave atomic theory of matter.
A n s w e r
Atomic theory of matter was given by John Dalton. It was the irst complete
attempt to describe all the matter in the form of atoms and their properties.
5 . 	 Q u e s t i o n
Which postulate of Dalton’s atomic theory is the result of law of conservation
of mass given by Lavoisier?
A n s w e r
According to law of conservation of mass describes that, “Matter can neither
be created nor destroyed in a chemical reaction” . This law gives result to the
postulate of Dalton’s atomic theory which states that, “ Atoms can neither be
created and nor destroyed by physical and chemical changes.”
6 . 	 Q u e s t i o n
Which part of the Dalton’s atomic theory came from the law of constant
proportions given by Proust?
A n s w e r
According to law of constant proportions describes that, “a chemical
compound always contains same elements in deinite proportion by mass and
it does not depend on the source of compound.”
This law gives result to the postulate of Dalton’s atomic theory which states
that, “When two elements combine to form two or more than two different
compounds then the different masses of one element B which combine with
ixed mass of the other element bear a simple ratio to one another.”
7 . 	 Q u e s t i o n
Which ancient Indian philosopher suggested that all matter is composed of
very small particles? What name was given by him to these particles?
A n s w e r
Maharshi Kanada was ancient Indian scientist and sage who suggested that all
matter is composed of very small particles. He named the smallest particles
as “Parmanu” .
8 . 	 Q u e s t i o n
Name any two laws of chemical combination.
A n s w e r
Law of conservation of mass was given by Antoine Lavoisier in 1744.
According to this law, “Matter can neither be created nor destroyed in a
chemical reaction” .
Law of constant proportions was given by Joseph Proust in 1799. According
to this law, “a chemical compound always contains same elements in deinite
proportion by mass and it does not depend on the source of compound.”
9 . 	 Q u e s t i o n
‘If 100 grams of pure water taken from different sources is decomposed by
passing electricity, 11 grams of hydrogen and 89 grams of oxygen are always
obtained’. Which chemical law is illustrated by this statement?
A n s w e r
The above statement justiies the Law of constant proportions which was
given by Joseph Proust in 1799. According to this law, “a chemical compound
always contains same elements in deinite proportion by mass and it does not
depend on the source of compound.” This suggests that whatever be the
source of water, it will always contain 1:8 ratio of Hydrogen and oxygen
respectively.
1 0 . 	 Q u e s t i o n
‘If 100 grams of calcium carbonate (whether in the form of marble or chalk)
are decomposed completely, then 56 grams of calcium oxide and 44 grams of
carbon dioxide are obtained’. Which law of chemical combination is
illustrated by this statement?
A n s w e r
The above statement justiies the Law of constant proportions which was
given by Joseph Proust in 1799. According to this law, “a chemical compound
always contains same elements in deinite proportion by mass and it does not
depend on the source of compound.” This suggests that whatever be the
source of water, it will always contain 1:8 ratio of Hydrogen and oxygen
respectively.
1 1 . 	 Q u e s t i o n
What are the building blocks of matter?
A n s w e r
Matter is made up of indivisible particles known as Atoms. Atoms are the
building blocks of matter.
1 2 . 	 Q u e s t i o n
How is the size of an atom indicated?
A n s w e r
The size of an atom is indicated by its radius which is called atomic radius
(radius of an atom). Atomic radius is measured in nanometre (nm) (1 metre =
109 nanometres or 1nm = 10_9m).
1 3 . 	 Q u e s t i o n
Name the unit in which the radius of an atom is usually expressed.
A n s w e r
Atomic radius is measured in nanometre (nm) (1 metre = 109 nanometres or
1nm = 10_9m).
1 4 . 	 Q u e s t i o n
Write the relation between nanometer and metre.
A n s w e r
A nanometer is one billionth part of metre. 1 metre = 1/109 nanometres or
1nm = 10_9m).
1 5 . 	 Q u e s t i o n
The radius of an oxygen atom is 0.073 nm. What does the symbol ‘nm’
represent?
A n s w e r
The symbol ‘nm’ represents Nanometre. A nanometer is one billionth part of
metre. 1 metre = 1/109 nanometres or 1nm = 10_9m).
1 6 . 	 Q u e s t i o n
Why is it not possible to see an atom even with the most powerful
microscope?
A n s w e r
Atoms are the building blocks of the matter. They are very small in size.
Hence Why is it not possible to see an atom even with the most powerful
microscope.
1 7 . 	 Q u e s t i o n
State whether the following statement is true or false:
The symbol of element cobalt is CO.
A n s w e r
False, the symbol of element cobalt is Co.
Page 5


3.	A t oms	and	Moleculers
V e r y 	 S h o r t 	 A n s w e r 	 T y p e 	 Q u e s t i o n s - P g - 1 2 8
1 . 	 Q u e s t i o n
Write the full form of IUPAC.
A n s w e r
IUPAC stands for International Union of Pure and Applied Chemistry. It is a
scientiic organization which develops nomenclature for chemical
compounds.
2 . 	 Q u e s t i o n
Name the scientist who gave:
(a) law of conservation of mass
(b) law of constant proportions.
A n s w e r
(a) Law of conservation of mass was given by Antoine Lavoisier in 1744.
According to this law, “Matter can neither be created nor destroyed in a
chemical reaction” .
(b) Law of constant proportions was given by Joseph Proust in 1799.
According to this law, “a chemical compound always contains same elements
in deinite proportion by mass and it does not depend on the source of
compound.”
3 . 	 Q u e s t i o n
Name the law of chemical combination:
(a) which was given by Lavoisier.
(b) which was given by Proust.
A n s w e r
(a) Law of conservation of mass was given by Antoine Lavoisier in 1744.
According to this law, “Matter can neither be created nor destroyed in a
chemical reaction” .
(b) Law of constant proportions was given by Joseph Proust in 1799.
According to this law, “a chemical compound always contains same elements
in deinite proportion by mass and it does not depend on the source of
compound.”
4 . 	 Q u e s t i o n
Name the scientist who gave atomic theory of matter.
A n s w e r
Atomic theory of matter was given by John Dalton. It was the irst complete
attempt to describe all the matter in the form of atoms and their properties.
5 . 	 Q u e s t i o n
Which postulate of Dalton’s atomic theory is the result of law of conservation
of mass given by Lavoisier?
A n s w e r
According to law of conservation of mass describes that, “Matter can neither
be created nor destroyed in a chemical reaction” . This law gives result to the
postulate of Dalton’s atomic theory which states that, “ Atoms can neither be
created and nor destroyed by physical and chemical changes.”
6 . 	 Q u e s t i o n
Which part of the Dalton’s atomic theory came from the law of constant
proportions given by Proust?
A n s w e r
According to law of constant proportions describes that, “a chemical
compound always contains same elements in deinite proportion by mass and
it does not depend on the source of compound.”
This law gives result to the postulate of Dalton’s atomic theory which states
that, “When two elements combine to form two or more than two different
compounds then the different masses of one element B which combine with
ixed mass of the other element bear a simple ratio to one another.”
7 . 	 Q u e s t i o n
Which ancient Indian philosopher suggested that all matter is composed of
very small particles? What name was given by him to these particles?
A n s w e r
Maharshi Kanada was ancient Indian scientist and sage who suggested that all
matter is composed of very small particles. He named the smallest particles
as “Parmanu” .
8 . 	 Q u e s t i o n
Name any two laws of chemical combination.
A n s w e r
Law of conservation of mass was given by Antoine Lavoisier in 1744.
According to this law, “Matter can neither be created nor destroyed in a
chemical reaction” .
Law of constant proportions was given by Joseph Proust in 1799. According
to this law, “a chemical compound always contains same elements in deinite
proportion by mass and it does not depend on the source of compound.”
9 . 	 Q u e s t i o n
‘If 100 grams of pure water taken from different sources is decomposed by
passing electricity, 11 grams of hydrogen and 89 grams of oxygen are always
obtained’. Which chemical law is illustrated by this statement?
A n s w e r
The above statement justiies the Law of constant proportions which was
given by Joseph Proust in 1799. According to this law, “a chemical compound
always contains same elements in deinite proportion by mass and it does not
depend on the source of compound.” This suggests that whatever be the
source of water, it will always contain 1:8 ratio of Hydrogen and oxygen
respectively.
1 0 . 	 Q u e s t i o n
‘If 100 grams of calcium carbonate (whether in the form of marble or chalk)
are decomposed completely, then 56 grams of calcium oxide and 44 grams of
carbon dioxide are obtained’. Which law of chemical combination is
illustrated by this statement?
A n s w e r
The above statement justiies the Law of constant proportions which was
given by Joseph Proust in 1799. According to this law, “a chemical compound
always contains same elements in deinite proportion by mass and it does not
depend on the source of compound.” This suggests that whatever be the
source of water, it will always contain 1:8 ratio of Hydrogen and oxygen
respectively.
1 1 . 	 Q u e s t i o n
What are the building blocks of matter?
A n s w e r
Matter is made up of indivisible particles known as Atoms. Atoms are the
building blocks of matter.
1 2 . 	 Q u e s t i o n
How is the size of an atom indicated?
A n s w e r
The size of an atom is indicated by its radius which is called atomic radius
(radius of an atom). Atomic radius is measured in nanometre (nm) (1 metre =
109 nanometres or 1nm = 10_9m).
1 3 . 	 Q u e s t i o n
Name the unit in which the radius of an atom is usually expressed.
A n s w e r
Atomic radius is measured in nanometre (nm) (1 metre = 109 nanometres or
1nm = 10_9m).
1 4 . 	 Q u e s t i o n
Write the relation between nanometer and metre.
A n s w e r
A nanometer is one billionth part of metre. 1 metre = 1/109 nanometres or
1nm = 10_9m).
1 5 . 	 Q u e s t i o n
The radius of an oxygen atom is 0.073 nm. What does the symbol ‘nm’
represent?
A n s w e r
The symbol ‘nm’ represents Nanometre. A nanometer is one billionth part of
metre. 1 metre = 1/109 nanometres or 1nm = 10_9m).
1 6 . 	 Q u e s t i o n
Why is it not possible to see an atom even with the most powerful
microscope?
A n s w e r
Atoms are the building blocks of the matter. They are very small in size.
Hence Why is it not possible to see an atom even with the most powerful
microscope.
1 7 . 	 Q u e s t i o n
State whether the following statement is true or false:
The symbol of element cobalt is CO.
A n s w e r
False, the symbol of element cobalt is Co.
1 8 . 	 Q u e s t i o n
Deine ‘molecular mass’ of a substance.
A n s w e r
The molecular mass of a substance (an element or a compound) can be
deined as the average relative mass of a molecule of the substance as
compared with mass of an atom of carbon (C-12 isotope) taken as 12 atomic
mass unit. The molecular mass of a substance can be determined by adding
atomic masses of all the atoms present in the molecule of the substance.
1 9 . 	 Q u e s t i o n
What is meant by saying that ‘the molecular mass of oxygen is 32’?
A n s w e r
The symbol of oxygen is O
2
 which means it contains two atoms of oxygen.
The molecular mass of one atom of oxygen is 16.
Hence the molecular mass of O
2
 is 32.
2 0 . 	 Q u e s t i o n
Fill in the following blanks with suitable words:
(a) In water, the proportion of oxygen and hydrogen is …….. by mass.
(b) In a chemical reaction, the sum of the masses of the reactants and the
products remains unchanged. This is called ………… .
A n s w e r
(a) 8:1, whatever be the source of water, it will always contain 1:8 ratio of
Hydrogen and oxygen respectively.
(b) Law of conservation of mass.
S h o r t 	 A n s w e r 	 T y p e 	 Q u e s t i o n s - P g - 1 2 9
2 1 	 A . 	 Q u e s t i o n
Name the element used as a standard for atomic mass scale.
A n s w e r
Carbon is the element used as a standard for atomic mass scale.
2 1 	 B . 	 Q u e s t i o n
Which particular atom of the above element is used for this purpose?
A n s w e r