NCERT Solutions for Class 9 Science Chapter 3 Atoms and Molecules

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NCERT Class 9 Science Chapter 3 Exercise Question Answer

Exercise-3.1 (Page: 32)

Q 1. In a reaction, 5.3 g of sodium carbonate reacted with 6 g of acetic acid. The products were 2.2 g of carbon dioxide, 0.9 g water and 8.2 g of sodium acetate. Show that these observations are in agreement with the law of conservation of mass.

sodium carbonate + acetic acid → sodium acetate + carbon dioxide + water

Answer:

Given, the reaction

sodium carbonate + acetic acid → sodium acetate + carbon dioxide + water

5.3g 6g 8.2g 2.2g 0.9g

Now,

Total Mass on the Left Hand Side = 5.3g + 6g = 11.3g

Total Mass on the Right Hand Side = 8.2g + 2.2g + 0.9g = 11.3g

As Mass on the LHS is equal to RHS, the observation is in agreement with the law of conservation of mass.

Q 2. Hydrogen and oxygen combine in the ratio of 1:8 by mass to form water. What mass of oxygen gas would be required to react completely with 3 g of hydrogen gas?

Answer:

Given:

Hydrogen and oxygen combine in the ratio of 1:8 by mass to form water.

Now,

For every 1 g of Hydrogen, 8 g of oxygen is needed for the reaction to take place.

Therefore, for 3 g of Hydrogen, the mass of oxygen needed = 8 * 3 = 24 g.

Hence, 24 g of Oxygen is needed to complete a reaction with 3 g of Hydrogen.

Q 3. Which postulate of Dalton’s atomic theory is the result of the law of conservation of mass?

Answer:

The postulate of Dalton’s atomic theory is the result of the law of conservation of mass is

"Atoms can neither be created nor can be destroyed".

Q 4. Which postulate of Dalton’s atomic theory can explain the law of definite proportions?

Answer:

The postulate of Dalton’s atomic theory can explain the law of definite proportions is

"The relative number and kinds of atoms are equal in given compounds."

CBSE NCERT Solutions for Class 9 Science Chapter 3 Atoms and Molecules

Exercise-3.2 (Page: 35)

Q 1. Define the atomic mass unit.

Answer:

An atomic mass unit is a unit of mass used to express the weight subatomic particles, where one unit is equal to exactly one-twelfth the mass of a carbon-12 atom.

Q 2. Why is it not possible to see an atom with naked eyes?

Answer:

We can't see the atom with the naked eye because they are minuscule in nature. they are measured in the nanometres. Also, except for noble gases, all-atom do not exist independently. they exist in the form of any compound.

NCERT Free Solutions for Class 9 Science Chapter 3 Atoms and Molecules

Exercise-3.3 and 3.4 (Page: 39)

Q 1. Write down the formulae of

(i) sodium oxide

(ii) aluminium chloride

(iii) sodium sulphide

(iv) magnesium hydroxide

Answer:

The Formula of the given compounds are :

(i) sodium oxide :

$\Rightarrow Na_2O$

(ii) aluminium chloride:

$\Rightarrow AlCl_3$

(iii) sodium sulphide:

$\Rightarrow Na_2S$

(iv) magnesium hydroxide:

$\Rightarrow Mg(OH)_2$

Q 2. Write down the names of compounds represented by the following formulae:

(i) $Al_{2}(SO_{4})_{3}$

(ii) $CaCl_{2}$

(iii) $K_{2}SO_{4}$

(iv) $KNO_{3}$

(v) $CaCO_{3}$

Answer:

The Names of the following compounds are :

(i) $Al_{2}(SO_{4})_{3}$

=Aluminium Sulphate

(ii) $CaCl_{2}$

=Calcium Chloride

(iii) $K_{2}SO_{4}$

=Potessium Sulphate

(iv) $KNO_{3}$

= Potassium Nitrate

(v) $CaCO_{3}$

= Calcium Carbonate.

Q 3. What is meant by the term chemical formula?

Answer:

The chemical formula of a compound is a symbolic representation of its composition. For example, The chemical formula for common salt is NaCl as it is made up of Sodium (Na) and Chlorine (Cl).

Q 4.(i) How many atoms are present in a

$H_{2}S$ molecule

Answer:

$H_{2}S$ molecule has 2 atoms of Hydrogen and 1 atom of Sulphur.

and hence,

A total of 3 atoms are present in $H_{2}S$ molecule.

Q 4.(ii) How many atoms are present in a

$PO_{4}^{3-}$ ion?

Answer:

$PO_{4}^{3-}$ ion has one atom of Phosphorus and 4 atoms of Oxygen.

And Hence,

A total of 5 atoms are present in $PO_{4}^{3-}$ ion.

Exercise-3.5.1-3.5.2 (Page: 40)

Q 1. Calculate the molecular masses of $H_{2}, O_{2},Cl_{2},CO_{2},CH_{4},C_{2}H_{6}, C_{2}H_{4}, NH_{3},CH_{3}OH$

Answer:

The molecular mass of $H_2$ :

= 2 * Atomic mass of Hydrogen

= 2 * 1u

=2u.

The molecular mass of $O_2$ :

= 2 * Atomic mass of Oxygen

= 2 * 16u

= 32u.

The molecular mass of $Cl_2$ :

= 2 * Atomic mass of Chlorine

= 2 * 35.5uu

= 71u.

The molecular mass of $CO_2$ :

= Atomic mass of Carbon +2 * Atomic mass of Oxygen

= 12u + 2 * 16u

= 44u.

The molecular mass of $CH_4$ :

= Atomic mass of Carbon +4 * Atomic mass of Hydrogen

= 12u + 4 * 1u

= 16u.

The molecular mass of $C_2H_6$ :

= 2 * Atomic mass of Carbon + 6 * Atomic mass of Hydrogen

= 2*12u+ 6 * 1u

=24u+ 6u

= 30u.

The molecular mass of $C_2H_4$ :

= 2 * Atomic mass of Carbon + 64* Atomic mass of Hydrogen

= 2*12u+ 4* 1u

=24u+ 4u

= 28u.

The molecular mass of $NH_3$ :

= Atomic mass of Nitrogen + 3 * Atomic mass of Hydrogen

= 14u+ 3 * 1u

= 17u.

The molecular mass of $CH_3OH$ :

= Atomic mass of Carbon +4 * Atomic mass of Hydrogen + Atomic mass of Oxygen

= 12u+ 4 * 1u + 16u

= 32u.

Q 2. Calculate the formula unit masses of ZnO, Na ₂ O, K ₂ CO ₃ , given atomic masses of Zn = 65 u, Na = 23 u, K = 39 u, C = 12 u, and O = 16 u

Answer:

Given,

the atomic mass of Zn = 65 u,

the atomic mass of Na = 23 u,

the atomic mass of K = 39 u,

the atomic mass of C = 12 u,

and the atomic mass of O = 16 u

Now,

Formula unit mass of ZnO = Atomic mass of Zinc + Atomic mass of O

= 65 u + 16 u

= 81 u.

Formula unit mass of Na ₂ O = 2 * Atomic mass of Na+ Atomic mass of O

= 2 * 23 u + 16 u

= 62 u.

Formula unit mass of K ₂ CO ₃ = 2 * Atomic mass of K+ Atomic mass of C + 3 * Atomic mass of O

= 2 * 39 u + 12 u + 3 * 16 u

= 138 u.

Atoms and molecules class 9 solved questions answers

Exercise-3.5.3 (Page: 42)

Q 1. If one mole of carbon atoms weighs 12 grams, what is the mass (in grams) of 1 atom of carbon?

Answer:

As we know,

$1\: mole=6.022\times10^{23}\:atoms$

Now,

the mass of 1 mole or $6.022\times10^{23}\:atoms$ = 12 g

The mass of 1 atom :

$=\frac{12}{6.022\times10^{23}}=1.99\times 10^{-23}\:g$

Hence the mass of 1 atom of Carbon is $1.99\times 10^{-23}\:g$ .

Q 2. Which has more number of atoms, 100 grams of sodium or 100 grams of iron (given, the atomic mass of Na = 23 u, Fe = 56 u)?

Answer:

The number of moles of 100 g Na atoms :

$=\frac{100}{23}=4.35\:moles$

The number of moles in 100 g of Fe atoms :

$=\frac{100}{56}=1.76\:moles$

As we know, the one-mole atoms contain $6.022\times10^{23}$ atoms.

So, more the number of moles, more the number of atoms. and hence 100 g of Na atom has a greater number of atoms than 100 g Fe.

Atoms and Molecules Class 9 NCERT Science Chapter 3 Excercise

Exercise Page - 43

Q 1. A 0.24 g sample of a compound of oxygen and boron was found by analysis to contain 0.096 g of boron and 0.144 g of oxygen. Calculate the percentage composition of the compound by weight.

Answer:

The total mass of the compound = 0.24 g

Mass of boron in the compound = 0.096 g

Mass of oxygen in the compound = 0.144 g

Now, As we know,

The percentage of an element in the compound :

$=\frac{total\:mass\:of\:element}{total\:mass\:of\:compound}\times 100$

So,

The percentage of Boron in the compound by weight :

$=\frac{0.096}{0.24}\times 100$

$=40\%$

The percentage of Oxygen in the compound by weight :

$=\frac{0.144}{0.24}\times 100$

$=60 \%$

Q 2. When 3.0 g of carbon is burnt in 8.00 g oxygen, 11.00 g of carbon dioxide is produced. What mass of carbon dioxide will be formed when 3.00 g of carbon is burnt in 50.00 g of oxygen? Which law of chemical combination will govern your answer?

Answer:

3.0 g of carbon combines with 8.0 g of oxygen to give 11.0 of carbon dioxide.

So, by the law of definite proportions,

When 3.00 g of carbon is burnt in 50.00 g of oxygen, only 8.00 g of oxygen will be used to produce 11.00 gram of carbon dioxide. The remaining 42.00 g of oxygen will remain unreacted. Law of constant proportion is Held.

Q 3. What are polyatomic ions? Give examples.

Answer:

Polyatomic ions are ions that contain more than one atom. These atoms can be of the same type or of a different type.

Some examples of polyatomic ions are NH ₄ ⁺ , OH ^- , SO ₄ ^2- , and SO ₃ ^2- .

Q 4. Write the chemical formulae of the following.

(a) Magnesium chloride

(b) Calcium oxide

(d) Aluminium chloride

(e) Calcium carbonate

Answer:

The chemical formula of Given compounds are :

(a) Magnesium chloride

$=MgCl_2$

(b) Calcium oxide

$=CaO$

(c) Copper nitrate

$=Cu(NO_3)_2$

(d) Aluminium chloride

$=AlCl_3$

(e) Calcium carbonate

$=CaCO_3$

Q 5. Give the names of the elements present in the following compounds.

(a) Quick lime

(b) Hydrogen bromide

(d) Potassium sulphate.

Answer:

The names of the elements present in the given compounds are :

(a) Quick lime :

$Cao$ = Calcium and Oxygen.

(b) Hydrogen bromide:

$HBr$ = Hydrogen and Bromine.

(c) Baking powder:

$NaHCO_3$ = Sodium, Hydrogen, Carbon, and Oxygen.

(d) Potassium sulphate:

$K_2SO_4$ = Potassium, Sulphur, and oxygen.

Q 6.(a) Calculate the molar mass of the following substances.

Ethylene , $C_{2}H_{2}$

Answer:

The molecular mass of ethyne, $C_{2}H_{2}$ = 2 * Atomic Mass of C + 2 * Atomic Mass of H

= 2 * 12u + 2 * 1u

= 24u + 2u

= 26u

Q 6. (b) Calculate the molar mass of the following substances.

Sulphur molecule , S ₈

Answer:

The molecular mass of Sulphur molecule, = 8 * Atomic Mass of S

= 8 * 32u

= 256u

Q 6.(c) Calculate the molar mass of the following substances

Baking soda

Answer:

The molecular formula of Baking soda is NaHCO3

So the molecular mass will be some of the individual atoms involved in the formula.

Molecular Mass of baking soda = Molecular mass (Na + H + C + 3xO)

= 23 + 1 + 12 + 3x16

= 84 g/mol

Q 6.(d) Calculate the molar mass of the following substances.

Hydrochloric acid, HCl

Answer:

The molecular mass of Hydrochloric acid, HCl = 1 * Atomic Mass of Cl + 1 * Atomic Mass of H

= 35.5 u + 1u

= 36.5u

Q 6. (e) Calculate the molar mass of the following substances.

Nitric acid, HNO₃

Answer:

The molecular mass of Nitric acid, HNO ₃ = 1 * Atomic Mass of N + 1 * Atomic Mass of H + 3 * Atomic Mass of O

= 1 * 14u + 1 * 1u + 3 * 16u

= 14u + 1u + 48u

= 63u

Q 7.(a) What is the mass of—

1 mole of nitrogen atoms?

Answer:

Atomic Mass of Nitrogen atom = 14 u.

Mass of one mole of nitrogen atoms = molecular mass of nitrogen atoms in grams

= 14 g

Q 7.(b) What is the mass of -

4 moles of aluminium atoms (Atomic mass of aluminium = 27)?

Answer:

The atomic mass of Aluminium = 27 u.

Mass of 4 moles of aluminium atoms = 4 x Mass of 1 mole of Al atoms

= 4 x molecular mass of aluminum atoms in grams

= 4 x 27

= 108 g

Q 7. (c) What is the mass of—

10 moles of sodium sulphite (Na₂SO₃)?

Answer:

The molecular mass of Sodium sulphite (Na₂SO₃) = 2 * 23 + 32 + 3 * 16

= 126u

Mass of 10 moles of sodium sulphite = 10 x Mass of 1 mole of Na ₂ SO ₃

= 10 x molecular mass of Na₂SO₃ in grams

= 10 x 126 g

= 1260 g.

Q 8.(a) Convert into a mole.

12 g of oxygen gas

Answer:

The molecular Mass of the Oxygen = 32 g

Now,

Since 32 g Oxygen = 1 mole

The number of moles in 12 g Oxygen:

$=\frac{1}{32}\times 12\:moles$

$=0.375\:moles$

Q 8.(b) Convert into mole.

20 g of water

Answer:

Given, Mass of water = 20 g

The Molecular mass of the water = 2 * Mass of Hydrogen + Mass of Oxygen

= 2 * 1 + 16

= 18 g.

Now, Number of moles :

$=\frac{given\:mass}{molar\:mass}=\frac{20}{18}=1.11\:moles$

Q 8.(c) Convert into mole.

22 g of carbon dioxide

Answer:

Given Mass of the carbon dioxide = 22 g.

The molecular mass of Carbon dioxide in grams = mass of Carbon + 2 * mass of Oxygen

= 12u + 2 * 16u

= 44u

The number of mole :

$=\frac{given\:mass}{molecular\:mass}=\frac{22}{44}=0.5\:moles$

Q 9 . (a) What is the mass of:

0.2 mole of oxygen atoms?

Answer:

The mass of 1 mole of oxygen atoms = 16 g

The mass of 0.2 mole of oxygen atoms = 0.2 x 16 g

= 3.2 g

Q 9.(b) What is the mass of:

0.5 mole of water molecules?

Answer:

The mass of 1 mole of water molecules = 18 g

Thus,

the mass of 0.5 mole of water molecules = 18 x 0.5

= 9.0 g

Q 10. Calculate the number of molecules of sulphur (S ₈ ) present in 16 g of solid sulphur.

Answer:

Given the mass of Sulphur = 16 g

The molecular mass of the Sulphur molecule = 8 x 32 = 256 g.

The number of moles of Sulphur molecule :

$=\frac{16}{256}$

$=0.0625\:moles$

Now

Number of molecules in 1 mole = $6.022\times 10^{23}$ molecules

So,

The number of molecules in 0.0625 moles = $0.0625\times6.022\times 10^{23}$ molecules.

= $3.76375\times 10^{22}$ Molecules.

Hence there are $3.76375\times 10^{22}$ Sulphur molecules in 16 g of solid sulphur .

Q 11. Calculate the number of aluminium ions present in 0.051 g of aluminium oxide.

Answer:

Give, the mass of Aluminum Oxide = 0.051 g.

The molecular mass of Aluminium Oxide = 2 x mass of Aluminium + 3 x mass of Oxygen.

= 2 x 27 + 3 x 16

= 102 g

Number of Moles of Aluminium Oxide :

$\frac{0.051}{102}=0.0005\:moles$

Now, Since 1 mole of Aluminium Oxide contain 2 moles of Aluminium ion,

The Number of Moles of Aluminium ion = 2 x number of moles of Aluminium Oxide

= 2 x 0.0005

= 0.001 moles.

Now, As the number of ion in 1 mole = $6.022\times10^{23}$ ions.

The number of ions in 0.001 moles of Aluminium ion = $0.001\times6.022\times10^{23}$ ions

= $6.022\times10^{20}$ ions.

Hence there are $6.022\times10^{20}$ Aluminium ions in 0.051 g of aluminium oxide.

NCERT Class 9 Science Chapter 3 Exercise Solutions

Class 9 science chapter 3 exercise question answer carries a substantial weight of 23 marks in exams, with questions covering a wide range of topics. To excel, students should master the entire chapter, particularly focusing on chemical formulae and numerical problem-solving. Key topics within this chapter encompass the Laws of Chemical Combination, Atom and Molecule fundamentals, Chemical Formulae, and crucial concepts like Molecular Mass and the Mole Concept.

NCERT Solutions for Class 9 Science- Chapter Wise

Chapter No.	Chapter Name
Chapter 1	Matter in Our Surroundings
Chapter 2	Is Matter Around Us Pure
Chapter 3	Atoms and Molecules
Chapter 4	Structure of The Atom
Chapter 5	The Fundamental Unit of Life
Chapter 6	Tissues
Chapter 7	Diversity in Living Organisms
Chapter 8	Motion
Chapter 9	Force and Laws of Motion
Chapter 10	Gravitation
Chapter 11	Work and Energy
Chapter 12	Sound
Chapter 13	Why Do We Fall ill?
Chapter 14	Natural Resources
Chapter 15	Improvement in Food Resources

NCERT Solutions for Class 9 Science Chapter 3 Atoms and Molecules - Important Topics

Some important topics covered in the chapter "Atoms and Molecules" in Class 9 Science include:

Introduction to atoms and molecules: Understanding the basic concepts of atoms, molecules, and their distinctions is the first step in understanding class 9 science chapter 3 exercise solutions.
Laws of Chemical Combination: Studying the laws that control how atoms and molecules behave during chemical reactions, including the Law of Conservation of Mass and the Law of Definite Proportions.
Atomic Mass and Molecular Mass: Calculate the atomic and molecular masses of atoms and compounds, respectively, using the terms "atomic mass" and "molecular mass."
Mole Concept: Understanding the relationship between moles, mass, and number of particles as well as the concept of a mole and Avogadro's number
Chemical Formulas: Learning how to write and interpret chemical formulas, including molecular formulas and empirical formulas.
Balancing Chemical Equations: Chemical equation balance is a skill that must be developed in order to ensure mass conservation.
Calculation Involving Atoms and Molecules: Solving problems related to the number of atoms, molecules, or ions in a given sample using the mole concept.

NCERT Solutions for Class 9 Science: Important Formulas and Diagrams + eBook link

Understanding class 9th chapter 3 science formulas is crucial for understanding atoms and molecules. They assist us in calculating the masses of molecules, counting atoms or molecules, and balancing chemical equations. You will be able to solve atoms and molecules class 9 questions and answers with confidence and learn more about the universe of atoms and molecules if you understand these formulae and use them along with the solutions to Class 9 Science Chapter 3.

1 nanometer (nm) is equal to 10^-9 meters (m)

1 nm = 10^-9 m

Number of moles (n) = Given quantity of substance (N) /Molar mass of substance (N_o)
Number of moles of atoms = Number of atoms Avogrdro's number [Avogrdro’s number=6.022 × 10^23]
Mass = Molar mass × Number of moles
Formula unit mass = (Atomic mass of cation × Number of cations) + (Atomic mass of anion × Number of anions)

In addition to the provided solutions, our subject matter experts at Careers360 have curated important Formulas For Class 9 Science - chapterwise PDF. This PDF serves as a valuable resource for quick revision during exams and study sessions. Students can download the PDF for free by clicking on the link provided above in the suggestion section, ensuring easy access to essential formulas at any time.

Key Features of NCERT Solutions for Class 9 Science Chapter 3 Atoms and Molecules:

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Accessibility: You can access these class 9 chapter 3 solutions at your convenience, anytime and anywhere, allowing for flexible study sessions and quick reference. Because solutions and formulas are available in the form of PDF as well.
Smooth Transition to Advanced Topics: Understanding and mastering these class 9th science chapter 3 atoms and molecules question answer will give students a strong basis for moving on to more advanced chemistry courses.

Dropped Topics – Mole concept

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NCERT Science Exemplar Solutions Class 9 - Chapter Wise

Chapter No.	Chapter Name
Chapter 1	Chapter 1 Matter in our Surroundings
Chapter 2	Chapter 2 Is Matter Around Us Pure?
Chapter 3	Chapter 3 Atoms and Molecules
Chapter 4	Chapter 4 Structure of the Atom
Chapter 5	Chapter 5 The Fundamental Unit of Life
Chapter 6	Chapter 6 Tissues
Chapter 7	Chapter 7 Diversity in Living Organisms
Chapter 8	Chapter 8 Motion
Chapter 9	Chapter 9 Forces and Laws of Motion
Chapter 10	Chapter 10 Gravitation
Chapter 11	Chapter 11 Work and Energy
Chapter 12	Chapter 12 Sound
Chapter 13	Chapter 13 Why do We Fall ill?
Chapter 14	Chapter 14 Natural Resources
Chapter 15	Chapter 15 Improvement in Food Resources

Frequently Asked Questions (FAQs)

1. How important is the Chapter Atoms And Molecules of Class 9 Science NCERT text book?

The chapter Atoms And Molecules of Class 9 NCERT syllabus is one of the basic chapter of chemistry that should be grasped well. This chapter is a part of Physical Chemistry. Questions from this chapter are important for Class 9 final exam as well as for scholarship exams like NSEJS. To get more questions on the chapter refer to NCERT exemplar for Class 9 Science Chapter 3 Atoms And Molecules.

2. Is the numercals in Atoms And Molecules Class 9 NCERT chapter 3 Important?

Yes as you can see all the questions given in the exercise are numerical based or chemical formula based. The numerical questions given are important to score well in Atoms And Molecules Chapter.

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Option 1) $0.34\; J$	Option 2) $0.16\; J$
Option 3) $1.00\; J$	Option 4) $0.67\; J$

Option 1) $2,000 \; J - 5,000\; J$	Option 2) $200 \, \, J - 500 \, \, J$
Option 3) $2\times 10^{5}J-3\times 10^{5}J$	Option 4) $20,000 \, \, J - 50,000 \, \, J$

Option 1) $K/2\,$	Option 2) $\; K\;$
Option 3) $zero\;$	Option 4) $K/4$

Option 1) $11.2\, L\, H_{2(g)}$ at STP is produced for every mole $HCL_{(aq)}$ consumed	Option 2) $6L\, HCl_{(aq)}$ is consumed for ever $3L\, H_{2(g)}$ produced
Option 3) $33.6 L\, H_{2(g)}$ is produced regardless of temperature and pressure for every mole Al that reacts	Option 4) $67.2\, L\, H_{2(g)}$ at STP is produced for every mole Al that reacts .

Option 1) 0.02	Option 2) 3.125 × 10^-2
Option 3) 1.25 × 10^-2	Option 4) 2.5 × 10^-2

Option 1) decrease twice	Option 2) increase two fold
Option 3) remain unchanged	Option 4) be a function of the molecular mass of the substance.

Option 1) Molality	Option 2) Weight fraction of solute
Option 3) Fraction of solute present in water	Option 4) Mole fraction.

Option 1) twice that in 60 g carbon	Option 2) 6.023 × 10²²
Option 3) half that in 8 g He	Option 4) 558.5 × 6.023 × 10²³

Option 1) less than 3	Option 2) more than 3 but less than 6
Option 3) more than 6 but less than 9	Option 4) more than 9

NCERT Solutions for Class 9 Science Chapter 3 Atoms and Molecules

NCERT Solutions Class 9 Science Atoms and Molecules – CBSE Free PDF Download

NCERT Solutions for Class 9 Science Chapter 3 Atoms and Molecules

Exercise-3.1 (Page: 32)

Exercise-3.2 (Page: 35)

Exercise-3.3 and 3.4 (Page: 39)

Exercise-3.5.1-3.5.2 (Page: 40)

Atoms and molecules class 9 solved questions answers

Exercise-3.5.3 (Page: 42)

Q 1. If one mole of carbon atoms weighs 12 grams, what is the mass (in grams) of 1 atom of carbon?

Atoms and Molecules Class 9 NCERT Science Chapter 3 Excercise

Exercise Page - 43

NCERT Class 9 Science Chapter 3 Exercise Solutions

NCERT Solutions for Class 9 Science- Chapter Wise

NCERT Solutions for Class 9 Science Chapter 3 Atoms and Molecules - Important Topics

NCERT Solutions for Class 9 Science: Important Formulas and Diagrams + eBook link

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