Download malhotra book depot

Chemistry
11
Anuj Kapoor
Based on the latest syllabus and
textbook(s) issued by CBSE/NCERT
MALHOTRA BOOK DEPOT
(Producers of Quality
Books)
An ISO 9001:2008 Certified Company
Price : ` 500.00
OUR ADDRESSES IN INDIA
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
New Delhi : MBD House, Gulab Bhawan, 6, Bahadur Shah Zafar Marg
Ph. 30912330, 30912301, 23318301
Mumbai : A-683, T.T.C. Industrial Area, M.I.D.C. Off. Thane-Belapur Road, Navi Mumbai
Ph. 32996410, 27780821, 8691053365
Chennai : No. 26 B/2 SIDCO Estate, North Phase, Pataravakkam Ambattur Industrial Estate, Ambattur
Ph. 26359376, 26242350
Chennai : Plot No. 3018, Old Y Block, 3rd Street, 12th Main Road, Anna Nagar West
Ph. 23741471
Kolkata : Satyam Building, 46-D, Rafi Ahmed Kidwai Marg
Ph. 22296863, 22161670
Jalandhar City : MBD House, Railway Road
Ph. 2458388, 2457160, 2455663
Bengaluru : 124/31, 1st Main, Industrial Town (Near Chowdeshwari Kalyan Mantap), West of Chord Road, Rajajinagar
Ph. 23103329, 23104667
Hyderabad : 3-4-492, Varun Towers, Barkatpura
Ph. 27564788, 9985820001
Ernakulam : Surabhi Building, South Janatha Road, Palarivattom
Ph. 2338107, 2347371
Pune : Survey No. 44, Behind Matoshree Garden, Kondhwa - Khadi Machine, Pisoli Road, At. Post-Pisoli
Ph. 65271413, 65275071
Nagpur : Near N.I.T. Swimming Pool, North Ambazari Road, Ambazari Layout
Ph. 2248104, 2248106, 2248649, 2245648
Ahmedabad : Godown No.10, Vedant Prabha Estate, Opp. ONGC Pumping Station, Sarkhej Sanand Road, Sarkhej
Ph. 26890336, 32986505
Cuttack : Badambadi, Link Road
Ph. 2367277, 2367279, 2313013
Guwahati : Chancellor Commercial, Hem Baruah Road, Paan Bazar
Ph. 2131476, 8822857385
Lucknow : 173/15, Dr. B. N. Verma Road, Old 30 Kutchery Road
Ph. 4010992, 4010993
Patna : Ist Floor, Annapurna Complex, Naya Tola
Ph. 2672732, 2686994, 2662472
Bhopal : Plot No. 137, 138, 139, Sector-I, Special Industrial Area, Govindpura
Ph. 2581540, 2601535
Jabalpur : 840, Palash Chamber, Malviya Chowk
Ph. 2405854
Goa : H. No. 932, Plot No. 66, Kranti Nagar (Behind Azad Bhawan), Alto Porvorim, Bardez
Ph. 2413982, 2414394
Jaipur : C-66A, In front of Malpani Hospital, Road No.1, V.K. Industrial Area, Sikar Road
Ph. 4050309, 4020168
Raipur : Behind Kailash Provision Store, Ravi Nagar
Ph. 4052529, 2445370
Karnal : Plot No. 203, Sector-3, HSIDC, Near Namaste Chowk, Opp. New World
Ph. 2220006, 2220009
Shimla (H.P.) : C-89, Sector-I, New Shimla-9
Ph. 2670221,2670618
Jammu (J&K) : MBD Office, 48 Gujjar Colony, C/o Gurjar Desh Charitable Trust, N.H. Bye Pass Road
Ph. 2467376, 9419104035
Ranchi (Jharkhand) : Shivani Complex, 2nd Floor, Jyoti Sangam Lane, Upper Bazar
Ph. 9431257111
Sahibabad (U.P.) : B-9 & 10, Site IV, Industrial Area
Ph. 3100045, 2896939
Dehradun (Uttarakhand) : Plot No. 37, Bhagirathipuram, Niranjanpur, GMS Road
Ph. 2520360, 2107214
DELHI LOCAL OFFICES:
q Delhi (Shakarpur) : MB 161, Street No. 4
q Delhi (Daryaganj) : MBD House, 4587/15, Opp. Times of India
q Delhi (Patparganj) : Plot No. 225, Industrial Area
Ph. 22546557, 22518122
Ph. 23245676
Ph. 22149691, 22147073
MBD BOOKS FOR XI (C.B.S.E.)
r MBD Super Refresher English (Core)
r MBD Super Refresher Hindi (Elective & Core)
r MBD Sanskrit Guide
r MBD Physics Refresher
r MBD Chemistry Refresher
r MBD Biology Refresher
r MBD Super Refresher Mathematics
r MBD Accountancy Refresher
r MBD Business Studies Refresher
r MBD Super Refresher Economics (Statistics for
Economics & Indian Economic Development)
r MBD Political Science Refresher
(Indian Constitution at work and Political Theory)
r MBD History Refresher
(Themes in World History)
r MBD Geography Refresher
r MBD Sociology
r MBD Super Refresher Punjabi
r MBD Super Refresher Physical Education
We are committed to serve students with best of our knowledge and resources. We have taken utmost care and attention while editing and
printing this book but we would beg to state that Authors and Publishers should not be held responsible for unintentional mistakes that might
have crept in. However, errors brought to our notice, shall be gratefully acknowledged and attended to.
© All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic,
mechanical, photocopying, recording, or otherwise without the prior written permission of the publisher. Any breach will entail legal action and prosecution
without further notice.
Published by:
MALHOTRA BOOK DEPOT
MBD House, Railway Road, Jalandhar City.
Printed at:
HOLY FAITH INTERNATIONAL (P) LTD.
B-9 & 10, Site-IV, Industrial Area, Sahibabad (U.P.)
SYLLABUS
CHEMISTRY
CLASS–XI
Total Periods (Theory 160 + Practical 60)
70 Marks
Time: 3 Hours
Unit No.
Title
No. of Periods
Unit I
Some Basic Concepts of Chemistry
12
Unit II
Structure of Atom
14
Unit III
Classification of Elements and Periodicity in Properties
08
Unit IV
Chemical Bonding and Molecular Structure
14
Unit V
States of Matter: Gases and Liquids
12
Unit VI
Chemical Thermodynamics
16
Unit VII
Equilibrium
14
Unit VIII
Redox Reactions
06
Unit IX
Hydrogen
08
Marks
11
04
21
16
Unit X
s-Block Elements
10
Unit XI
Some p-Block Elements
14
Unit XII
Organic Chemistry: Some Basic Principles and Technique
14
Unit XIII
Hydrocarbons
12
Unit XIV
Environmental Chemistry
06
Total
Unit 1:
Some Basic Concepts of Chemistry
160
18
70
(Periods 12)
General Introduction: Importance and scope of chemistry.
Nature of matter, laws of chemical combination, Dalton’s atomic theory: concept of elements, atoms and
molecules.
Atomic and molecular masses, mole concept and molar mass, percentage composition, empirical and molecular
formula, chemical reactions, stoichiometry and calculations based on stoichiometry.
Unit II: Structure of Atom
(Periods 14)
Discovery of electron, proton and neutron, atomic number, isotopes and isobars. Thompson’s model and its limitations.
Rutherford’s model and its limitations, Bohr’s model and its limitations, concept of shells and subshells, dual nature of
matter and light, de Broglie’s relationship, Heisenberg uncertainty principle, concept of orbitals, quantum numbers,
shapes of s, p and d orbitals, rules for filling electrons in orbitals–Aufbau principle, Pauli’s exclusion principle and Hund’s
rule, electronic configuration of atoms, stability of half filled and completely filled orbitals.
Unit III: Classification of Elements and Periodicity in Properties
(Periods 08)
Significance of classification, brief history of the development of periodic table, modern periodic law and the present
form of periodic table, periodic trends in properties of elements – atomic radii, ionic radii, inert gas radii, ionization
enthalpy, electron gain enthalpy, electronegativity, valency. Nomenclature of elements with atomic number greater
than 100.
Unit IV: Chemical Bonding and Molecular Structure
(Periods 14)
Valence electrons, ionic bond, covalent bond, bond parameters, Lewis structure, polar character of covalent bond,
covalent character of ionic bond, valence bond theory, resonance, geometry of covalent molecules, VSEPR theory,
concept of hybridization, involving s, p and d orbitals and shapes of some simple molecules, molecular orbital theory of
homonuclear diatomic molecules (qualitative idea only), hydrogen bond.
Unit V: States of Matter: Gases and Liquids
(Periods 12)
Three states of matter, intermolecular interactions, types of bonding, melting and boiling points, role of gas laws in
elucidating the concept of the molecule, Boyle’s law, Charle’s law, Gay Lussac’s law, Avogadro’s law, ideal behaviour,
empirical derivation of gas equation, Avogadro’s number, ideal gas equation. Deviation from ideal behaviour, liquefaction
of gases, critical temperature, kinetic energy and molecular speeds (elementary idea), Liquid State – vapour pressure,
viscosity and surface tension (qualitative idea only, no mathematical derivations).
Unit VI: Chemical Thermodynamics (Periods 16)
Concepts of system and types of systems, surroundings, work, heat, energy, extensive and intensive properties, state
functions. First law of thermodynamics – internal energy and enthalpy, heat capacity and specific heat, measurement of DU
and DH, Hess’s law of constant heat summation, enthalpy of bond dissociation, combustion, formation, atomization,
sublimation, phase transition, ionization, solution and dilution. Second law of Thermodynamics (brief introduction).
Introduction of entropy as a state function, Gibb’s energy change for spontaneous and non-spontaneous processes,
criteria for equilibrium.
Third law of thermodynamics (brief introduction).
Unit VII: Equilibrium
(Periods 14)
Equilibrium in physical and chemical processes, dynamic nature of equilibrium, law of mass action, equilibrium constant,
factors affecting equilibrium – Le Chatelier’s principle, ionic equilibrium – ionization of acids and bases, strong and weak
electrolytes, degree of ionization, ionization of poly basic acids, acid strength, concept of pH, Henderson Equation,
hydrolysis of salts (elementary idea), buffer solution, solubility product, common ion effect (with illustrative examples).
Unit VIII: Redox Reactions (Periods 06)
Concept of oxidation and reduction, redox reactions, oxidation number, balancing redox reactions, in terms of loss and gain
of electrons and change in oxidation number, applications of redox reactions.
Unit IX: Hydrogen (Periods 08)
Position of hydrogen in periodic table, occurrence, isotopes, preparation, properties and uses of hydrogen, hydrides–ionic,,
covalent and interstitial, physical and chemical properties of water, heavy water, hydrogen peroxide – preparation, reactions
and structure and use, hydrogen as a fuel.
Unit X: s-Block Elements (Alkali and Alkaline Earth Metals)
(10 Periods)
Group 1 and Group 2 Elements: General introduction, electronic configuration, occurrence, anomalous properties of
the first element of each group, diagonal relationship, trends in the variation of properties (such as ionization enthalpy,
atomic and ionic radii), trends in chemical reactivity with oxygen, water, hydrogen and halogens, uses.
Preparation and Properties of Some Important Compounds:
Sodium Carbonate, Sodium Chloride, Sodium Hydroxide and Sodium Hydrogencarbonate, Biological importance of
sodium and potassium. Calcium Oxide and Calcium Carbonate and their industrial uses, biological importance of Magnesium and Calcium.
Unit XI: Some p-Block Elements
(Periods 14)
General Introduction to p-Block Elements
Group 13 Elements: General introduction, electronic configuration, occurrence, variation of properties, oxidation
states, trends in chemical reactivity, anomalous properties of first element of the group, Boron – physical and chemical
properties, some important compounds, Borax, Boric acid, Boron Hydrides, Aluminium: Reactions with acids and
alkalies, uses.
Group 14 Elements: General introduction, electronic configuration, occurrence, variation of properties, oxidation states,
trends in chemical reactivity, anomalous behaviour of first elements. Carbon-catenation, allotropic forms, physical and
chemical properties; uses of some important compounds: oxides. Important compounds of silicon and a few uses:
Silicon Tetrachloride, Silicones, Silicates and Zeolites, their uses.
Unit XII: Organic Chemistry – Some Basic Principles and Technique
(Periods 14)
General introduction, methods of purification, qualitative and quantitative analysis, classification and IUPAC nomenclature
of organic compounds. Electronic displacements in a covalent bond: inductive effect, electromeric effect, resonance
and hyper conjugation. Homolytic and heterolytic fission of a covalent bond: free radicals, carbocations, carbanions,
electrophiles and nucleophiles, types of organic reactions.
Unit XIII: Hydrocarbons
(Periods 12)
Classification of Hydrocarbons
Aliphatic Hydrocarbons:
Alkanes: Nomenclature, isomerism, conformation (ethane only), physical properties, chemical reactions including free
radical mechanism of halogenation, combustion and pyrolysis.
Alkenes: Nomenclature, structure of double bond (ethene), geometrical isomerism, physical properties, methods of
preparation, chemical reactions: addition of hydrogen, halogen, water, hydrogen halides (Markownikov’s addition and
peroxide effect), ozonolysis, oxidation, mechanism of electrophilic addition.
Alkynes: Nomenclature, structure of triple bond (ethyne), physical properties, methods of preparation, chemical
reactions: acidic character of alkynes, addition reaction of–hydrogen, halogens, hydrogen halides and water.
Aromatic hydrocarbons : Introduction, IUPAC nomenclature, benzene: resonance, aromaticity, chemical properties:
mechanism of electrophilic substitution, Nitration, sulphonation, halogenation, Friedel Craft’s alkylation and acylation,
directive influence of functional group in monosubstituted benzene. Carcinogenicity and toxicity.
Unit XIV: Environmental Chemistry
(Periods 06)
Environmental pollution – air, water and soil pollution, chemical reactions in atmosphere, smog, major atmospheric
pollutants, acid rain, ozone and its reactions, effects of depletion of ozone layer, greenhouse effect and global
warming – pollution due to industrial wastes, green chemistry as an alternative tool for reducing pollution, strategies
for control of environmental pollution.
QUESTION PAPER DESIGN
CLASS-XI
CHEMISTRY (CODE NO. 043)
S.
Typology of Questions
No.
Time-3 Hours
Marks-70
Very
Short
Short
Value
Long
Total
%
Short
Answer-I
Answer-II
Based
Answer
Marks
Weightage
Answer
(SA-I)
(SA-II)
Question
(LA)
(VSA)
(2 Marks)
(3 Marks)
(4 Marks)
(5 Marks)
2
1
1
–
–
7
10%
–
2
4
–
1
21
30%
(1 Mark)
1.
Remembering—(Knowledge
based Simple recall questions,
to know specific facts, terms,
concepts, principles, or
theories, Identify, define, or
recite, information)
2.
Understanding
Comprehension—(to be
familiar with meaning and
to understand conceptually,
interpret, compare, contrast,
explain, paraphrase,
information).
3.
Application—(Use abstract
information in concrete
situation, to apply knowledge
to new situations, Use
given content to interpret a
situation, provide an example,
or solve a problem).
–
2
4
–
1
21
30%
4.
High Order Thinking
2
–
1
–
1
10
14%
1
–
2
1
–
11
16%
5×1=5
5×2=10
12×3=36
1×4=4
3×5=15
70(26)
100%
Skills (Analysis &
Synthesis)—(Classify,
compare, contrast, or
differentiate between different
pieces of information;
Organize and/or integrate
unique pieces of information
from a variety of sources).
5.
Evaluation—(Appraise,
judge, and/or justify the
value or worth of a decision
or outcome, or to predict
outcomes based on values).
TOTAL
QUESTION WISE BREAK UP
Type of Question
Mark per Question
Total No. of Questions
Total Marks
VSA
1
5
05
SA-I
2
5
10
SA-II
3
12
36
VBQ
4
1
04
LA
5
3
15
26
70
Total
1. Internal Choice: There is no overall choice in the paper. However, there is an internal choice in one question of 2 marks
weightage, one question of 3 marks weightage and all the three questions of 5 marks weightage.
2. The above template is only a sample. Suitable internal variations may be made for generating similar templates keeping the
overall weightage to different form of questions and typology of questions same.
Super Refresher
All chapters as per CBSE
Syllabus and NCERT Textbooks
Every chapter divided
into Sub-topics
NCERT Textbook
Questions with answers
NCERT Exemplar
Problems
with answers
Additional Important
Questions
with answers
Chemistry
Variety of
Value Based
Questions
HOTS
questions with answers
in every chapter
Model
Test
Papers for
Practice
CONTENTS
1Some Basic Concepts of Chemistry
1–40
2Structure of Atom
41–83
3Classification of Elements and Periodicity in Properties
84–116
4Chemical Bonding and Molecular Structure
117–171
5States of Matter
172–202
6Thermodynamics
203–239
7Equilibrium
240–305
306–343
8
Redox Reactions
9Hydrogen
344–376
10 s-Block Elements
377–406
11 Some p-Block Elements
407–435
12 Organic Chemistry (Some Basic Principles and Techniques)
436–486
13 Hydrocarbons
487–527
14 Environmental Chemistry
528–549
Model Question Papers for Practice
1 –
1
Some Basic Concepts of
Chemistry
CONCEPTS
1.1 Chemistry and its Importance
1.2 Units and Scientific notations
1.3 Matter and its Classification
1.4 Laws of Chemical Combination
1.5 Molecular formula and Mole Concept
1.6. Chemical stoichiometry and Solutions.
BASICS & BASIS
1.1 Chemistry and its Importance
of chemistry are Physical chemistry, Organic
chemistry, Inorganic chemistry and
Analytical chemistry etc.
p Importance of Chemistry. Chemistry plays
an important role in meeting human needs for
food, health care products and other materials
aimed at improving the quality of life.
p Chemistry may be defined as that branch of
science which deals with the study of atoms,
molecules and their transformations. Or It is that
branch of science which deals with the study of
composition, structure and properties of matter.
p Branches of Chemistry. The main branches
1.
Ans.
2.
Ans.
3.
Ans.
The medicines used to reduce tension are
called ............ .
Tranquilizers.
4.
Name the important branches of
chemistry.
Ans.
5.
These are Physical chemistry, Inorganic
chemistry and Organic chemistry.
Ans.
What is AZT ? Give its use.
AZT is Azidothymidine. It is used for AIDS
victims.
Name two chemical compounds which
are used in the treatment of cancer.
Cis-platin and taxol.
Name the compound which is generally
added for the sterilization of water.
Chlorine (0.2 to 0.4 ppm).
p Fundamental or basic units. There are
1.2 Units and Scientific Notations
p Physical quantities. Properties of matter
seven physical quantities, which have
independent units which cannot be derived
from any other unit. These are known as
fundamental or basic units.
like mass, length, time and temperature etc.
are expressed in terms of their numerical
values with appropriate units are termed as
physical quantities.
1
CHP-01.pmd
1
9/7/2016, 2:53 PM
2
MBD Super Refresher Chemistry-XI
p S.I. System (Systems Internationale). Seven basic units in S.I. system are as follows :
1.
2.
3.
4.
5.
6.
7.
Quantity
Units
Symbol
Length (l)
Mass (m)
Time (t)
Temperature (T)
Amount of substance (n)
Electric current (I)
Luminous intensity (I0)
metre
kilogram
second
kelvin
mole
ampere
candela
m
kg
s
K
mol
A
cd
p Derived units. The units of various physical quantities that could be derived from seven basic units
are known as derived units. Some common derived units have been tabulated as follows :
Some common derived units
Physical quantity
Relation with other
basic quantities
Force
Pressure
Energy, work
Power
Electric charge
Potential difference
Mass × acceleration
Force per unit area
Force × distance travelled
Energy / Time
Current × Time
—
m2
m3
kg/m3
or kg m–3
m/s or m s-1
m/s × 1/s
or m s–2
newton
pascal
joule
watt
coulomb
volt
Electric resistance
Potential difference/current
ohm
Area
Volume
Density
Speed
Acceleration
Electrical conductance
Frequency
(Length)2
(Length)3
Mass per unit volume
Distance travelled per unit time
Speed change per unit time
1
Resistance
Cycles/sec
p Precision and accuracy. Closeness of values
among a set of measurements of a physical
quantity is known as precision while closeness
of single measurement of a value to its true
value is termed as accuracy.
p Scientific Notation. Very large or very
small numbers are generally expressed in
exponential form or scientific notations. In
scientific notations, a number is expressed as
N × 10n
‘N’ is called digit term and is a number
CHP-01.pmd
Units
2
Symbol
—
—
—
—
—
—
—
N (= kg m s–2)
Pa (= kg m–1s–2)
J (= kg m s–2 × m or kg m2 s–2)
W (= kg m2 s–3 or Js–1)
C (= As)
V (= kg m2 s–3 or J A–1 s–2
or JC–1)
Ω (= VA–1)
ohm–1 or siemen S (= AV–1)
hertz
Hz (= s–1)
between 1.0 and 9.999 while ‘n’ is also a number
(a single or a multiple number) known as
exponent. For numbers greater than 9.999, ‘n’
has positive value, while for numbers less than
1, ‘n’ has a negative value.
p Significant figures. Significant figures are
the digits in a precisely recorded
measurement.
Significant figures in a number are all the
certain digits plus one doubtful digit at the
end of the number.
9/7/2016, 2:53 PM
3
Some Basic Concepts of Chemistry
1.
Ans.
2.
Ans.
3.
What is the SI units of density ?
kgm–3
What is the atomicity of hydrogen ?
Two.
–273ºC = ............ K.
1.3 Matter and its Classification
p Matter
Anything that has mass and occupies space and
can be felt by one or more of the known five senses
is known as matter. Classification of matter :
I. Physical Classification. Depending upon
the physical state, matter could be classified
into (a) solid state ( b) liquid state
(c) gaseous state.
II. Chemical Classification. Based upon its
composition, matter could be classified into
following three types : (1) elements
(2) compounds (3) mixtures.
1. Element. It is a pure substance which can
neither be built up from nor decomposed into
two or more still simpler substances by any
known physical or chemical methods. e.g.
carbon, iron, hydrogen, sulphur etc.
Elements may further be sub-divided into
(a) Metals e.g. Na, Mg, Al, Fe etc.
1.
Why is air sometimes considered as a
heterogeneous mixture ?
Ans.
This is due to the presence of dust particles
which donot mix with gas homogeneously.
2.
Ans.
Which of the following are compounds ?
Milk, 22 carat gold, Diamond, Ice.
Ice.
1.4 Laws of Chemical Combination
1. The Law of Conservation of Mass. It states
that total mass of the reactants is always equal
to that of the products during any physical or
chemical change.
Or
Matter can neither be created nor destroyed
by any known physical or chemical change.
This law is also known as “The Law of
indestructibility of Matter”.
CHP-01.pmd
3
Ans.
4.
Ans.
5.
Ans.
0.
What is the SI units of molarity ?
mol dm–3.
How many basic units are present in
SI system ?
Seven.
(b) Metalloids e.g. As, Sb etc.
(c) Non-metals e.g. O, N, S, P, Cl etc.
(d) Noble gases e.g. He, Ne, Ar, Kr etc.
2. Compound. It is a substance which can be
obtained by the combination of atoms of two
or more, same or different elements combined
together in a definite ratio by weight.
e.g., Cl2, SO2, NaCl etc.
3. Mixture. A combination of two or more elements
or compounds in any proportion so that they
may not lose their identity is known as a
mixture. Mixtures are further of two types :
(a) Homogeneous mixtures. In this case the
composition of the mixture is the same throughout
the mixture and the constituents are
indistinguishable e.g. air, gasoline, alloys etc.
(b) Heterogeneous mixtures. In such mixtures
the composition is not the same throughout
the mixture and the components could be
easily separated e.g. a mixture of sand and
common salt, iron filings and sulphur.
3.
Ans.
4.
Ans.
5.
Ans.
Give two examples of homogeneous
mixtures.
(i) Sodium chloride mixed with water
(ii) 22-carat gold.
What are the different states of water ?
These are solids, liquids and gases.
Give two examples of metalloids.
Arsenic, antimony.
2. The Law of Definite Proportions Or Law
of constant composition. It states that a
pure chemical compound is always made up
of the same elements combined together in the
same fixed ratio by mass.
3. The Law of Multiple Proportions. It states
that when two elements combine to form two
or more compounds, the weights of one of the
elements which combine with the fixed weight
of the other element bear a simple whole
number ratio to one another.
9/7/2016, 2:53 PM
4
MBD Super Refresher Chemistry-XI
4. Law of Reciprocal Proportions. It states
that when two elements combine separately
with the fixed weight of a third element, the
ratio of their weights is either the same or a
simple whole number multiple of the ratio in
which they also combine with each other.
5. Gay Lussac’s Law of Combining
Volumes. It states that whenever gases react
with each other they do so in a simple ratio by
volumes to each other as well as to products
formed in the gaseous state all volumes being
measured under similar conditions of
temperature and pressure.
p Dalton’s atomic theory
The basic postulates of the theory are :
(i) All matter is made up of extremely small
indivisible particles known as atoms.
(ii) Atoms of an element are identical in every
respect i.e. of mass, shape, size and
properties.
(iii) Atoms of different elements are different in
all respects from one another.
(iv) Atom is the smallest unit of matter that takes
part in chemical reactions.
(v) Atoms of same or different elements combine
together in a definite ratio by mass to form
compound atoms (later on termed as
molecules).
1.
Ans.
2.
Ans.
3.
Is law of constant composition true for
all types of compounds ?
No, it is not true when isotopes of elements
are involved.
What are isotopes ?
These are the atoms of same element having
same atomic number but different mass
numbers.
What is law of conservation of mass and
energy ?
(vi) Atom can neither be created nor destroyed
by any physical or chemical methods.
Dalton’s atomic theory has been suitably modified
due to the discovery of isotopes and isobars,
sub-atomic particles like electrons, protons and
neutrons, destruction and subsequent conversion
of mass into energy, however the basic fabric of
the theory holds good even today.
p Modified atomic theory
(i) An atom is the smallest particle of matter
that takes part in a chemical reaction and
may or may not be capable of independent
existence.
(ii) A molecule is a smallest unit of matter,
capable of independent existence.
(iii) Under similar conditions of temperature
and pressure, equal volumes of all the gases
contain equal number of molecules.
Avogadro’s hypothesis has following
applications :
(i) To deduce the atomicity of elementary
gases.
(ii) To establish a relationship between the
vapour density and the molecular mass of
a gas or vapour.
(iii) To establish a relationship between the
molar mass and the molar volume.
Ans.
4.
Ans.
5.
Ans.
It states that mass and energy are
interconvertible but sum of mass and energy
always remains constant.
Which law of combination is not
explained by Dalton’s atomic theory ?
Law of Gaseous volumes.
Which law of combination does not
involve masses ?
Law of Gaseous volumes.
1.5 Molecular Formula and Mole Concept
p Atomic mass unit (amu). It is 1/12th of the
mass of an atom of carbon (C12-isotope).
Atomic mass of an element is the average
relative mass of the atom of an element as
compared to the mass of an atom of carbon
(C12) taken as 12 amu. Today, amu has been
replaced by ‘u’ which is known as unified
mass.
p Molecular mass of a substance may also be
defined as :
CHP-01.pmd
4
The average relative mass of a molecule of a
substance as compared with the mass of an
atom of carbon (C12) taken as 12 amu. For
ionic substances, the term formula mass is
used instead of molecular mass since such
substances do not exist in the form of
molecules.
The molecular/formula mass of a molecular
species is the sum of the atomic masses of all
the atoms in a formula unit of the substance.
9/7/2016, 2:53 PM
MBD CBSE Super Refresher Chemistry
For Class 11
40%
OFF
Publisher : MBD Group
Publishers
Author : Anuj Kapoor
Type the URL : http://www.kopykitab.com/product/10005
Get this eBook