Chapter 1 of Modern Chemistry for Class XI by Dr. S.P. Jauhar
Contents
1.1 Importance of Studying Chemistry
1.2 Physical quantities and their S.I. Units
1.3 Dimensional Analysis
1.4 Measurement and Significant Figures
1.5 Chemical Classification of Matter
1.6 Laws of Chemical Combination
1.7 Dalton Atomic Theory
1.8 Avogadro's Hypothesis
1.9 Atoms and Molecules
1.10 Atomic and Molecular Mass
1.11 Mole Concept
1.12 Mass-Mole Conversions
1.13 Percentage Composition and Molecular Formula
1.14 Stoichiometry of Chemical Equations
1.15 Stoichiometric Calculations
1.16 Limiting Reactant
1.17 Solution Stoichiometry
1.18 Stoichiometry of of Reactions in Solutions
The chapter is 100 pages
Study Plan
Basic plan is that each chapter is to be completed in 20 days. First 10 days theory portion is to be completed. Next 10 days, some revision of theory portion is to be done and some problems have to be done. In total 20 days all problems in the chapter have to be done. You have to mark all problems which you feel are difficult problems for a revision at a later date and for examinations.
Day 1
1.1 Importance of Studying Chemistry
1.2 Physical quantities and their S.I. Units
1.3 Dimensional Analysis
Ex. 1.1 to 1.5
Day 2
1.4 Measurement and Significant Figures
Ex. 1.6 to 1.14
Practce Problems 1.1 to 1.5
Day 3
1.5 Chemical Classification of Matter
1.6 Laws of Chemical Combination
Ex. 1.15 to 1.19
Practice Problems 1.9 to 1.12
Day 4
1.7 Dalton Atomic Theory
1.8 Avogadro's Hypothesis
1.9 Atoms and Molecules
1.10 Atomic and Molecular Mass
Ex. 1.20 to 1.23
Practice Problems 1.17 to 1.20
Day 5
P.P 1.21 to 1.25
P.P 1.26 to 1.30
Day 6
1.11 Mole Concept
Ex. 1.24 t0 1.25
1.12 Mass-Mole Conversions
Ex. 1.26 to 1.32
Day 7
Ex. 1.33 to 1.44
Day 8
P.P 1.31 to 1.45
Day 9
1.13 Percentage Composition and Molecular Formula
Ex. 1.45 to 1.52
Day 10
P.P. 1.46 ot 1.53
1.14 Stoichiometry of Chemical Equations
Day 11
Ex. 1.52 to 1.54
P.P. 1.54 to 1.55
Day 12
1.15 Stoichiometric Calculations
ex. 1.55 to 1.71
Day 13
P.P. 1.56 to 63
1.16 Limiting Reactant
Ex. 1.72 to 1.73
Day 14
1.17 Solution Stoichiometry
Ex. 1.74 to 1.80
P.P. 1.64 to 1.70
Day 15
1.18 Stoichiometry of Reactions in Solutions
Ex. 1.81 to 1.84
P.P. 1.71 to 1.75
Revision Period
Day 16
Conceptual Questions with Answers: 1 to 23
Day 17
Additional Numerical Problems for Practice: 1 to 10
Day 18
Additional Numerical Problems for Practice: 11 to 20
Day 19
Revision Exercises: Very Short Answer questions: 1 to 15
Day 20
Revision Exercises: Very Short Answer questions: 16 to 30
Day 21
Revision Exercises :Short Answer Questions 1 to 10
Day 22
Revision Exercises :Short Answer Questions 11 to 20
Day 23
Competition File: Illustration Problems: 1 to 5
Day 24
Competition File: Numerical Problems: 1 to 8
Day 25
Competition File: Numerical Problems: 9 to 16
Day 26
Competition File: Numerical Problems: 17 to 25
Day 27
Competition File: Objective Questions: 1 to 20
Day 28
Competition File: Objective Questions: 21 to 40
Day 29
Fill in the blanks: 10
True or False: 10
Day 30
Concept Review
Formula Review
Problems have to be included
Tampilkan postingan dengan label Basic concepts. Tampilkan semua postingan
Tampilkan postingan dengan label Basic concepts. Tampilkan semua postingan
Rabu, 11 Maret 2009
Minggu, 28 Desember 2008
Physical Chemistry - General topics- Study Guide - IIT JEE
The concept of atoms and molecules; Dalton's atomic theory;
Mole concept; Chemical formulae; Balanced chemical equations; Calculations (based on mole concept) involving common oxidation-reduction, neutralisation, and displacement reactions;
Concentration in terms of mole fraction, molarity, molality and normality.
Mole concept; Chemical formulae; Balanced chemical equations; Calculations (based on mole concept) involving common oxidation-reduction, neutralisation, and displacement reactions;
Concentration in terms of mole fraction, molarity, molality and normality.
Rabu, 24 Desember 2008
Concept of Acids and Bases - Application to Organic Compounds
Bronsted-Lowry theory
Acid is a proton donor and based is proton acceptor.
Any compound that has a hydrogen atom can act as a Bronsted-Lowry acid.
Hence H-A is used as general representation for an acid (H represents hydrogen)
Lewis Theory
According to Lewis theory, any molecule that has an electron deficient atom (site) that can accept a pair of electrons, is an acid.
Conjugate acid
Conjugate base
Acidity constant
Ph value
The effects of structure of the molecule on the strengths of acids and bases
Acids and Bases - Videos on Knol
Acid is a proton donor and based is proton acceptor.
Any compound that has a hydrogen atom can act as a Bronsted-Lowry acid.
Hence H-A is used as general representation for an acid (H represents hydrogen)
Lewis Theory
According to Lewis theory, any molecule that has an electron deficient atom (site) that can accept a pair of electrons, is an acid.
Conjugate acid
Conjugate base
Acidity constant
Ph value
The effects of structure of the molecule on the strengths of acids and bases
Acids and Bases - Videos on Knol
Bonding Concepts - Organic Compounds
Valency
Electronegativity
polarity
Dipole momennt
Atomic orbitals
Molecular orbitals
Hybridisation
Resonance
Electronegativity
polarity
Dipole momennt
Atomic orbitals
Molecular orbitals
Hybridisation
Resonance
Minggu, 29 Juni 2008
Why is SO3 is Lewis Acid?
I remember somebody asking this question in comments. I could not locate the answer at that time in the books that I referred to at that time.
Today I came across the issue in Inorganic Chemistry by Dr.O.P.Tandon, 2007 edition, page 120.
It says
Molecules haivng a multiple bond between atoms of dissimilar electronegativity act as Lewis acids. Typical examples of molecules belonging to this class of Lewis acids are CO2, SO2 and SO3. Under the influence of attacking Lewis base, one π-electron pair will be shifted towardsmore negative atom.
In page 128 question (viii) is more direct.
So# has acidic behaviour. Explain
Hint:Sulphur atom is attached with three very highly electronegative oxygen atoms. As a result, electrons are drawn towards oxygen atoms and S-atom remains wiht electron density and thus has the tendency to accept electrons. So it acts as a Lewis acid.
Today I came across the issue in Inorganic Chemistry by Dr.O.P.Tandon, 2007 edition, page 120.
It says
Molecules haivng a multiple bond between atoms of dissimilar electronegativity act as Lewis acids. Typical examples of molecules belonging to this class of Lewis acids are CO2, SO2 and SO3. Under the influence of attacking Lewis base, one π-electron pair will be shifted towardsmore negative atom.
In page 128 question (viii) is more direct.
So# has acidic behaviour. Explain
Hint:Sulphur atom is attached with three very highly electronegative oxygen atoms. As a result, electrons are drawn towards oxygen atoms and S-atom remains wiht electron density and thus has the tendency to accept electrons. So it acts as a Lewis acid.
Senin, 04 Februari 2008
IIT JEE Revision - Chemistry Ch 1. THE BASIC CONCEPTS - Core Points
JEE Syllabus
General topics:
The concept of atoms and molecules;
Dalton's atomic theory;
Mole concept;
Chemical formulae;
Balanced chemical equations;
Calculations (based on mole concept) involving common oxidation-reduction, neutralisation, and displacement reactions;
Concentration in terms of mole fraction, molarity, molality and normality.
---------
Stochiometric coefficients or numbers: The numbers which appear before the chemical symbols in a chemical equation.
Chemical equation gives information about moles of various reactants and products. Hence molar masses involved in the reaction and molar masses of products.
Mass percentage of substance in a system
Mole fraction of a substance in a system
Molarity = Amount of a substance (in mol)/Volume of solution expressed in dm^3
It is applicable to solutions only.
The unit of molarity is mol dm^-3. It is commonly abbreviated by the symbol M and is spelled as molar.
Molality = Amount of a a substance (in mol)/Mass of solvent expressed in kg
It is also applicable to solutions only
CONCEPT OF EQUIVALENT
__________________________
"One equivalent of a substance in a reaction is defined as the amount of substance which reacts or liberates 1 mol of electrons (or H^+ or OH^- ions).
General topics:
The concept of atoms and molecules;
Dalton's atomic theory;
Mole concept;
Chemical formulae;
Balanced chemical equations;
Calculations (based on mole concept) involving common oxidation-reduction, neutralisation, and displacement reactions;
Concentration in terms of mole fraction, molarity, molality and normality.
---------
Stochiometric coefficients or numbers: The numbers which appear before the chemical symbols in a chemical equation.
Chemical equation gives information about moles of various reactants and products. Hence molar masses involved in the reaction and molar masses of products.
Mass percentage of substance in a system
Mole fraction of a substance in a system
Molarity = Amount of a substance (in mol)/Volume of solution expressed in dm^3
It is applicable to solutions only.
The unit of molarity is mol dm^-3. It is commonly abbreviated by the symbol M and is spelled as molar.
Molality = Amount of a a substance (in mol)/Mass of solvent expressed in kg
It is also applicable to solutions only
CONCEPT OF EQUIVALENT
__________________________
"One equivalent of a substance in a reaction is defined as the amount of substance which reacts or liberates 1 mol of electrons (or H^+ or OH^- ions).
Atoms, Molecules and Atomic Theory Revision points
7. Dalton’s atomic theory
To provide theoretical justification to the laws of chemical combination which are experimentally verified, John Dalton postulated a simple theory of matter. The basic postulates of Dalton’s atomic theory are:
a. Matter is made up of extremely small indivisible and indestructible ultimate particles called atoms.
b. Atoms the same element are identical in all respects ie., in shape, size, mass and chemical properties.
c. Atoms of different elements are different in all respects and have different masses and chemical properties.
d. Atom is the smallest unit that takes part in chemical combinations.
d. Atoms of two or more elements combine in a simpler whole number ratio to form compound atoms (molecules).
e. Atoms can neither be created nor destroyed during any physical or chemical change.
f. Chemical reactions involve only combinations, separation or rearrangement of atoms.
Modern atomic theory
As a result of new discoveries made after Dalton developed his postulates, some modifications were done to atomic theory. They are:
1. Atom is no longer considered to be indivisible: It is found that atom is made up of subatomic particles such as electrons, protons and neutrons. We now state how many electrons are there, protons are there in an atom.
2. Atoms of same element may not be similar in all respects. Atoms of same elements have different atomic masses. These different atoms are called isotopes.
3. Atoms of different elements may have similar one or more properties. Atomic mass of calcium and argon (40 a.m.u.) are same. So the property of atomic mass is same for atoms of different elements. Isobars or elements or atoms having the same atomic mass.
4. Atom is the smallest unit which takes part in chemical reactions. Though electrons and protons are there, it is atom which takes part in chemical reactions and electrons exchange takes place between atoms.
5. The ratio in which the different atoms combine may be fixed and integral but may not always be simple. For example in sugar molecule the ratio of C,H and O atoms is 12:22:11, which is not simple.
6. Atom of one elements may be changed into atoms of other element. Transmutation is the process by which atoms one element can be changed inot elements of other elements by subjecting it to alpha rays.
7. The mass of atom can changed into energy. Mass and energy are inconvertible. The equation give for such conversion is E mc². Hence we cannot say that mass is not destructible. But in chemical reactions, atom remains unchanged and its mass is not destroyed to liberate energy.
Other topics to be covered
8.Avogadro’s hypothesis
9. atoms and molecules
10.Atomic and molecular masses
To provide theoretical justification to the laws of chemical combination which are experimentally verified, John Dalton postulated a simple theory of matter. The basic postulates of Dalton’s atomic theory are:
a. Matter is made up of extremely small indivisible and indestructible ultimate particles called atoms.
b. Atoms the same element are identical in all respects ie., in shape, size, mass and chemical properties.
c. Atoms of different elements are different in all respects and have different masses and chemical properties.
d. Atom is the smallest unit that takes part in chemical combinations.
d. Atoms of two or more elements combine in a simpler whole number ratio to form compound atoms (molecules).
e. Atoms can neither be created nor destroyed during any physical or chemical change.
f. Chemical reactions involve only combinations, separation or rearrangement of atoms.
Modern atomic theory
As a result of new discoveries made after Dalton developed his postulates, some modifications were done to atomic theory. They are:
1. Atom is no longer considered to be indivisible: It is found that atom is made up of subatomic particles such as electrons, protons and neutrons. We now state how many electrons are there, protons are there in an atom.
2. Atoms of same element may not be similar in all respects. Atoms of same elements have different atomic masses. These different atoms are called isotopes.
3. Atoms of different elements may have similar one or more properties. Atomic mass of calcium and argon (40 a.m.u.) are same. So the property of atomic mass is same for atoms of different elements. Isobars or elements or atoms having the same atomic mass.
4. Atom is the smallest unit which takes part in chemical reactions. Though electrons and protons are there, it is atom which takes part in chemical reactions and electrons exchange takes place between atoms.
5. The ratio in which the different atoms combine may be fixed and integral but may not always be simple. For example in sugar molecule the ratio of C,H and O atoms is 12:22:11, which is not simple.
6. Atom of one elements may be changed into atoms of other element. Transmutation is the process by which atoms one element can be changed inot elements of other elements by subjecting it to alpha rays.
7. The mass of atom can changed into energy. Mass and energy are inconvertible. The equation give for such conversion is E mc². Hence we cannot say that mass is not destructible. But in chemical reactions, atom remains unchanged and its mass is not destroyed to liberate energy.
Other topics to be covered
8.Avogadro’s hypothesis
9. atoms and molecules
10.Atomic and molecular masses
IIT JEE Revision - Laws of chemical combination
1 Importance of studying chemistry
2. Physical quantities and their S.I. units
3. Dimensional analysis
4. Measurement and significant figures
Accuracy
Accuracy is a measure of the difference between the true value (the value to be measured) and the value measured by an instrument.
Precision is depends totally on the instrument and it is the difference between measurements of the same dimension made number of times. It is expressed as the difference between one measurement and the arithmetic mean of the number of measurements.
Significant figures: Significant figures in a number are include all the certain digits plus one doubtful digit.
If a number has 4 significant figures or digits, it means 3 of them are certain and fourth one is doubtful.
Rules for determining the number of significant figures
1. All non-zero digits are significant
Decimal place does not determine the number of significant figures.
2. A zero becomes significant in case it comes between two non-zero numbers.
3. The zeros at the beginning of a number are not significant.
For example 0.0004 has only one significant figure.
4. All zeros placed to right of a number are significant. They represent the precision of the measuring scale.
For example 267.000 has six significant figures.
(The precision does not come by writing the number. It comes because the instrument has the ability to read a number certainly up to that level of measurement.)
Rules of calculations involving significant figures
Rule 1. The final result of addition or subtraction should be reported up to the same number of decimal places as are present in the term having the least number of decimal places.
Example- addition of three numbers
6.414
2.3
0.501
------
9.215 answer but the answer should be reported up to one decimal place only as 2.3 is the term having least number of decimal places.
Hence correct answer is 9.2
Rule 2. In multiplication or division, the final result should be reported up to the same number of significant figures as are present in the term with the least number of significant figures.
Example: 4.2345*1.25 = 5.293125
The final result should be reported up to three significant figures only as 1.25 has three significant figures. Hence the correct answer to be reported is 5.29.
Rounding off figures of retention of significant figures.
i) If the digit coming after the desired number of significant figures happens to be more than 5, the preceding digit or figure is increased by 1.
ii) If that digit is less than 5, it is neglected and hence the preceding significant figure remains unchanged.
iii) If that digit happens to be 5, the preceding digit is increased by one in case it is odd number. If preceding digit is an even number, it remains the same.
If the problem has number of steps, the rounding off is to be done at the final answer level only.
5. Chemical classification of matter
1. Element
Further classification: Metals, non-metals, metalloids
2. Compound
Further classification: Inorganic and organic
3. Mixture
Further classification: Homogeneous mixtures - they are called solutions.
Heterogeneous mixtures: They have visible boundaries of separation between the different constituents and they can be easily seen with naked eye.
6. Laws of chemical combination
a. Law of conservation of mass
During any physical o chemical change, the total mass of the products is equal to the total mass of reactants.
b. Law of constant proportions
A pure chemical compound always contains same elements combined together in the same definite proportion by weight.
c. Law of multiple proportions
When two elements combine to form two or more than two compounds, the weights of one of the elements which combine with a fixed weight of the other, bear a simple whole number ratio.
d. Law of reciprocal proportions
When two different elements combine separately with the same weight of a third element, the ratio in which they do so will be the same or some simple multiple of the ratio in which they combine with each other.
e. Gay Lussac’s law of combing volumes
Under similar conditions of temperature and pressure, whenever gases react together, the volumes of the reacting gases as well as products (if gases) bear a simple whole number ratio.
2. Physical quantities and their S.I. units
3. Dimensional analysis
4. Measurement and significant figures
Accuracy
Accuracy is a measure of the difference between the true value (the value to be measured) and the value measured by an instrument.
Precision is depends totally on the instrument and it is the difference between measurements of the same dimension made number of times. It is expressed as the difference between one measurement and the arithmetic mean of the number of measurements.
Significant figures: Significant figures in a number are include all the certain digits plus one doubtful digit.
If a number has 4 significant figures or digits, it means 3 of them are certain and fourth one is doubtful.
Rules for determining the number of significant figures
1. All non-zero digits are significant
Decimal place does not determine the number of significant figures.
2. A zero becomes significant in case it comes between two non-zero numbers.
3. The zeros at the beginning of a number are not significant.
For example 0.0004 has only one significant figure.
4. All zeros placed to right of a number are significant. They represent the precision of the measuring scale.
For example 267.000 has six significant figures.
(The precision does not come by writing the number. It comes because the instrument has the ability to read a number certainly up to that level of measurement.)
Rules of calculations involving significant figures
Rule 1. The final result of addition or subtraction should be reported up to the same number of decimal places as are present in the term having the least number of decimal places.
Example- addition of three numbers
6.414
2.3
0.501
------
9.215 answer but the answer should be reported up to one decimal place only as 2.3 is the term having least number of decimal places.
Hence correct answer is 9.2
Rule 2. In multiplication or division, the final result should be reported up to the same number of significant figures as are present in the term with the least number of significant figures.
Example: 4.2345*1.25 = 5.293125
The final result should be reported up to three significant figures only as 1.25 has three significant figures. Hence the correct answer to be reported is 5.29.
Rounding off figures of retention of significant figures.
i) If the digit coming after the desired number of significant figures happens to be more than 5, the preceding digit or figure is increased by 1.
ii) If that digit is less than 5, it is neglected and hence the preceding significant figure remains unchanged.
iii) If that digit happens to be 5, the preceding digit is increased by one in case it is odd number. If preceding digit is an even number, it remains the same.
If the problem has number of steps, the rounding off is to be done at the final answer level only.
5. Chemical classification of matter
1. Element
Further classification: Metals, non-metals, metalloids
2. Compound
Further classification: Inorganic and organic
3. Mixture
Further classification: Homogeneous mixtures - they are called solutions.
Heterogeneous mixtures: They have visible boundaries of separation between the different constituents and they can be easily seen with naked eye.
6. Laws of chemical combination
a. Law of conservation of mass
During any physical o chemical change, the total mass of the products is equal to the total mass of reactants.
b. Law of constant proportions
A pure chemical compound always contains same elements combined together in the same definite proportion by weight.
c. Law of multiple proportions
When two elements combine to form two or more than two compounds, the weights of one of the elements which combine with a fixed weight of the other, bear a simple whole number ratio.
d. Law of reciprocal proportions
When two different elements combine separately with the same weight of a third element, the ratio in which they do so will be the same or some simple multiple of the ratio in which they combine with each other.
e. Gay Lussac’s law of combing volumes
Under similar conditions of temperature and pressure, whenever gases react together, the volumes of the reacting gases as well as products (if gases) bear a simple whole number ratio.
Mole Concept - Revision Points
11. Mole concept
A mole is measuring unit like for example dozen.
A mole is a collection of 6.022*1023 particles
12. Mass-mole conversions
13. Percentage composition and molecular formula
Mole Concept - videos on Knol
A mole is measuring unit like for example dozen.
A mole is a collection of 6.022*1023 particles
12. Mass-mole conversions
13. Percentage composition and molecular formula
Mole Concept - videos on Knol
Solution Stoichiometry
Solution stoichiometry
In solution generally one component is present in lesser amount and is called solute.
The other present in excess is called the solvent.
The amount of solute present in a given quantity of solvent or solution is expressed in terms of concentration.
Stoichiometry of reactions in solutions
In solution generally one component is present in lesser amount and is called solute.
The other present in excess is called the solvent.
The amount of solute present in a given quantity of solvent or solution is expressed in terms of concentration.
Stoichiometry of reactions in solutions
Sabtu, 19 Januari 2008
IIT JEE Chemistry Ch 1. THE CONCEPTS - Core Points for Review
JEE Syllabus
General topics:
The concept of atoms and molecules;
Dalton's atomic theory;
Mole concept;
Chemical formulae;
Balanced chemical equations;
Calculations (based on mole concept) involving common oxidation-reduction, neutralisation, and displacement reactions;
Concentration in terms of mole fraction, molarity, molality and normality.
---------
Stochiometric coefficients or numbers: The numbers which appear before the chemical symbols in a chemical equation.
Chemical equation gives information about moles of various reactants and products. Hence molar masses involved in the reaction and molar masses of products.
Mass percentage of substance in a system
Mole fraction of a substance in a system
Molarity = Amount of a substance (in mol)/Volume of solution expressed in dm^3
It is applicable to solutions only.
The unit of molarity is mol dm^-3. It is commonly abbreviated by the symbol M and is spelled as molar.
Molality = Amount of a a substance (in mol)/Mass of solvent expressed in kg
It is also applicable to solutions only
CONCEPT OF EQUIVALENT
__________________________
"One equivalent of a substance in a reaction is defined as the amount of substance which reacts or liberates 1 mol of electrons (or H^+ or OH^- ions).
Some more points to be posted
General topics:
The concept of atoms and molecules;
Dalton's atomic theory;
Mole concept;
Chemical formulae;
Balanced chemical equations;
Calculations (based on mole concept) involving common oxidation-reduction, neutralisation, and displacement reactions;
Concentration in terms of mole fraction, molarity, molality and normality.
---------
Stochiometric coefficients or numbers: The numbers which appear before the chemical symbols in a chemical equation.
Chemical equation gives information about moles of various reactants and products. Hence molar masses involved in the reaction and molar masses of products.
Mass percentage of substance in a system
Mole fraction of a substance in a system
Molarity = Amount of a substance (in mol)/Volume of solution expressed in dm^3
It is applicable to solutions only.
The unit of molarity is mol dm^-3. It is commonly abbreviated by the symbol M and is spelled as molar.
Molality = Amount of a a substance (in mol)/Mass of solvent expressed in kg
It is also applicable to solutions only
CONCEPT OF EQUIVALENT
__________________________
"One equivalent of a substance in a reaction is defined as the amount of substance which reacts or liberates 1 mol of electrons (or H^+ or OH^- ions).
Some more points to be posted
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