Fundamentals of Chemistry PDF

INTRODUCTION As we Know that word science comes from latin word “Scientia” which means knowledge, This knowledge is based on hypothesis observation and experiments of universal science. In this universal sciences chemistry purely deals with the matter which have mass and occupy space. Even from...

INTRODUCTION As we Know that word science comes from latin word “Scientia” which means knowledge, This knowledge is based on hypothesis observation and experiments of universal science. In this universal sciences chemistry purely deals with the matter which have mass and occupy space. Even from the table salt we use in cooking to electro chemical interaction of our human brain show the differences of substance because of the composition, structure, properties and interaction of matter. The matter is undergoing changes continuously in nature as rusting of iron, evaporation of spirit and burning of coal are examples of reaction in which new substance are formed and energy is absorbed or released. All of these things are different due to the presence of different substances. Which are different by means of composition, properties, interaction , structure of matter. The chemists use chemistry to explain occurrence and description of things. They investigate material, their interactions and propose theories to illuminate our understanding from a particle to galaxies. | GAB HistORICAL BACKGROUND OF CHEMISTRY: Table 1.1 Time Chronology of Chemistry aetatere se Name _. of Scientists oo | Contribution/invention ig Origin of /Timeline scientist 2H,0,, Coefficients Liduid Gaseous State 1.5.2 Balancing of Chemical equation The chemical equation must be balanced in order to fulfill Law of conservation of mass. Mostly chemical equations can be balanced by inspection method (trial and error method). We can balance the equation by following steps. 1.Write the correct formula of all reactants on the left side and products on the Right side of an arrow. 2.Balance the number of atoms on each side. 3.If the number of atoms may appears more or less than other side, balance the equation by inspection method. Multiply the coefficient with formula to make the number of atoms same on the both (reactants and products) sides of equation. 4, The covalent molecules of hyderogen, nitrogen and chlorine exist as diatomic molecules. e.g H,, O,, N, and Cl,. We must write them as diatomic molecule rather than isolated atoms in chemical equation. 5. Finally check the equation to be sure that number and kind of atom are same on the reactant and product side. If yes now equation is balanced. For Example: Let us consider, in laboratory oxygen (O,) gas is prepared by heating potassium chlorate (KCIO,). The products are potassium chloride (KCI) and oxygen (O,) gas. Now balance the equation step wise. Step nol: Write correct formula of all reactants on left side and product on right side of an equation. KCIO, 4 —_ KCl, + O24 Step no2: Balance the number of atoms on each side. Reactants Products K (1) ————~> K (1) Cl (1) ——————» Cl (1) O (3) ——————>. 0 (2) We see that K and Cl elements have same number of atoms on both sides of equation but O is not balance because three atoms on reactant side and two atoms on product side. Step no3: Now multiply the formula (KCIO,) with co efficient 2 on reactant side and 3 in front of oxygen on product side to balance the oxygen atoms. 2KCIO, 4 KCl, + 30,4 Reactants Products K (2) —————_» K (1) Cl (2) ——————-» (Cl (1) O (6) —————— 0 (6) Step no4: Now again check and balance the equation by placing 2 in front of KCl on product side. 2KCIO,.. ————» 2KCl, + 30,,, Fundamentals of Chemis Reactants Products K (2) ————>_ K (2) Cl (2) ————> _ c1(2) O (6) ————> 0(6) Now this chemical equation is balanced. Test Yourself ® ~~ «Balance the following equation with coefficient 4 in front of KCIO, on reactant side and 4 in front of KCI on product side. KCIO3 «s) —— KCl + O2,) ~~ «Balance the following equation. CaCO, +HCl ——————> CaCl, +H,O +CO, | GE Mote AND AVOGADRO’S NUMBER 1.6.1 Gram Atomic Mass, Gram Molecular Mass, Gram Formula Mass As we have discussed before that all substances are made up of atoms, molecules or formula units. The mass of atom is atomic mass, mass of molecule is molecular mass and mass of formula unit is formula mass. All of these masses are expressed in a.m.u. When these masses are expressed in Gram they are termed as Gram atomic mass, Gram molecular mass and Gram formula mass. Gram Atomic Mass: The atomic mass of an element expressed in gram is called gram atomic mass. It is also called 1 mole. 1 gram atomic mass of oxygen = 16.00g = 1 mole of oxygen atom lgram atomic mass of carbon =12.00g = 1 moleofcarbonatom 1 gram atomic mass of nitrogen = 14.00g =1 moleof nitrogen atom Its means 1 gram atomic mass of different elements has different masses. Gram Molecular Mass: The molecular mass of an element or a compound expressed in gram is called gram molecular mass. It is also called 1 mole. 1 gram molecular mass of oxygen (O,) = 32.00g = 1 mole of oxygen molecule Tgram molecular mass of water (H,0) = 18.00g =1 mole of water 1 gram molecular mass of ethanol C,H;OH = 46.00g = 1 mole ofethanol  Fundamentals of Chemis Gram Formula Mass: The formula mass of an ionic compound expressed in grams is called gram formula mass. It is also called 1 mole. 1 gram formula of NaCl = 58.5g = 1 mole ofsodium chloride Tgram formula mass of CaCO, =100g =1 moleofcalciumcarbonate 1.6.2 Mole: The atomic mass, molecular mass and formula mass of a substance expressed in grams is known as mole. A mole is defined as “amount of substance containing particles equal to the avogadro's number 6.02 x 10”. Gram atomic mass and a.m.u Gram atomic J mass of | Atomic ™ mass of one carbon atom = 12g atom of C=12a.m.u Thus Gram Atomic mass of carbon is 12gram = 1 mole of carbon atom Gram Molecular mass of H,SO,is98gram = ImoleofH,SO, The relationship between mole and mass can be expressed as Given mass of a substance Number of moles = Molar mass of the substance Or Mass of substance ( gm) =Number of moles x Molar mass Example 1.5: Calculate the number of moles in 40g of Na. Solution Given mass of Na =40g Molecular mass of Na =23 a.m.u Number of moles =?. Given mass of a substance ber of moles = Number of moles Molar mass of the substance Number of moles of Na= _40 _ =1.73 moles of Na 23 Fundamentals of Chemis Example 1.6: What is the mass of 4 moles of CO,? Solution Number of moles of CO, = 4 moles Formula mass of CO, = 444.m.u mass of CO, =? Mass of CO, = number of moles of CO, X formula mass of CO, = 4x44=176gm 1.6.3 Avogadro’s Number Avogadro an Italian scientist, calculated the number of atoms, molecules or ions present in one mole. The value is found to be 6.02x10°. This value is represented by Ng and is called as Avogadro's number. Forexample: ImoleofO,molecule= 32g So 32gm of O, will contain 6.02x10” molecules Similarly 1 mole of NaCl =(234+ 35.5)= 58.5g of NaCl =6.02x10 Nd + 6.02x10°Ci Example 1.7: Calculate the number of atoms present in 9.2gm of Calcium (Ca). Solution: Atomic mass of Calcium (Ca) = 40 1g atomic weight of Calcium = 40gm AQg of Calcium contains =6.02x1 Oatoms of Calcium By using the formula Na x Given Mass in g Number of atoms = - Atomic mass Number of atoms = 6.02 x10x 10 9.2 = 1.384x10 atoms of Ca  PEER me ote Example 1.8: Calculate the number of moles, number of molecules present in 8g of C,H,,0,? Solution Molecular weight of glucose ( C, H,,0,) = (6x12) + (12x«1) + (6x16) =180 Given Mass of C,H,,O, = 8gm Number of moles = = =0.04 mole 80 Number of molecules = Number of moles x N, = 0.04 x 6.02 x10” = 0.240 x10” =2.40 x10” molecules of glucose Test Yourself &@ ~~ ~Prove that Avogadro's number is related to mole of any substance. ™ =§© Calculate the number of moles in 30gm of H;PO,. 14 CHEMICAL CALCULATIONS In all type of chemical calculations we calculate number of moles and number of particles of a substance. These calculations are based on mole. In the sequence of calculation first moles are calculated then number of particles. 1.7.1 Mole-Mass Calculation In this calculation we calculate number of moles of a substance with the help of following equation. Given mass of substance Number of Moles = Molar mass of substance We can calculate mass of a substance with the given moles of substance with following equation. Mass of substance= Number of moles x Molar Mass Fundamentals of Chemis Example 1.9: A coin of silver (Ag) having 8.5 gm weight. Calculate the number of moles of silver in coin? Solution The mass is converted to number of moles by the following equation: Given mass of substance Number of Moles = Molar mass of substance 8.5 107 = 0.07 moles of silver in 8.5 gm silver coin 1.7.2 Mole-Particle Calculation In this calculation we calculate number of moles of a substance in the given number of Particles (atom, molecules or formula unit). Given number of particles Given number of particles Number of Moles= = Avogadro's number 6.02x10° We can calculate number of particles as Number of particles = Number of moles x 6.02x10” Example 1.10: Calculate the number of moles and number of molecules present in 10gm of H,SO,? Solution The given mass of H,SO, = 10gm Molar mass of H,SO, = 98.0gm Gi f subst 10 Number of Moles of H, SO,= ee =0.10 mole Molar mass of substance 98 Number Of molecules = Number of moles x Avogadro’s number = 0.10 x 6.02x10° = 0.602 x10" = 6.02 x10 molecules of H,SO, in 10g. 1.7.3 Mole Volume Calculation The mole quantities of gases can be expressed in terms of volume, According to Avogadro, one gram mole of any gas at STP occupies volume of 22.4dm° (where standard temperature is O°C and standard pressures is 1 atm)  Fundamentals of Chemis Example 1.11: How many liters of carbon dioxide would be produced if 0.450 mole of carbon monoxide reacts with excess oxygen at STP. Solution: The equation for the reaction is 2CO (g) + O, (g) 2CO,(g) x, = 0.450 moles x, liters = ? 2 moles of CO 2 moles of Co, 5°, Step 1 9.450 —.— == x, —~ X 0.450x2 = —— == 0.450 2 2 2 moles 1 mole of gas at STP means 0°C temperature, 1 atm pressure and occupied volume 22.4dm’. Step2 Volume in litre/dm* = moles x 22.4dm°* = 0.45 x 22.4 = 10.08 litre of CO, So 10.08 liter of CO, would be produced when 0.450 mole of carbon monoxide reacts with excess oxygen at STP. ® Chemistry is the branch of science which deals with the properties, composition and Structure of matter. Chemistry also deals with the changes involved in the matter. ® Chemistry is everywhere in our environment and serving the humanity day and night. Due to its wide scope Chemistry is divided into physical chemistry, organic chemistry, inorganic chemistry, biochemistry, industrial chemistry, nuclear chemistry, environmental chemistry, analytical chemistry, medicinal chemistry, quantum chemistry, green chemistry. uw Matter is simply defined as anything that has mass and occupies Space.it is found in three common states solid, liquid and gas. The plasma is also considered as fourth state of matter. The different states of matter are due to difference of energy in increasing order. ® Matter is made up of smallest particles which are known as Atom. Atoms are the basic units of matter and define Structure of elements. Now it discovered that atoms are made up of three particles: protons, neutrons and electrons. = Amolecule is the smallest particle in a chemical element or Compound that has the chemical properties of that element or Compound. Molecules are made up of atoms that are held together by chemical bonds. These bonds form as a result of the Sharing or exchange of electrons among atoms. Molecules are Mono, di and poly atomic molecules. Fundamentals of Chemis ® A piece of matter in pure form is termed as a substance. Every substance has a fixed composition and specific properties. Every substance has physical and chemical properties. ® An Element is a substance made up of same type of atoms having same atomic number and cannot be decomposed into Simple substances by ordinary chemical reaction. ® Elements occur in nature in free or combined form in solid, Liquid and gases states. Now 118 elements have been discovered. ™ =Symbol formula is an abbreviation to represent the name of element. A symbol is taken from the name of that element in English, Latin and Greek. If it is one letter, it will be capital as H for Hydrogen, C for carbon, S for Sulphur and N for Nitrogen etc. in case of two letters symbol, only first letter is capital as Na for sodium, Cr for Chromium, He for Helium and Zn for Zinc. @ When two or more than two elements or compounds physically combined without any fixed ratio is known as Mixture. The component substances retain their chemical properties. Mixtures can be separated again by physical methods, as Filtration, Evaporation, Distillation and crystallization. ® The Atomic Number is number of protons present in the nucleus of atom of any Element. It is represented by symbol Z. All atoms of an element have same atomic number due to the presence of same number of protons. ® The Atomic Mass is sum of number of protons and neutrons present in the nucleus of atom of any element.it represented by symbol A and calculated by A=Z+n where n is number of neutrons. ® The atomic mass of an element expressed in gram is called gram atomic mass. It is also called 1 mole. ® The molecular mass of an element or a compound expressed in gram is called gram molecular mass. It is also called 1 mole. The formula mass of an ionic compound expressed in grams is called gram formula mass. It is also called 1 mole. ® The atomic mass, molecular mass and formula mass of a substance expressed in grams is known as mole. = Avogadro an Italian scientist, calculated the number of atoms, molecules or ions present in one mole. The value is found to be 6.02x10”. This value is represented by N, and is called as Avogadro's number. | SECTION- A: MULTIPLE CHOICE QUESTIONS Tick Mark (V) the correct answer 1. The branch of Chemistry which deals with hydrocarbons: (a) Industrial chemistry (b) Inorganic chemistry (c) Organic chemistry (d) Physical chemistry 2. The atomic mass of an element expressed in gram is: (a) Gram molecular mass (b) Gram atomic mass (c) Gram formula mass (d) Mole 3. Which of the following can be separated by physical means? (a) Mixture (b) Element (c) Compound (d) Substance 4 The molar mass of H,SO,is: (a) 98 a.m.u (b) 9.8gm (c) 98gm (d) 9.8 a.m.u 5. The Molecule consist of two atoms is : (a) Monoatomic molecule (b) Polyatomic molecule (c) Hetero atomic molecule (d) Di atomic molecule 6. A formula that indicates actual number and type of atoms in a molecule is called: (a) Chemical formula (b) Empirical formula (c) Molecular formula (d) Formula mass 7. Ethyl alcohol was prepared by: (a) Ibne-Sina (b) Al-Razi (c) Al-Beruni (d) Jaber bin-Hayan 8. which of the following is a homo atomic molecule: (a) H, (b) NH, (c) H,O (d) CO, Fundamentals of Chemis 9. The Empirical formula of hydrogen peroxide (H,O,) is: (a) HO, (b) HO (c) OH, (d) O,H, 10. A piece of matter in pure form is termed as: (a) Redical (b) Mixture (c) Compound (d) substance | SECTION- B: SHORT QUESTIONS: 1. Differentiate between the physical and analytical chemistry? 2. Write down the classification of molecule? 3. Identify the differences among the following: (a) Atom and lon (b) Molecule and Molecular ion (c) Compound and Mixture 4. Define the following terms: (a) Gram atomic mass (b) Gram molecular mass (c) Gram formula mass 5. Write down the empirical and molecular formula of the following? Sulphuric acid, Carbon dioxide, Glucose, Benzene 6. What is Free Radical? 7. Describe relationship between empirical and molecular formula? Explain with examples.. Explain why hydrogen and oxygen are considered as element whereas water is oo compound? | SECTION- C: DETAILED QUESTIONS: What do you mean chemical species, explain ion, molecular ion and free radical? > Write down the applications of chemistry in daily life? WN Explain in detail empirical and molecular formula? Explain the steps for balancing the equation? uk Name the branches of chemistry and discuss any five branches? | SECTION- D: Numerical (1) Balance the following equations by inspection method: (a) NH; +O, —____» NO + H,O (b) KNO,; ———> KNO, + O, (c) Ca +H,O + —W____» Ca(OH), + H, (d) NaHCO, ©§ ———————> Na,CO; + H,0 + CO, (e)CO +O, —————> CO, (2) Calculate the formula mass (a.m.u) of the following? Al,O; , MgCl, , NaCl , KNO, (3) Calculate the molecular mass (a.m.u) of the following? C,H,OH, HO, NH,, CO, (4) How many moles are present in 40 gm of H,SO,? (5) Calculate the number of moles and number of molecules present in the following? (a) 16g of H,CO, (b) 20g of C.H,,0,  “>, ATOMIC STRUCTURE Time Allocation Teaching periods =14 Assessment period = Major Concepts Weightage =14 2.1 Discovery of Sub Atomic Particles, electron, proton and neutron. 2.2 Theories and Experiments Related to Atomic Structure. 2.3 Modern Theories of Atomic Structure. 2.4 Electronic Configuration. 2.5 Isotopes and their common application. STUDENTS LEARNING OUT COMES (SLO'S) Students will be able to: © Describe the discovery of electron, proton and neutron. © Define Atomic Number (Z) and Mass Number (A) in term of number of proton and/or neutron. © Describe the contributions Rutherford made to the development of the atomic theory. © Explain how Bohr's atomic model is different. © Define Modern theories of Atomic Structure( De Broglie Hypothesis & Schrodinger atomic model) © Describe the presence of sub shells in a shell. © Distinguish between Shells and Sub shells. © Write Electronic Configuration of the first 18 Elements in the Periodic Table. © Define and compare isotopes of an Atom. © Discuss the properties of the isotopes of the H, C, Cl and U. © Draw the structure of different isotopes from mass number and atomic number. © State the importance and uses of the isotopes in various fields of life. The word atom is derived from a Greek word ATOMOS means indivisible, which was first describe by Greek philosopher Democritus. Democritus beleived that all matter consist of very small indivisible particles which are known as atoms. Johan Dalton an English school teacher and chemist suggested the fundamental atomic theory, which explains that all elements are made up of tiny indivisible particles called atoms. Dalton assumed that no particles smaller than atom Fig 2.1 Democritus exist, but by the passage of time new experiments showed that atom is composed of even smaller particles which are known as sub-atomic particles. After that these sub-atomic particles were discovered and named as electron, proton and neutron. We will discuss all these discoveries in this chapter. Dalton’s atomic theory explains the chemical nature of matter and existence of indivisible atoms, but at the end of 19” century sub-atomic particles were Fig 2.2 john Dalton discovered by different scientists. First sub-atomic particle Electron was discovered by M. Farady, William Crooks and J.J. Thomson, second sub-atomic particle Proton was identified by Goldstein and Ernest Rutherford, while third sub-atomic particle Neutron was revealed by Chadwick. All of these findings were milestone in the knowledge of atomic structure which we have now. Electron is the lightest particle carrying negative charge in an atom discovered by J.J.Thomson and William crooks. Fig 2.3 Chadwick  Atomic Structure Fig 2.4 J.J. Thomson Fig 2.5 William Crooks Fig 2.6 M.Faraday The apparatus used for this type of experiment is called discharge tube which consists of glass tube fitted with two metal electrodes connected to a high voltage source and a vacuum pump. Discharge tube inside is evacuated, and electrodes are connected with high voltage source at very low pressure(1mm of Hg), when the high voltage current start passing between electrodes then a streak of bluish light originate and travel in straight line from cathode (-ve electrode) to anode(+ve electrode), Which cause glow at the wall of opposite end. These rays are called cathode rays. Discovery of Electrons Discharge Tube Air at very low presure NN | Green glow _ __—_ _ — | ——_—————_> ——_————_> Cathode —_ Anode SE \— To vacuum pump eee High voltage Generator Production of cathode rays Fig 2.7 William Crooks Discharge Tube J.J. Thomson justified that these rays were deflected towards positive plate in electric and magnetic field which shows that these rays possess negative charge due to this negative charge, particle was named Electron.These electrons were obtained from the cathode and when cathode material was changed the same phenomenon was observed which proves that electrons are constituent of all matter.  Atomic Structure Properties of Cathode Rays (Electrons) 1. They travel in straight line from cathode towards Anode. 2. They produce sharp shadow of an opaque object placed in their path. 3. They have negative charge and bend towards positive plate in electric and magnetic field. 4. These rays when strike with glass or other material and cause the material to glow. 5. The charge to mass ratio (e/m) of cathode particles is 1.7588x10°coulomb per gram. This is same for all electrons, regardless of any gas in discharge tube. 6. They can produce mechanical pressure indicating they possess kinetic energy (K.E). 2.1.2 Discovery of Protons The Proton is positively charged particle discovered by Goldstein in 1886. J.J. Thomson investigated properties of proton in 1897. Protons were observed in same apparatus of cathode rays tube but with perforated cathode. Goldstein discovered that not only negatively charged cathode rays but positively charged rays are moving in opposite direction through perforated cathode. These positive rays passes through the holes of cathode, where they strike with walls of tube and cause the glow of tube. Fig 2.8 Goldstein These rays were named as Canal rays (protons). Discovery of Protons Air at very Red low pressure Glow Discharge = tube Perforated on = {] Anode cathode | High voltage —_~ cele L generator To pan Fig 2.9 Gold Stein Discharge Tube  Atomic Structure Remember that canal rays are not emitted by anode, but they are result of striking of electron with residual gas molecules in discharge tube. Electrons ionize the gas molecules as follows. Mte—>M"4+2e Goldstein justified that atoms are electrically neutral, while electrons carry negative charge. It mean for each electron there must be one equivalent positive charge to neutralize that electron. This particle is called proton and it is a fundamental particle of all Atoms. Properties of Canal Rays (Protons) 1. They travel in straight line towards Cathode. 2. They produce sharp shadow of object placed in their path. 3. They have positive charge and bend towards negative plate in electric and magnetic field. 4. The charge to mass ratio (e/m) of positive particles is much smaller than electron. It varies according to nature of gas present in tube. 5. The mass of proton is 1836 times more than electron. 2.1.3 Discovery of Neutrons In 1920 Rutherford predicted that atom must possess another neutral particle with equivalent mass of proton. Different scientists started working on this neutral particle. later on, in 1932 Chadwick successfully discovered Neutron. Chadwick found that when alpha (c)particles bombarded on Beryllium plate some penetrating radiations were given out. Chadwick suggested that these radiations were due to material particle with mass comparable to hydrogen atom but have no charge. These radiations (particle) are called Neutron. It can be expressed in equation as follows. ‘Be + 2 He ————— 4 6 ‘C+ 0 The neutron is fundamental part of an Atom, present inside nucleus with proton and is included in atomic mass. Properties of Neutrons 1. The Neutrons are neutral particles. 2 They have no charge. 3. The mass of neutron is almost equal to that of proton. 4 These particles are most penetrating in matter.  Atomic Structure 2.1.4 How Atomic Number (Z) and Mass Number (A) are related with number of proton and neutron As we discussed in discovery of fundamental particles of an atom, that Atom consist of three particles Electron, Proton and Neutron. But if all atoms have same fundamental particles then why the atoms of one element are different from the atoms of another element? For example: How does an atom of Carbon (C) is different from an atom of Nitrogen (N)?Because all atoms can be identified by their number of protons they contain. Therefore no two elements have the same number of protons. Atomic Number (Z) The number of protons inside the nucleus of an atom is called Atomic Number. Atomic number is represented by Z. The elements are identified by their atomic number. Different elements have different atomic numbers because of different number of protons. In neutral atoms number of protons are equal to number of electrons, so the atomic number also indicate total number of electrons outside the nucleus. For example atomic number of Carbon(C) is 6. It mean that each carbon atom has 6 protons and 6 electrons in it. Atomic number= Z = Number of proton in nucleus = Total number of electron around nucleus Atomic number (Z) is written as subscript on the left hand side of the chemical symbol e.g