Foundation and fundamentals of chemistry ppt

Importance and Scope of Chemistry

1. Good Afternoon & Namaste General and Physical Chemistry UNIT ONE Presented By TEJ NARAYAN CHAPAGAIN KALIKA MANAVGYAN SECONDARY SCHOOL, BUTWAL, NEPAL 10/16/2020 1 TEJ NARAYAN CHAPAGAIN(TNC)

2. INTRODUCTION TO CHEMISTRY Chemistry is a branch of science which deals with the study of composition , structure, properties , transformations ,and application of matter. Chemist study, discover , reproduce ,and apply the principles of chemistry for invention and innovation of better and more efficient ideas, technologies, processes, and products for the welfare of life and society. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 2

3. WHAT DOES CHEMISTRY? Chemistry contributes a way of understanding the natural phenomena, traces out the complications and confers the idea of solution. Chemistry has played an important role in the life of mankind including the fields of clothing, shelter, pharmacy, agriculture, food, polymer, explosives, drying,etc . 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 3

4. Chemistry As A Central Science Chemistry is often regarded as central science as it links with other disciplines like biology, physics, geology, meteorology, environmental science, material science, medical science, engineering etc. Coming up to the 21 st century, it has been an era of technology. Nano technology has emerged as an interdisciplinary field of science and engineering to introduce smart materials which is mainly guided by the basic principles of chemistry. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 4

5. Evaluation W ritten exam(theory) + Practical Exam Theory covers 75 marks Practical covers 25 marks Total 100 marks Question pattern L.q 20Marks = 2/4 questions 10X2=20 S.q 25Marks = 5/7 question 5x5 =25 V.s.q 30Marks = 15/22 question 2x15=30 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 5

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8. Foundation and Fundamentals General introduction of chemistry Importance and scope of chemistry Basic concepts of chemistry (atoms, molecules, relative masses of atoms and molecules, atomic mass unit ( amu ), radicals, molecular formula, empirical formula ) Percentage composition from molecular formula 10/16/2020 8 TEJ NARAYAN CHAPAGAIN(TNC)

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10. General introduction of chemistry T he branch of science concerned with the substances of which matter is composed, the investigation of their properties and reactions, and the use of such reactions to form new substances . Chemistry is the scientific discipline involved with elements and compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a reaction with other substances. 10/16/2020 10 TEJ NARAYAN CHAPAGAIN(TNC)

11. What is this? 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 11

12. WHAT IS CHEMISTRY Chemistry is the branch of science which deals with the changes that takes place when atoms or molecules after interaction undergo transformation from one form to the another. The chemical properties of the substances are determined through experiments where physical properties such as pressure, volume, temperature, concentration , density, time etc., involve the recording of the a pure number which represents the following ratio. Pure number= Value of physical quantity/Value of unit physical quantity 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 12

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23. Branches of chemistry 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 23

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25. Importance of chemistry 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 25

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29. Scope of chemistry Importance and Scope of Chemistry There are many instances in your day-to-day life that involves chemistry, its applications, and its rules. Let us look at them one by one. 1) Supply of Food The study of chemistry provided the world with chemical fertilizers such as urea, calcium superphosphate, sodium nitrate, and Ammonium Sulphate . These chemicals have helped greatly in increasing the yield of fruits, vegetables, and other crops. Thus, we can cater to the ever-growing demand for food. It has helped to protect the crops from insects and harmful bacteria by the use of certain effective insecticides, fungicides, and pesticides. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 29

30. Chemistry also led to the discovery of preservatives. These chemicals have greatly helped to preserve food products for a longer period. It has given methods to test the presence of adulterants. This ensures the supply of pure foodstuff. 2) Contribution to Improved Health and Sanitation Facilities Chemistry provided mankind with a large number of life-saving drugs. We could find a cure for dysentery and pneumonia due to the discovery of sulphur drugs and penicillin. Besides this, life-saving drugs like cisplatin and taxol are effective for cancer therapy and AZT is used for AIDS victim. Some of the common drugs that chemistry has blessed us with include: 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 30

31. Analgesics : To reduce the pain of different types. Antibiotics : To   cure infection and cure diseases. Tranquillisers : To reduce tension and bring about calm and peace to patients suffering from mental diseases. Antiseptics : To stop infection of the wounds. Disinfectants:  To kill the microorganism present in toilets, floor, and drains. Discovery of  anaesthetics  has made surgical operations more and more successful. The use of  insecticides  such as DDT and Gammexane has greatly reduced the dangers of diseases caused by the rats, mosquitoes, and flies. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 31

32. 3. The Scope of Chemistry in Saving the Environment Thanks to science, now we have environment-friendly chemicals that help us conserve the nature. One such example is the replacement of CFCs in the refrigerators. 4.Increase in Comfort, Pleasure, and Luxuries Because of the advancements in science and the discoveries of chemistry, we lead a more comfortable life today. You may ask how? Let us see below. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 32

33. 4) Increase in Comfort, Pleasure, and Luxuries Because of the advancements in science and the discoveries of chemistry, we lead a more comfortable life today. You may ask how? Let us see below. Synthetic fibres :  These are more attractive, comfortable and durable. The include  terylene , nylon, and rayon. They are easy to wash, dry quickly and do not need ironing. Chemistry provides a large number of synthetic dyes which imparts bright and fast colour to the clothes. Building materials : By supplying steel and cement, chemistry helps in the construction of safer homes and multi-storage buildings. It also helps in the construction of long-lasting and durable dams and bridges. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 33

34. Supply of metals:  Metals like gold, silver, copper, iron, aluminium , zinc and a large number of the alloys are used for making various objects. These include ornaments, utensils, coins, and many Industrial and agricultural implements. Articles of domestic use : Chemistry has made our homes more comfortable by supplying a large number of articles of domestic uses. Examples include detergents, oils, and fats, sugar, paper, glass, plastic, paints, cosmetics, perfumes, cooking gas etc. We are able to beat the heat in summers by using refrigerants like ammonia, liquid sulphur dioxide, and freon . Entertainment:  Cinema, video cameras, simple cameras make use of films which are made of Celluloid and coated with suitable chemicals. Fireworks which amuses us on festival and marriages are chemical products. Can you imagine how boring life would have been if you wouldn’t have been able to take all those cute selfies ? 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 34

35. Transport and communication : All means of transport use either petrol or diesel or coal which are all chemical products. Nuclear atomic energy:  Chemistry has come to the rescue by providing an alternative source of energy which is nuclear energy. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 35

36. 5) The Scope of Chemistry in Industry Chemistry plays an important and useful role towards the development and growth of a number of industries. This includes industries like glass, cement, paper, textile, leather, dye etc. We also see huge applications of chemistry in industries like paints, pigments, petroleum, sugar, plastics, Pharmaceuticals. It has also helped in the greater production of  sulphuric acid, nitric acid, and Ammonia, hydrogenated oils by providing suitable catalysts. 6) The Scope of Chemistry in Wa r Chemistry plays an important role in the discovery of highly explosive substances such as TNT, nitroglycerine, and dynamite. It also plays a role in finding poisonous gases like mustard gas, Phosgene etc. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 36

37. Q : List down some problems caused by Chemistry in our society. Ans : Nuclear energy is useful but the disposal of nuclear waste poses a serious problem to humanity. Phonograph records have added to our pleasure for listening to music but they are made of polyvinyl chloride. This is produced from vinyl chloride which can cause liver cancer in industrial workers. Antibiotics have eliminated infectious diseases but the overuse is very harmful. Chemistry has given drugs like LSD, cocaine, brown sugar. These prove to be a curse to the society. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 37

38. Home Assignment 1. What are the uses of chemistry? 2. Is chemistry important in life? 3. Why Is chemistry important for medicine? 4. What is chemistry and its uses? 5.How is chemistry used in medicine? 6.Is chemistry important to become a doctor? 7.Do doctors use chemistry? 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 38

39. 8.How is chemistry related to health? 9.What are basics of chemistry? 10.What are the characteristics of chemistry? 11.What are the fields of chemistry? 12.What are three reasons for studying chemistry? 13.What is the future of chemistry ? 14.What is the role of chemistry in technology? 15.Will Chemists be needed in the future? 16.Who is chemistry father? 17.What exactly is chemistry? 18.What is full form chemistry? 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 39

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42. What are the uses of chemistry? Chemistry plays an important and useful role towards the development and growth of a number of industries. This includes industries like  glass , cement, paper, textile, leather, dye etc. We also see huge applications of chemistry in industries like paints, pigments, petroleum, sugar, plastics, Pharmaceuticals. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 42

43. Is chemistry important in life? Chemistry  is  important  in everyday  life  because: ... Many of the changes you observe in the world around you are caused by  chemical  reactions. Examples include leaves changing colors, cooking food and getting yourself clean. Knowing some  chemistry  can help you make day-to-day decisions that affect your  life 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 43

44. Why Is chemistry important for medicine? Chemistry  in  Medicine Major contributions to health care have been made by  chemistry . The development of new drugs involves  chemical  analysis and synthesis of new compounds. ... The  chemistry  of the disease must be studied, as well as how the drug affects the human body. A drug may work well in animals, but not in humans 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 44

45. What is chemistry and its uses? Article Contents.  Chemistry , the science that deals with the properties, composition, and structure of substances (defined as elements and compounds), the transformations they undergo, and the energy that is released or absorbed during these processes 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 45

46. Basic concepts of chemistry(contents) atoms, molecules, relative masses of atoms and molecules, atomic mass unit ( amu ), radicals, molecular formula, empirical formula Percentage composition from molecular formula 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 46

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48. Structure of matter Matter consist of large number of extremely small particles which may be either atoms or molecules. Molecules are further made up of atoms. So ,the ultimate particle of any element or compound is atom. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 48

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50. Atom An atom is the smallest particle of an element which can take part in chemical reaction. Atom may or may not have independent existence. The term atom was proposed by John Dalton. Atoms are defined as  “the basic building blocks of matter” . 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 50

51. Test your self Atoms of inert gases like helium, argon , neon etc have ………………..existence whereas atoms of hydrogen , oxygen , nitrogen etc do not have independent existence. Atom was considered to be the ultimate particle of ……………. Which can not be further subdivided into smaller particles. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 51

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53. Structure of atom An atom includes a nucleus, and then a series of orbital circles that surround this nucleus similar to the solar system structure. The protons and the neutrons reside in the nucleus. The electrons are in the orbitals . The amount of protons in the nucleus of an atom determines its atomic number. Hydrogen and helium are examples of elements that have an atom. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 53

54. About atom Atom consist of positively charged nucleus around which negatively charged particles(electron) revolve like planet round the sun. The nucleus contains positively charged proton and chargeless neutrons. These particles are combinely called nucleons. The mass of atom is mainly due to nucleus. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 54

55. Size of atom The atom is about 10 -10  meters (or 10 -8  centimeters) in size. This means a row of 10 8  (or 100,000,000) atoms would stretch a centimeter, about the size of your fingernail. Atoms of different elements are different sizes, but 10 -10  m can be thought of as a rough value for any atom.  10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 55

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57. Dalton’s atomic theory All matter consists of indivisible particles called atoms. Atoms of the same element are similar in shape and mass, but differ from the atoms of other elements. Atoms cannot be created or destroyed. Atoms of different elements may combine with each other in a fixed, simple, whole number ratios to form compound atoms. Atoms of same element can combine in more than one ratio to form two or more compounds. The atom is the smallest unit of matter that can take part in a chemical reaction. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 57

58. Drawbacks of Dalton's Atomic Theory The indivisibility of an atom was proved wrong: an atom can be further subdivided into protons, neutrons and electrons. However an atom is the smallest particle that takes part in chemical reactions. According to Dalton, the atoms of same element are similar in all respects. However, atoms of some elements vary in their masses and densities. These atoms of different masses are called isotopes. For example, chlorine has two isotopes with mass numbers 35 and 37. . 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 58

59. Contd …. Dalton also claimed that atoms of different elements are different in all respects. This has been proven wrong in certain cases: argon and calcium atoms each have an atomic mass of 40 amu . These atoms are known as isobars. According to Dalton, atoms of different elements combine in simple whole number ratios to form compounds. This is not observed in complex organic compounds like sugar (C 12 H 22 O 11 ). The theory fails to explain the existence of allotropes; it does not account for differences in properties of charcoal, graphite, diamond 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 59

60. Merits of Dalton's Atomic Theory The atomic theory explains the laws of chemical combination (the Law of Constant Composition and the Law of Multiple Proportions). Dalton was the first person to recognize a workable distinction between the fundamental particle of an element (atom) and that of a compound (molecule). 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 60

61. Assignment What are 5 postulates of Dalton's atomic theory? What is Daltons atomic theory? What are the limitations of Dalton atomic theory? Does atom size increase across a period? What is difference between atom and molecule? 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 61

62. Assignment What is the relation between atom and molecule? How many atoms are in a molecule? Which atom is largest in size? What is an atom? What are atoms made of? 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 62

63. PROJECT WORK Dear students you are given a project work that is to be submitted as a part of internal evalution of grade 11. Observe in your surroundings (kitchen, school, shop, etc.) and make a possible list of organic and inorganic compounds. How are they different? Why is it necessary to study them separately, put your argument? Last date of submission : 2077/7/30 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 63

64. ROLE OF CHEMISTRY IN COMMUNITY 1.Manufacture of glass ,cement, fertilizers,dyes,drugs,metal,oil,fuel,paper,pesticides used in daily life. 2. Invention of explosives,rocket fuels,biochemical weapons,bombs etc 3. Analysis of soil,water,,examination of crime and frauds,etc 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 64

65. MOLECULE The smallest particle of an element or compound having independent existence is called a molecules. For example, i ) H 2 O represents one molecule of the compound water ii) Cl 2 represents one molecule of the element chlorine. Classifiaction of molecules 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 65

66. Monoatomic atomic molecule- It consists of only one atom. Example- Noble gases (He, Ne, Ar , Kr, Xe ), Metals (Na, Fe, etc) Diatomic molecule- it consist of only two atoms of same or different chemical elements. Example- i ) two atom of same element(H 2 ,O 2 ,N 2 , etc) ii) two atom of different element(CO,NO ) Polyatomic molecule- It consist of three or more atoms held together by covalent bond. It further classfied into homonuclear and heteronuclear molecule. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 66

67. Homonuclear molecule- it consist of atoms of same element. H 2 -Diatomic molecule O 3 -triatomic molecule P 4 -tetraatomic molecule S 8 -Octaatomic molecule b) Heteronuclear molecule- it consist of atoms of different elements. H 2 O, NH 3 , CO 2 , CH 4 etc 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 67

68. Definition of atomic mass Atomic mass of an element is the number of parts by weight of that element which shows how many times the element is heavier than1/12 th weight of one atom of C-12 isotope. It is denoted by A and its unit is amu (atomic mass unit). therefore, A= wt.of an element 1/12 part of C-12 isotope 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 68

69. Atomic mass unit Mass of one atom of C-12 is assigned 12 amu . One- twelth (1/12 th ) of mass of one atom of C-12 is called 1amu. Now, 1 mol of C-12=12g or, mass of 6.023x10 23 carbon atoms=12g mass of 1 carbon atom=12/ 6.023x10 23 mass of 1/12 carbon atom=1.66x10 -24 g ∴1amu=1.66x10 -24 g=1.66x10 -27 kg This is called absolute mass of 1 amu . 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 69

70. Fractional atomic mass The same element has different isotopes. The percentage abundance of each isotope in nature is different. Atomic weight is not the weight of single isotopes. It is calculated by taking the average weight of different isotopes of an element according to their percentage abundance in nature. Therefore , atomic mass is found in fractional number. For example, Chlorine exist as two isotopic forms Cl-35(75%) and Cl-37(25%). At.WT = 35X75 +37X25 = 35.5amu 100 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 70

71. Explain mass number is always whole number but atomic weight is not whole number. Mass number is sum of number of protons and neutrons present at the nucleus and it is whole number. But, atomic wt. is calculated by taking the average wt. of different isotopes of element according to their percentage abundance in nature and it is fractional. For example: mass number of Mg= 12n+12p= 24 But atomic mass of chlorine is calculated by taking the average mass of Cl-35(75%) and Cl-37(25%) At.WT = 35X75 +37X25 = 35.5amu 100 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 71

72. Question for practice 1.The element Ag consists of two isotopes: Ag-107 with natural abundance of 51.83% and Ag-109 with natural abundance of 48.17%. Calculate the relative atomic mass of Ag. 2. The average atomic mass of hydrogen is 1.008 amu . Calculate the percentage abundances by mass of protium and deuterium in the natural mixture of hydrogen. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 72

73. Molecular mass It is defined as the number which shows how many times the molecule is heavier than 1/12 th weight of one atom of C-12 isotopes. Its unit is amu . i.e. molecular mass= wt. of molecule 1/12 part of C-12 isotope 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 73

74. Ionic mass It is defined as the number which shows how many times the ion is heavier than 1/12 th weight of one atom of C-12 isotopes. Its unit is amu . i.e. ionic mass = wt. of ion 1/12 part of C-12 isotope Eg . Mass of Ca ++ is 40 mass of NH4 + is =NX1+Hx4=14+4=18 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 74

75. Ions or radicals Atom or group of atoms having charge are called ions. Eg - Na + , CO 3 2- ,OH - Cl - etc The ions having positive charge are called cations and the ions having negative charge are called anons . Eg - Na + is cation , Cl - is anion The cation of salt are called basic radicals( parent base) and the anions of the salt are called acid radicals( Parent acid) . Eg . Na + is basic radical while Cl - is acid radical. 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 75

76. Test question 1.Write two examples of each for monovalent anions,trivalent cations and monovalent cations . 2.Write two examples of each for divalent anions,trivalent anions and trivalent cations . 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 76

77. Chemical formula- Symbolic representation of a molecule or ion of a substance is called chemical formula. For example, H 2 O is the formula of water Types of chemical formula- Molecular Formula-  Definition:  An expression which states the number and type of atoms present in a molecule of a substance. Examples:  There are 6 C atoms and 14 H atoms in a hexane molecule, which has a molecular formula of C 6 H 14 . 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 77

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80. Empirical formula mass The sum of mass of all atoms present in empirical formula is called empirical formula mass. For eg , empirical formula mass of CH 2 O =12+1X2+16 = 30 amu . Calculation of common factor(n) n= molecular mass Empirical formula mass 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 80

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82. Percentage composition The percentage of individual atoms of a given number of moles of molecule, is called percentage composition. % composition = wt. of individual atom X100% molecular wt. of molecule Q.1. calculate the percentage composition of each element in sodium thiosulphate (Na 2 S 2 O 3 ). 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 82

83. Assignment What is meant by saying that atomic mass of calcium is 40 ? How many atoms are in 1g of calcium ? How many atoms are in 40g of calcium ? How many atoms are in 1g of oxygen ? How many atoms are in 1g of sodium? 10/16/2020 TEJ NARAYAN CHAPAGAIN(TNC) 83

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