Basic Chemistry

Chapter 2 - Basic Chemistry

1. CHAPTER 2 BASIC CHEMISTRY

2. WHY ARE WE REVIEWING CHEMISTRY?

3. WE ARE REVIEWING CHEMISTRY BECAUSE: your entire body is made up of chemicals chemical processes underlie all body processes the food you eat, the medicines you take, it’s all chemistry!

4. CHEMISTRY IS… chemistry : the science that deals with the composition and properties of substances and various elementary forms of matter. biochemistry : the chemistry of living material

5. Concepts of matter and energy matter : anything that has mass and takes up space it is the “stuff” of the universe chemistry studies the nature of matter

6. THREE STATES OF MATTER three main states of matter 1. solid – definite shape, definite volume 2. liquid – no definite shape, definite volume (fits to the size of its container) 3. gas – no definite shape, no definite volume (expands to fill available space)

7. THREE STATES OF BODY MATTER Bodily examples: 1. solid – bones, teeth 2. liquid – blood, urine 3. gas – air, digestive byproducts

8. elements Element : substances that cannot be broken down into simpler substances Can you name some examples? (Please say yes!)

9. Periodic table A complete listing of all the elements appears in the Periodic Table It is called periodic because it repeats The modern Periodic Table was developed in 1869 by a Russian scientist named Dimitri Mendeleev

10. Periodic table

11. Periodic table basics A vertical column is called a group or a family These groups usually contain the same number of valence electrons A horizontal row is called is called a period or a series These periods show similarities in ionization and activation energy

12. Periodic table basics On the left hand side are the metals Usually solid, shiny, good conductors of heat and electricity On the right hand side are the non-metals Usually gaseous, dull, poor conductors of heat and electricity In the diagonal space between metals and non-metals are the metalloids Some characteristics of both metals and non-metals

13. Ok, so now how to read this thing

14. READING THE PERIODIC TABLE Review: (fingers crossed here) All elements are made up of only one type of atom Atom : the smallest part of an element, indivisible by normal chemical means

15. Subatomic particles Every atom is composed of three types of subatomic particles: 1. Protons (P + ) positively charged, found in the nucleus, has mass 2. Neutrons (N ) neutrally charged, found in the nucleus, has mass 3. Electrons (E - ) negatively charged, found outside the nucleus, had negligible mass

16. Reading the periodic table The Chemical/Elemental Name of the element is given The abbreviated symbol related to the name of the element is called the Chemical/Elemental symbol

17. Reading the periodic table The atomic number is the number of electrons And in a balanced atom, the number of electrons is equal to the number of protons Think here, - = + means no charge!

18. Reading the periodic table Then the atomic mass is equal to the mass of the nucleus (protons + neutrons) Remember, neutrons add mass but have no charge!

19. Number of neutrons To find the number of neutrons all you must do is: Atomic mass – atomic number (protons + neutrons) – protons = neutrons Easy!

20. So when you read this: You should be able to tell me the chemical symbol, chemical name, atomic mass, atomic number, number of protons, neutrons and electrons.

21. Periodic table – round 2 Ok, so now that you are experts (or at least not clueless) let’s try so advanced uses of the Periodic Table

22. Valence electrons Electrons exist outside the nucleus of the atom and move continuously They are negatively charged and are always pulled towards the positively charged nucleus But they do this at different locations

23. Valence electrons Electron shells or energy levels : the regions in which electrons travel Each shell can only hold a certain number of electrons The outer most level is called the valence level and the electrons in that level are called valence electrons

24. Valence electrons – electron levels In English, Level 1 = 2 Level 2 = 8 Level 3 = 18 Level 4 = 32 That’s all I will make you learn for now

25. diagrams Because electrons are not stationary it is important to show where they are generally located In order to do this we can used either a Bohr Diagram or a Lewis Diagram (Dot Diagram)

26. Bohr diagrams Bohr Diagrams show ALL electrons in their correct energy levels Let’s look at Oxygen:

27. Bohr diagram Now try Neon on your own. Not Neon

28. Bohr diagram Does your diagram look something like this?

29. Lewis diagram Now on the other hand, a Lewis Diagram (also called a Dot Diagram) only shows the VALENCE electrons

30. Lewis diagram Now try Chlorine on your own

31. Lewis diagram Let’s hope yours looks like this:

32. isotopes Isotopes: atoms of the same elements with a different number of neutrons Therefore, they have a different atomic mass The mass changes but the charge does not!

33. isotopes Because isotopes have the same number of electrons their chemical properties are the same They have the same reactivity and bonding ability

34. Isotopes - radioisotopes Radioisotopes: the heavier isotopes of certain atoms are unstable and tend to decompose (to become more stable) Radioactivity: the spontaneous decay of radioisotopes The most commonly used radioisotope is C 13

35. Isotopes - radioisotopes Radioisotopes are used in minute amounts to tag biological molecules so that they can be followed throughout the body Valuable for medical diagnosis and treatment

36. PET SCANS http://www.youtube.com/watch?v=WFqqVpPzUaI

37. MATTER – PHYSICAL CHANGE matter may be changed both physically and chemically physical changes do not alter the basic nature of a substance ex. melting, contraction of the muscles, blood vessel contraction

38. MATTER - CHEMICAL CHANGE chemical changes do alter the composition of the substance ex. burning, fermenting, lactic acid production, hormone release

39. MATTER CHANGES

40. ENERGY energy : the ability to do work massless and does not take up space

41. ENERGY kinetic energy : energy of motion potential energy : inactive or stored energy all forms of energy exhibit both kinetic and potential work capacities

42. ENERGY Remember! All living things are made or matter and all living things require a continuous supply of energy

43. FORMS OF ENERGY 1. Chemical Energy 2. Electrical Energy 3. Mechanical Energy 4. Radiant Energy

44. 1. Chemical energy is stored in the bonds of chemical substances when the bonds are broken, the potential energy is unleashed and becomes kinetic energy ex. car engine (internal combustion engine)

45. 2. Electrical energy results from the movement of charged particles in the house, electrical energy is the flow through your wiring

46. 2. Electrical energy in your body, an electrical current is generated when charged particles (ion) move across cell membranes the nervous system uses electrical currents called nerve impulses to transmit messages from one part of the body to another

47. 3. Mechanical energy energy directly involved in moving matter as the muscles in your legs shorten, they pull on your bones, causing your limbs to move

48. 4. Radiant energy travels in waves the energy of the electromagnetic spectrum this includes x rays, infrared radiation, visible light, radio, uv rays

49. Energy form conversions with a few exceptions, energy is easily converted from one form to another

50. Energy form conversions in the body, chemical energy of foods is trapped in the bonds of a high-energy chemical called ATP (Adenosine TriPhosphate ) ATP’s energy may ultimately be transformed into the electrical energy of a nerve impulse or mechanical energy of shortening muscles

51. Energy form conversions Energy conversions are inefficient some of the energy supply is always “lost” to heat

52. Energy form conversions it is not really lost but rather unusuable Remember, energy is neither created nor destroyed, it only changed form for example, when matter is heated, the particles move more quickly (their kinetic energy increases)

53. ORGanic compounds THE BUILDING BLOCKS - MACROMOLECULES

54. Organic compounds Organic compounds : Molecules that contain atoms of Carbon, Hydrogen and usually Oxygen High energy molecules, it takes energy to make them The ability to use energy to make or synthesize organic compounds is an important characteristic of all living things

55. Organic compounds On their own, organic compounds would break down, releasing energy Organisms are able to control this breakdown in order to harness the energy released Most organic compounds belong to one of four main groups: Carbohydrates, Proteins, Lipids, Nucleic Acids

56. CARBOHYDRATES (SUGARS AND STARCHES) Carbohydrates are composed mainly of just the basic elements of other organic molecules: carbon, hydrogen, and oxygen monomer: monosaccharides , polysaccharides Simplest one is glucose

57. CARBOHYDRATES Most complex sugars are formed from a chain of simple sugars Starches and more complex sugars consist of very long chains that may include more than just simple sugars

58. CARBOHYDRATES Some carbs are structural molecules which provide support and protection Ex. Chitin and cellulose Healthy carbs are naturally occurring sugars Unhealthy carbs are refined, added simple and complex sugars kCals only, no nutritional value

59. PROTEINS Made up of amino acids - 20 different a.a . Monomer: amino acids Enzymes : proteins that speed up or catalyze, specific chemical reactions All enzymes are proteins but all proteins are not enzymes work in enzyme-substrate complex enzyme is the “lock” substrate is the “key”

60. PROTEINS Without enzymes, most metabolic reactions would proceed very slowly or not at all Ex. Lipases break down lipids (fats) Some hormones are proteins Ex. Insulin Hormones: chemicals that act as messengers to help different parts of the body to work together

61. PROTEINS Four stages of Protein Folding 1. Amino Acid strand - disulfide bridges 2. A helix or B pleated sheets 3. Tertiary folding - hydrogen bonding, more disulfide bridging within the same molecule 4. Quaternary structure, multiple tertiary structures joining together

62. PROTEINS

63. PROTEINS Humans can synthesize 11 of 20 a.a . required for protein synthesis - “non-essential a.a .” Remaining 9 - “essential a.a .” must be included in diet

64. LIPIDS (FATS, OILS, WAXES) Monomers: Glycerol molecule bonded to 3 fatty acid molecules Lipids are often used for energy storage, helping form membranes, and waterproofing surfaces

65. lipids Some hormones are fats Ex. Steroid hormones

66. lipids Saturated Fats - “bad” fats no “kinks” in the chain, able to pack together Unsaturated Fats Polyunsaturated fats and monounsaturated fats - “good” fats “kinks” allow fats to stay free

67. NUCLEIC ACIDS Nucleic acids store and transmit the basic genetic information of all living things Monomer: nucleotides Nucleotides consist of a simple sugar joined to molecules containing phosphorus and nitrogen

68. NUCLEIC ACIDS One type of nucleic acid is DNA (Deoxyribonucleic Acid) DNA specifies all the instructions for an organism’s construction and maintenance

69. Nucleic acids Genome : An organism’s complete genetic information The 4 nitrogenous bases of the nucleotides are: Adenine, Cytosine, Thymine, and Guanine Nitrogenous bases are like letters in a word, and genes are like complete “words” in a sentence

70. NUCLEIC ACIDS RNA – Ribonucleic Acid Uracil instead of Thymine Many RNA molecules help convert the genetic info contained in DNA into proteins - protein synthesis Some RNAs catalyze reactions like enzymes

71. MOLECULES AND COMPOUNDS When two or more atoms combine chemically molecules are formed For example, when two Nitrogen atoms bond, a molecules of Nitrogen gas is formed N + N -> N 2

72. MOLECULES AND COMPOUNDS In the Nitrogen example the reactants are the substances involved in the chemical reaction (the single Nitrogen atoms) The product is the substance that results from the reaction (the Nitrogen molecule)

73. MOLECULES AND COMPOUNDS A Molecular formula shows the chemical composition or atomic makeup of a molecule What chemicals are in NaCl ? Bonus points if you know what this is!

74. MOLECULES AND COMPOUNDS When two or more different atoms bond together to form a molecule, the molecule is called a compound For example 2H + O -> H 2 O Thus a molecule of water is a compound

75. MOLECULES AND COMPOUNDS It is important to remember that compounds have properties different from those of the elements of which they are composed

76. CHEMICAL BONDS AND CHEMICAL REACTIONS Chemical reactions : when two or more atoms combine with or dissociate from each other

77. CHEMICAL BONDS AND CHEMICAL REACTIONS A chemical bond is an energy relationship Bonds are directly related to the number of valence electrons and the electron levels

78. Chemical bonds – the importance of electrons Remember, electrons occupy generally fixed regions of space around the nucleus called electron shells or energy levels The electrons closest to the nucleus are the most strongly attracted and those farther from the nucleus are less securely held

79. CHEMICAL BONDS – VALENCE ELECTRONS The only electrons that are important when considering bonding behavior are those in the valence level When the valence level has 8 electrons, the atom is completely stable and is chemically inactive (inert)

80. CHEMICAL BONDS – VALENCE ELECTRONS When the valence shell contains fewer than 8 electrons, an atom will tend to gain, lose or share electrons to reach a stable level

81. TYPES OF CHEMICAL BOND 1. Ionic Bonds 2. Covalent Bonds 3. Hydrogen Bonds

82. Ionic bonds Ionic Bond : A chemical bond formed when electrons are completely transferred from one atom to another

83. Ionic bonds Atoms are electrically neutral, but when they gain or lose electrons during bonding, their positive and negative charges are no longer balanced This creates ions or charged particles

84. IONIC BONDS Polyatomic ions : Ions composed of multiple atoms Ex. Ammonium NH 4 +

85. Ionic bonds - anions Anions : negatively charged ions that result from the addition of an electron

86. Ionic bonds - cations Cation : a positively charged ion that results from the loss of an electron

87. Ionic bonds Both anions and cations result when an ionic bond forms Because opposite charges attract, the newly created ions tend to stay together Ex. Sodium chloride (Table Salt)

88. Ionic bonds - salts Salts : are ionic compounds that result from the neutralization of an acid and a base They are composed of a cation and an anion so the resulting product is neutral

89. COVALENT BONDS Electrons do not need to be completely gained or lost for atoms to become stable Covalent molecules : molecules in which atoms share electrons Covalent bonds: bonds resulting from a shared pair of electrons (co = with, valent = having power)

90. COVALENT BONDS Ex. formation of diatomic gases

91. COVALENT BONDS – nonpolar molecules Molecules in which the electrons are shared equally are called nonpolar covalently bonded molecules

92. Covalent bonds – polar molecules When the electron pairs are not equally shared, the result is a polar molecule (A molecule with two poles)

93. hydrogen bonds Hydrogen bonds: extremely weak bonds formed when a Hydrogen atom bound to one electron-hungry atom is attracted by another electron-hungry atom (Nitrogen or Oxygen are good examples of electron-hungry atoms) Forms a “bridge”

94. Hydrogen bonds Hydrogen bonds are also important intramolecular bonds They help binds different parts of the same molecule together They are fragile but very important in helping maintain the structure of protein molecules

95. Patterns of chemical reactions Synthesis reactions Decomposition reactions Exchange reactions

96. Synthesis reactions Synthesis reactions : when two or more atoms or molecules combine to form a larger, more complex molecules

97. Synthesis reactions Always involve bond formation Energy must be absorbed to make bonds Underlie all anabolic (constructive) activities in body cells Important in growth and tissue repair

98. Decomposition reactions Decomposition reactions : when a molecule is broken down into smaller molecules, atoms or ions

99. Decomposition reactions Synthesis reactions in reverse Bonds are always broken Chemical energy is released Underlie all catabolic (destructive) processes in body cells Molecule-degrading reactions Ex. food digestion and glycogen breakdown

100. Exchange reactions Exchange reactions : reactions that involve both synthesis and decomposition reactions

101. Exchange reactions Bond are both made and broken A switch is made between molecule parts and different molecules are formed

102. reactions Remember! Regardless of the type of reaction, most chemical reactions are reversible. Also temperature, particle size, concentration of particles and catalyst presence influence the rate of chemical reactions