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Aim: What are the basic parts of chemistry?

Aim: What are the basic parts of chemistry?

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Aim: What are the basic parts of chemistry?

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  1. Aim: What are the basic parts of chemistry? Do Now: What is a compound? Homework: Read pages 156-160 & Answer Questions (1-4) on pg. 160 do all vocab on pg. 156

  2. Chemistry The Study of Matter

  3. Three Classes of Matter 1. Elements the most basic types of matter 2. Compounds 2 or more elements bonded together in definite proportion 3. Mixtures two or more substances (elements and or compounds) physically combined, but not chemically bonded

  4. Elements • basic types of matter that can not ordinarily be broken down into simpler substances • How many are found in nature? 92 • Which ones are normally present in humans? 26

  5. Aim: What are the basic parts of chemistry? Do Now: How can we figure the number of protons, neurtons, and electrons? Homework: Castle Learning assignment #4 and Quiz Thursday

  6. Important Elements In Organisms Hydrogen (H) Oxygen (O) Carbon (C) Nitrogen (N) Calcium (Ca) Phosphorous (P) Potassium (K) Sulfur (S) Sodium (Na) Chlorine (Cl) Magnesium (Mg) Iodine (I) Iron (Fe) 13 others = 0.1% • 96% of your body mass is made up of : CHON • O (65%) + C (18%) + H (10%) + N (3%)

  7. Examples of Elements: Periodic Table

  8. Atoms • the smallest particles of an element • contain protons, electrons and neutrons 1. Protons: charge = +1 mass = 1 AMU (atomic mass unit) location: in nucleus (center) of atom

  9. 2. Electrons: charge = -1 mass = almost 0 location = orbiting outside the nucleus 3. Neutrons charge = 0 mass = 1 AMU location = in nucleus (center) of atom

  10. The Structure of an Atom

  11. Properties of Atoms 1. Electrically neutral total charge = 0, because: # electrons = # protons 2. Atomic Number • refers to the number of protons in the nucleus of the atom • determines behavior & type of element 3. Atomic Mass Number # of protons + # of neutrons

  12. What is the atomic # of carbon? What is the atomic mass number of oxygen? What would happen to the electrical charge of these atoms if an electron were removed?

  13. Finding the Contents of an Atom from Atomic # & Atomic Mass # • # of protons = atomic number • # of electrons = atomic number • # of neutrons = atomic mass # - atomic number

  14. Forces That Hold Atoms Together Electrical Force • opposite charges attract • electrons (-) orbit around nucleus because the nucleus is positive (+) Nuclear Force • holds the protons and neutrons together within the nucleus • overcomes repulsion of + charged protons

  15. What is the number of protons, neutrons, and electrons? • Electrons = 9 • Protons = 9 • Neutrons = 10

  16. What is the number of protons, neutrons, and electrons? • Electrons = 16 • Protons = 16 • Neutrons = 16

  17. Aim: What are are isotopes & how can we benefit by using them? Do Now: Write a paragraph on chemistry that contains these words: Electrons, Neutrons, atoms, elements, compounds, protons, atomic mass, atomic number, nucleus, and orbital's. Homework: Finish protons, neutrons, and electrons worksheet Quiz Tomorrow

  18. Isotopes • atoms with the same atomic number but different atomic masses • atoms of the same element with different numbers of neutrons • isotopes of oxygen (atomic number = 8) • O – 16 contains: 8 protons, 8 electrons, 8 neutrons • O – 18 contains: 8 protons, 8 electrons, 10 neutrons

  19. Examples of Isotopes

  20. Uses for Isotopes • Researchers use isotopes as “tracers” to distinguish between different sources of the same element Example: • In photosynthesis: carbon dioxide & water  glucose & oxygen gas • If plant receives carbon dioxide with O-16 and water with O-18, it will release molecules of oxygen gas containing 0-18 • Conclusion: The oxygen gas comes from water molecules notcarbon dioxide

  21. Radioisotopes • contain so many neutrons that they are unstable • release particles or “radiation” and are called “radioactive” • can be damaging to cells • lose their radioactivity at a fixed rate • the “half life” of a radioisotope is the amount of time it takes for 50% of the atoms to lose their radioactivity • location be easily detected and visualized because of their radioactivity

  22. How can these isotopes be useful?

  23. Uses for Radioisotopes • Used to: • kill cancer cells • “trace” atoms from one compound to another within organisms (Carbon-14 is frequently used this way) • visualize internal organs • find the age of fossils and other materials

  24. Images of the Thyroid Gland Using Radioactive Iodine

  25. Aim: How are chemical bonds formed? Do Now: What do you think the word “bond” means? Homework: Study for tomorrow’s Quiz (Chemical Bonding)

  26. Chemical Bonds • bind atoms together • involve sharing or transfer of electrons Two basic types of chemical bonds 1. Ionic Bonds • electrons are transferredfrom one atom to another • creates charged particles calledions • when atoms lose electrons they become: positive ions • negative ions are produced when atoms: gain electrons

  27. Ionic bond - NaCl (animation).mov

  28. 2. Covalent Bonds • electrons are shared by two different atoms • electrons will now orbit around both nuclei • produce “molecules” • a molecule is a distinct group of two or more atoms held together by covalent bonds (or the smallest unit of a compound)

  29. Covalent bond - H2O (animation).mov

  30. Ionic vs. Covalent Bonds

  31. Two types of covalent bonds • Non-polar covalent • electrons are shared equally by two different atoms • bonds between two atoms of the same element are always non-polar covalent • bonds between C and H are also non- polar

  32. 2. Polar Covalent Bonds • electrons are shared unequally because one atom exerts a greater attraction • creates a “polar molecule” which contains positive and negative areas • covalent bonds between atoms of two different elements are usually polar

  33. Does this show a non-polar or a polar covalent bond?

  34. Water: a polar molecule • electrons are sharedunequally between H & O • O has 8 protons, H has only 1 • shared electrons are more attracted to:_____ Answer: oxygen • The area of the molecule containing oxygen will be __________, while the areas containing hydrogen will be ___________ Answers: negative, positive

  35. What causes water molecules to stick to each other?

  36. Compounds • Two or more elements joined together by chemical bonds • The properties of a compound are very different from the properties of the individual elements it contains • The ratio of elements within a compound is fixed and is indicated by it’s chemical formula • The smallest unit of a covalently bonded compound is a molecule

  37. Aim: How do we determine the pH of a solution? Do Now: Prepare for Basic Chemistry Quiz. Homework: Complete Lab

  38. What type of charge do electrons have? • What would make an atom electrically neutral? • The type of bond that transfers electrons is known as a(n) ___________ bond. • The nucleus of an atom contains both ____________ & ___________. 5. How is the atomic number of an atom determined?

  39. Elements that have the same atomic number, but a different atomic mass are known as _____________. • What part of the atom is gained or lost? • Charged particles are known as ______. • Water is considered to have a (non-polar or polar) covalent bond because electrons are unequally shared. 10. How would an atom gain a positive charge?

  40. Acids, Bases and Neutral Solutions

  41. Ionization of Water • ionization means the release of ions (charged particles) from a compound • less than O.01% of water molecules ionize H2O  H+ and OH- • H+ is a “hydrogen ion”, it was a hydrogen atom before it lost an electron • OH- is a “hydroxide ion”, it gained an extra electron when H+ was released from water • Pure water is a neutral solution because the number of H+ is equal to the number of OH-

  42. Acids Compounds that release hydrogen ions(H+) when they are added to water • Examples: (don’t memorize) 1. Hydrochloric acid (HCl) HCl  H+ and Cl- 2. Carbonic acid: (H2CO3) H2CO3  H+ and HCO3- 3. Nitric acid: (HNO3) HNO3  H+ and NO3-

  43. Bases (alkali) compounds that absorb hydrogen ions or release hydroxide ions (OHֿ) • Examples: (don’t memorize) 1. Sodium hydroxide (NaOH): NaOH  Na+ and OH- 2. Potassium hydroxide (KOH) KOH  K+ and OH-

  44. Acidic, Basic & Neutral Solutions • Acidic solution: H+ > OH- • Basic solution: H+ < OH- • Neutral solution: H+ = OH-

  45. Acid Base Indicators 1.Red Litmus Paper indicates bases by turning blue 2. Blue Litmus Paper indicates acids by turning red 3. Bromothymol yellow in acids, green near neutral and blue in bases 4. pH paper • turns various colors to indicate acids, neutral solutions and bases • can also indicate the strength of an acid or base

  46. Acid-Base Indicators

  47. pH scale - based on the concentration of hydrogen ions in a solution - used to indicate the strength of acids and bases - ranges from 0 to 14 - acids have pH’s < 7, bases have pH’s > 7 - neutral solutions have a pH of 7 - the farther from 7 the greater the strength of the acid or base • based on powers of 10 - each decrease of 1 digit on the pH scale means 10 times as many hydrogen ions

  48. Questions about pH • How would you describe solutions with the following pH’s? 2? 8? 6? 13? 7? • As pH increases, H+ concentration _____ • As pH decreases, acidity ________ • The H+ concentration in a pH of : • 2 is _____________greater than a pH of 4 • 3 is _____________greater than a pH of 7 • 1 is _____________greater than a pH of 4

  49. Aim: 1. What are mixtures? 2. What are 3 types of formulas used to describe compounds? Do Now: 1. Take out lab. 2. Compare covalent & ionic bonds to each other. Homework: Study for tomorrow’s quiz on Basic Chemistry.