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Matter –Anything that has mass and occupies space

Matter –Anything that has mass and occupies space. 1 The basic unit of matter is called the atom. Figure 2-2 Isotopes of Carbon. Section 2-1. 2, 3 Atomic Nuclei contain protons and neutrons. Protons 1+ charge size 1 amu nucleus Neutrons 0 charge size 1 amu in nucleus

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Matter –Anything that has mass and occupies space

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  1. Matter –Anything that has mass and occupies space • 1 The basic unit of matter is called the atom.

  2. Figure 2-2 Isotopes of Carbon Section 2-1 • 2, 3 Atomic Nuclei contain protons and neutrons. • Protons 1+ charge size 1 amu nucleus • Neutrons 0 charge size 1 amu in nucleus • Electrons 1- charge size 1/1840 amu in electron cloud Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14 6 electrons 6 protons 7 neutrons 6 electrons 6 protons 6 neutrons 6 electrons 6 protons 8 neutrons

  3. 4 Atoms are neutral because they contain the same # of electrons & protons.

  4. 5 Chemical elements are groups of atoms having the same atomic number, that is, atoms having the same number protons. These are all atoms of Carbon. All have atomic # 6.

  5. An Element in the Periodic Table Section 2-1 6 • 6. Proton # = 6 : shown by the atomic number • Also, C atoms have 6 electrons: Since atoms are neutral, if you know proton #, you also know electron #! C 12.011

  6. Figure 2-2 Isotopes of Carbon Section 2-1 • 7 Isotopes are forms of the same element that have the same number of protons but a different number of neutrons. Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14 6 electrons 6 protons 7 neutrons 6 electrons 6 protons 6 neutrons 6 electrons 6 protons 8 neutrons

  7. Figure 2-2 Isotopes of Carbon Section 2-1 • Isotopes are identified by isotopic notation: • Carbon-12, carbon-13, carbon-14 OR • 12C 13C 14C • 6 6 6 Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14 6 electrons 6 protons 7 neutrons 6 electrons 6 protons 6 neutrons 6 electrons 6 protons 8 neutrons

  8. 9 Isotopes of the same element have the same properties because they have the same atomic number (the same number protons) • 12C13C14C • 6 6 6

  9. 10 Chemical compounds are groups of atoms held together by chemical bonds. Chemical compounds are more stable than individual atoms (except for noble gas atoms which have stable ---filled—valence electron shells. • Chemical compounds allow atoms to obey the “octet rule”. (2 electrons in the outer electron shell in H and He, but 8 for other elements.

  10. 11 Chemical formulas show the numbers of different kinds of atoms bonded together in a single formula unit of a compound • NaCl one Na ion bonded to one Cl ion • Why do we know it’s composed of ions? Because Na is a metal—an electron donor—and Cl is a nonmetal—an electron acceptor if a metal is present to give it an electron.

  11. 12 Atoms in compounds are held together by chemical bonds—either ionic or covalent.

  12. Figure 2-3 Ionic Bonding 13 Ionic bonds: attraction of negative ions to positive ions because a metal donates its electrons to a nonmetal atom, forming stable ions with complete valence shell octets. Section 2-1 Sodium ion (Na+) Chloride ion (Cl-) Sodium atom (Na) Chlorine atom (Cl) Transfer of electron Protons +11 Electrons -11 Charge 0 Protons +17 Electrons -17 Charge 0 Protons +11 Electrons -10 Charge +1 Protons +17 Electrons -18 Charge -1

  13. 13 Covalent bonds form when nonmetal atoms share electrons to fill their valence octets, linking atoms because both nuclei attract the shared electrons.

  14. Figure 2-3 Ionic Bonding 14 Ions are atoms carrying a charge after losing or gaining valence electrons. Section 2-1 Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+) Chloride ion (Cl-) Transfer of electron Protons +17 Electrons -18 Charge -1 Protons +11 Electrons -11 Charge 0 Protons +11 Electrons -10 Charge +1 Protons +17 Electrons -17 Charge 0

  15. 15. False. Atom that loses electrons becomes a positive ion.

  16. 16 Molecules (Not ionic compounds!) form when atoms are joined with covalent bonds.

  17. 17 A is false—2 shared electrons is a single covalent bond A C b D covalent bonds are formed when atoms share electrons http://academic.brooklyn.cuny.edu/biology/bio4fv/page/covalent_bonds.html

  18. 18 Van Der Waals forces and dipole-dipole interactions hold atoms of nearby molecules together. • Occasionally, valence electrons are nearer one atom than the other in a covalent bond, creating areas partial charge. http://www.chem.unsw.edu.au/coursenotes/CHEM1/nonunipass/HainesIMF/images/dipoledipole.jpg

  19. Lesson 3: Chapter 2 The chemistry of Life • Watch movie on water, then answer questions on the worksheet together in your lab group BEFORE beginning the lab. Teacher will select one worksheet for grading, by random drawing. • Complete water lab, then turn in one copy per lab group . Teacher will select one student’s report. • Discuss the water movie & labs, and complete the 2.2 guided reading questions 1—8 as a class. • Homework: guided reading & study workbook questions, pages 15—16, #9—21.

  20. Section Outline Section 2-2 • 2–2 • Properties of Water, • the strangest and most important molecule on earth! http://www.wsi.nrcs.usda.gov/products/images/wq_drop.jpg

  21. http://www.sumanasinc.com/webcontent/animations/content/propertiesofwater/water.htmlhttp://www.sumanasinc.com/webcontent/animations/content/propertiesofwater/water.html Watch this movie from beginning to end. Then, the teacher will advance the movie one question at a time, giving time for you to write the answers to each question.

  22. Guided reading & study workbook for section 2.2, p 15--161. Water molecules contain 10 electrons, 1 for each H and eight for O. Water molecules also contain 10 protonsTrue or False. Water molecules are neutral. • True • False

  23. 2. Because water molecules have O at one end and H at the other, the entire molecule: • Is positively charged • Is negatively charged • Is polar, with partial + & - charges.

  24. 3. Water is a polar covalent molecule because: • More electronegative O atoms are bonded to less electronegative H atoms • O carries a δ- charge & H’s a δ+ charge • The shared electrons of each O—H covalent bond are more strongly attracted to the O • All of the above • None of the above

  25. Strongest triple covalent bond • 2nd strongest double covalent bond • 3rd strongest single covalent bond • 4th strongest ionic bond • 5th strongest Hydrogen bonds • 6th strongest Dipole dipole interactions (polar molecules attracted δ+ to δ- ) OTHER than Hydrogen bonds • 7th strongest Van der Waals forces (hydrophobic • interactions of nonpolar compounds)

  26. 4. Which statement is True? • Hydrogen bonds are stronger than ionic bonds. • Attraction of the H in one water molecule to O in another is a Hydrogen bond • Hydrogen bonds are stronger than covalent bonds • Hydrogen bonds are the strongest bonds BETWEEN different neutral molecules. • Choices 2 and 5 are true

  27. cohesion

  28. 5. Cohesion is: • Attraction of δ+ and δ- atoms of water molecules to atoms or ions of other substances, like the glass in a graduated cylinder • Attraction of δ+ H and δ- O of water molecules atoms in adjacent water molecules

  29. 5. Adhesion (exhibited by water adhering to the spider web) is: • Attraction of δ+ and δ- atoms of water molecules to atoms or ions of other substances, like the glass in a graduated cylinder • Attraction of δ+ H and δ- O of water molecules atoms in adjacent water molecules

  30. 6. Water is cohesive (shown by water’s forming droplets)because: • δ+ H and δ- O atoms of water molecules are attracted to each other in the same molecule • δ+ H and δ- O atoms of water molecules are attracted to each other in adjacent molecules

  31. Surface tension versus capillary action

  32. 7. The rise of water in a narrow tube (like water rising in a thermometer) against the force of gravity is: • surface tension • capillary action • specific heat

  33. 8 In plants capillary action: • Draws water upwards from the roots into the leaves through thin tubes called xylem • Pulls sugar downwards from the leaves into the roots through thin tubes called phloem

  34. 10-1-09 Lesson on solutions and suspensions with homework correction slides Lesson on acids and bases Complete water labs & questions & acid/base questions. Tear off lab & questions through end page. Put rest back in notebooks. Homework: prep for a quiz on ch 2.1,2.2, tomorrow

  35. Mixture: 2 or more substances combined but not chemically bonded. They can be separated without another chemical reaction (a physical separation). e.g., sand and water can be separated with a filter inks in markers can be separated with chromatography Salt can be removed from water by evaporating the water

  36. 9. True or False. Sucrose (C6H12O6) is a mixture. • True • False

  37. 9. True or False. Sucrose (C6H12O6) dissolved in water is a mixture. • True • False

  38. Mixtures may be heterogenous (nonuniform throughout) or homogenous (uniform throughout) Another name for a homogeneous mixture is solution. Another name for a heterogeneous mixture is suspension.

  39. 10. This picture shows bananas mashed up in water. This mixture is a • suspension • solution

  40. 11. World’s greatest solvent: water! • Water is known as the universal solvent because it can dissolve ionic compounds and polar covalent compounds. • Ionic and polar covalent compounds are hydrophillic (water loving) • Water can not dissolve nonpolar covalent compounds. • Nonpolar compounds are hydrophobic (water hating)

  41. 12. A suspension is a: • Homogeneous mixture • Heterogeneous mixture • Unstable (particles settle out over time) • Stable (a solution whose solutes do not settle out) • 2 and 3

  42. Parts of Solutions: Solvent: more abundant—does the dissolving Solute: less abundant—gets dissolved

  43. 13. Two liters water are mixed with 0.3 liters salt. The water is the • solution • solute • solvent

  44. 14. Two liters water are mixed with 0.3 liters salt. The salt is the • solution • solute • solvent

  45. concentration Molarity (M) = # moles solute/#L solution 3 Moles/0.5 L = 6 M 1 mole NaCl = 58.4 g 29.2 g/0.25 L = 0.5 moles/0.25 L= 2M

  46. Aqueous solutions can be neutral, acidic, or basic. These descriptions depend refer to the behavior of the solute when it is dissolved in water and to how this behavior alters the molar concentrations of these two ions in the aqueous solution: H+ protons OH1- hydroxide ions

  47. 1 out of over 500 million water molecules dissociates to H+ hydronium, OH- hydroxide Neutral aqueous solutions and pure water contain equal numbers of both ions. 2H2O(l) → H3O+(aq) + OH–(aq)

  48. 14. Two water molecules can react to form: • Nonpolar compounds • Hydronium & hydroxide ions 2H2O(l) → H3O+(aq) + OH–(aq)

  49. 15. Water is neutral because it: • Is polar covalent • Forms Hydrogen bonds • Has equal numbers of hydronium & hydroxide ions • Is nonpolar covalent

  50. Acids increase the H1+content of water in aqueous solutions. Bases increase the OH1- HCl  H+ + Cl- NaOH Na1+ + OH1-

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