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Section Outline Section 2-1 • 2–1 The Nature of Matter A. Atoms B. Elements and Isotopes 1. Isotopes 2. Radioactive Isotopes C. Chemical Compounds D. Chemical Bonds 1. Ionic Bonds 2. Covalent Bonds 3. Van der Waals Forces Go to Section: Matter –Anything that has mass and occupies space •1 The basic unit of matter is called the atom. Go to Section: Figure 2-2 Isotopes of Carbon Section 2-1 Nonradioactive carbon-12 6 electrons 6 protons 6 neutrons Nonradioactive carbon-13 6 electrons 6 protons 7 neutrons Radioactive carbon-14 6 electrons 6 protons 8 neutrons •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 Go to Section: 4 Atoms are neutral because they contain the same # of electrons & protons. Go to Section: 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. Go to Section: An Element in the Periodic Table Section 2-1 6 C 12.011 •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 #! Go to Section: Figure 2-2 Isotopes of Carbon Section 2-1 Nonradioactive carbon-12 6 electrons 6 protons 6 neutrons Nonradioactive carbon-13 6 electrons 6 protons 7 neutrons Radioactive carbon-14 6 electrons 6 protons 8 neutrons •7 Isotopes are forms of the same element that have the same number of protons but a different number of neutrons. Go to Section: Figure 2-2 Isotopes of Carbon Section 2-1 Nonradioactive carbon-12 6 electrons 6 protons 6 neutrons Nonradioactive carbon-13 6 electrons 6 protons 7 neutrons Radioactive carbon-14 6 electrons 6 protons 8 neutrons 8 Isotopes are identified by isotopic notation: • Carbon-12, carbon-13, carbon-14 OR 13C 14C • 12C 6 6 • 6 Go to Section: 9 Isotopes of the same element have the same properties because they have the same atomic number (the same number protons) • • Go to Section: 12 C 6 13 C 6 14 C 6 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. Go to Section: 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. Go to Section: 12 Atoms in compounds are held together by chemical bonds—either ionic or covalent. Go to Section: Figure 2-3 Ionic Bonding Section 2-1 13 Ionic bonds: attraction of negative ions to positive ions because a metal donates its electrons to a nonmetal atom, forming stable Chloride ion (Cl-) ions with complete valence shell octets. Sodium ion (Na+) Sodium atom (Na) Chlorine atom (Cl) Transfer of electron Protons +11 Electrons -11 Charge 0 Go to Section: Protons +17 Electrons -17 Charge 0 Protons +11 Electrons -10 Charge +1 Protons +17 Electrons -18 Charge -1 13 Covalent bonds form when nonmetal atoms share electrons to fill their valence octets, linking atoms because both nuclei attract the shared electrons Go to Section: . Figure 2-3 Ionic Bonding Section 2-1 14 Sodium atom (Na) Ions are atoms carrying a charge after losing or gaining valence electrons.+ Chlorine atom (Cl) Sodium ion (Na ) Chloride ion (Cl-) Transfer of electron Protons +11 Electrons -11 Charge 0 Go to Section: Protons +17 Electrons -17 Charge 0 Protons +11 Electrons -10 Charge +1 Protons +17 Electrons -18 Charge -1 15. False. Atom that loses electrons becomes a positive ion. Go to Section: 16 Molecules (Not ionic compounds!) form when atoms are joined with covalent bonds. Go to Section: 17 A is false—2 shared electrons is a single covalent bond b A •D covalent bonds are formed when atoms share electrons C http://academic.brooklyn.cuny.edu/biology/bio4fv/page/covalent_bonds.html Go to Section: 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/Haine sIMF/images/dipoledipole.jpg Go to Section: Lesson 3: Chapter 2 The chemistry of Life 1. 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. 2. Complete water lab, then turn in one copy per lab group . Teacher will select one student’s report. 3. 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. Go to Section: Section Outline Section 2-2 Go to Section: • • 2–2 Properties of Water, • the strangest and most important molecule on earth! http://www.wsi.nrcs.usda.gov/products/i mages/wq_drop.jpg http://www.sumanasinc.com/webcontent/ani mations/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. Go to Section: Guided reading & study workbook for section 2.2, p 15--16 1. Water molecules contain 10 electrons, 1 for each H and eight for O. Water molecules also contain 10 protons True or False. Water molecules are neutral. 1.True 2.False Go to Section: 2. Because water molecules have O at one end and H at the other, the entire molecule: 1.Is positively charged 2.Is negatively charged 3.Is polar, with partial + & - charges. Go to Section: 3. Water is a polar covalent molecule because: 1.More electronegative O atoms are bonded to less electronegative H atoms 2.O carries a δ- charge & H’s a δ+ charge 3.The shared electrons of each O—H covalent bond are more strongly attracted to the O 4.All of the above 5.None of the above Go to Section: • • • • • • Strongest 2nd strongest 3rd strongest 4th strongest 5th strongest 6th strongest • 7th strongest • Go to Section: triple covalent bond double covalent bond single covalent bond ionic bond Hydrogen bonds Dipole dipole interactions (polar molecules attracted δ+ to δ- ) OTHER than Hydrogen bonds Van der Waals forces (hydrophobic interactions of nonpolar compounds) 4. Which statement is True? 1.Hydrogen bonds are stronger than ionic bonds. 2.Attraction of the H in one water molecule to O in another is a Hydrogen bond 3.Hydrogen bonds are stronger than covalent bonds 4.Hydrogen bonds are the strongest bonds BETWEEN different neutral molecules. 5.Choices 2 and 5 are true Go to Section: cohesion Go to Section: 5. Cohesion is: 1.Attraction of δ+ and δ- atoms of water molecules to atoms or ions of other substances, like the glass in a graduated cylinder 2.Attraction of δ+ H and δ- O of water molecules atoms in adjacent water molecules Go to Section: 5. Adhesion (exhibited by water adhering to the spider web) is: 1.Attraction of δ+ and δ- atoms of water molecules to atoms or ions of other substances, like the glass in a graduated cylinder 2.Attraction of δ+ H and δ- O of water molecules atoms in adjacent water molecules Go to Section: 6. Water is cohesive (shown by water’s forming droplets) because: 1.δ+ H and δ- O atoms of water molecules are attracted to each other in the same molecule 2.δ+ H and δ- O atoms of water molecules are attracted to each other in adjacent molecules Go to Section: Surface tension versus capillary action Go to Section: 7. The rise of water in a narrow tube (like water rising in a thermometer) against the force of gravity is: 1.surface tension 2. capillary action 3. specific heat Go to Section: 8 In plants capillary action: 1. Draws water upwards from the roots into the leaves through thin tubes called xylem 2. Pulls sugar downwards from the leaves into the roots through thin tubes called phloem Go to Section: 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 Go to Section: 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 Go to Section: 9. True or False. Sucrose (C6H12O6) is a mixture. se 50% Fa l Go to Section: Tr ue 1. True 2. False 50% 9. True or False. Sucrose (C6H12O6) dissolved in water is a mixture. se 50% Fa l Go to Section: Tr ue 1. True 2. False 50% 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. Go to Section: 10. This picture shows bananas mashed up in water. This mixture is a 50% 50% Go to Section: ut io n so l su sp e ns io n 1.suspension 2.solution 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) Go to Section: 12. A suspension is a: 1. Homogeneous mixture 2. Heterogeneous mixture 3. Unstable (particles settle out over time) 4. Stable (a solution whose solutes do not settle out) 5. 2 and 3 bl e St a 3 nd 2a (a so lu ... t. . . (p ar e Un st ab l og en eo us .. . i. . . us m He te r en eo og Ho m Go to Section: 20% 20% 20% 20% 20% Parts of Solutions: Solvent: more abundant—does the dissolving Solute: less abundant—gets dissolved Go to Section: 13. Two liters water are mixed with 0.3 liters salt. The water is the 1. solution 2. solute 3. solvent Go to Section: ve n t 33% so l ut e 33% so l so l ut io n 33% 14. Two liters water are mixed with 0.3 liters salt. The salt is the 1. solution 2. solute 3. solvent Go to Section: ve n t 33% so l ut e 33% so l so l ut io n 33% 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 Go to Section: 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 Go to Section: 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) Go to Section: 14. Two water molecules can react to form: 2H2O(l) → H3O+(aq) + OH–(aq) 50% 50% hy ... & um on i Hy dr Go to Section: No np o lar co m po .. . 1. Nonpolar compounds 2. Hydronium & hydroxide ions 15. Water is neutral because it: 1. Is polar covalent 2. Forms Hydrogen bonds 3. Has equal numbers of hydronium & hydroxide ions 4. Is nonpolar covalent ar po l Is no n ln eq ua co . .. um b. .. ... ge n Ha s co ar Is po l Go to Section: Fo rm sH yd ro va l ... 25% 25% 25% 25% Acids increase the H1+ content of water in aqueous solutions. Bases increase the OH1HCl H+ + ClNaOH Na1+ + OH1- Go to Section: pH Scale Section 2-2 Go to Section: Neutral Increasingly Acidic pH measures whether either H+ ions are greater (acidic) or the OH1ions are greater (basic) Increasingly Basic Oven cleaner Bleach Ammonia solution Soap Sea water Human blood Pure water Milk Normal rainfall Acid rain Tomato juice Lemon juice Stomach acid The more H+ ions, the more acidic, the lower pH. The more OH1ions, the more basic, the higher pH. 16. The pH scale indicates: 1. The acidity of an aqueous solution 2. The basicity of an aqueous solution 3. The concentration of H+ ions present relative to concentration of the OH- ions 4. All of these. Th e e. he s of t Al l ici ba s Th e co nc en ty tra t.. . o. .. of . .. ity ac id Th e Go to Section: 25% 25% 25% 25% 17. Which of these aqueous solutions is most 20% 20% 20% 20% 20% acidic? pH 3 pH 5 pH 7 Go to Section: pH 11 pH9 pH11 pH7 pH5 pH3 pH 9 1. 2. 3. 4. 5. pH Scale Section 2-2 So, pH 0 has 10 times more H+ than pH1 and 100 times more than pH2. Go to Section: Neutral Increasingly Acidic The pH scale is logarithmic. Increasingly Basic Oven cleaner Bleach Ammonia solution Soap Sea water Human blood Pure water Milk Normal rainfall Acid rain Tomato juice Lemon juice Stomach acid pH 7 has 10 times less H+ than pH6 and 100 times less than pH5 18. How many more H+ ions does a solution with pH 4 have than one with pH 5? 25% ss ... It h as 1X le m or e 10 X m or or m Go to Section: 25% e 25% e 25% 10 0X 1X more 10X more 100X more It has 1X less than pH5 1X 1. 2. 3. 4. 19. Which statement is false? 1. Acidic solution pH is < 7 2. Acids add H+ to solutions 3. Strong acids make solutions whose pH is 11--14 4. Acidic solutions have higher concentrations of H+ than pure water ha ve hi .. . t.. . so lu Ac id ic so l sm ac id ng St ro ut io ns ak e so l to H+ sa dd Ac id ic so l Ac id Go to Section: ut io n pH is ut io ns <7 25% 25% 25% 25% Go to Section: pH Go to Section: Interest Grabber Section 2-3 Life’s Backbone •Most of the compounds that make up living things contain carbon. In fact, carbon makes up the basic structure, or “backbone,” of these compounds. Each atom of carbon has four electrons in its outer energy level, which makes it possible for each carbon atom to form four bonds with other atoms. •As a result, carbon atoms can form long chains. A huge number of different carbon compounds exist. Each compound has a different structure. For example, carbon chains can be straight or branching. Also, other kinds of atoms can be attached to the carbon chain. Go to Section: Interest Grabber continued Section 2-3 • 1. On a sheet of paper, make a list of at least ten things that contain carbon. • 2. Working with a partner, review your list. If you think some things on your list contain only carbon, write “only carbon” next to them. • 3. If you know other elements that are in any items on your list, write those elements next to them. Go to Section: Section Outline Section 2-3 • 2–3 Carbon Compounds A. B. C. D. E. F. Go to Section: The Chemistry of Carbon Macromolecules Carbohydrates Lipids Nucleic Acids Proteins Concept Map Section 2-3 Carbon Compounds include Carbohydrates Lipids Nucleic acids Proteins that consist of that consist of that consist of that consist of Sugars and starches Fats and oils Nucleotides Amino Acids which contain which contain Carbon, hydrogen, oxygen Go to Section: Carbon, hydrogen, oxygen which contain which contain Carbon,hydrogen, oxygen, nitrogen, phosphorus Carbon, hydrogen,oxygen, nitrogen, Figure 2-11 Carbon Compounds Section 2-3 Methane Go to Section: Acetylene Butadiene Benzene Isooctane Figure 2-13 A Starch Section 2-3 Starch Glucose Go to Section: Figure 2-16 Amino Acids Section 2-3 Amino group Carboxyl group General structure Go to Section: Alanine Serine Figure 2-16 Amino Acids Section 2-3 Amino group Carboxyl group General structure Go to Section: Alanine Serine Figure 2-16 Amino Acids Section 2-3 Amino group Carboxyl group General structure Go to Section: Alanine Serine Figure 2-17 A Protein Section 2-3 Amino acids Go to Section: Interest Grabber Section 2-4 Matter and Energy •Have you ever sat around a campfire or watched flames flicker in a fireplace? The burning of wood is a chemical reaction—a process that changes one set of chemicals into another set of chemicals. A chemical reaction always involves changes in chemical bonds that join atoms in compounds. The elements or compounds that enter into a chemical reaction are called reactants. The elements or compounds produced by a chemical reaction are called products. As wood burns, molecules of cellulose are broken down and combine with oxygen to form carbon dioxide and water vapor, and energy is released. Go to Section: Interest Grabber continued Section 2-4 • 1. What are the reactants when wood burns? • 2. What are the products when wood burns? • 3. What kinds of energy are given off when wood burns? • 4. Wood doesn’t burn all by itself. What must you do to start a fire? What does this mean in terms of energy? • 5. Once the fire gets started, it keeps burning. Why don’t you need to keep restarting the fire? Go to Section: Section Outline Section 2-4 • 2–4 Chemical Reactions and Enzymes A. Chemical Reactions B. Energy in Reactions 1. Energy Changes 2. Activation Energy C. Enzymes D. Enzyme Action 1. The Enzyme-Substrate Complex 2. Regulation of Enzyme Activity Go to Section: Effect of Enzymes Section 2-4 Reaction pathway without enzyme Activation energy without enzyme Reactants Reaction pathway with enzyme Activation energy with enzyme Products Go to Section: Figure 2-19 Chemical Reactions Section 2-4 Energy-Absorbing Reaction Energy-Releasing Reaction Activation energy Products Activation energy Reactants Reactants Products Go to Section: Figure 2-19 Chemical Reactions Section 2-4 Energy-Absorbing Reaction Energy-Releasing Reaction Activation energy Products Activation energy Reactants Reactants Products Go to Section: Figure 2-21 Enzyme Action Section 2-4 Enzyme (hexokinase) Glucose Substrates Products ADP Glucose-6phosphate Products are released ATP Active site Enzyme-substrate complex Substrates are converted into products Go to Section: Substrates bind to enzyme Figure 2-21 Enzyme Action Section 2-4 Enzyme (hexokinase) Glucose Substrates Products ADP Glucose-6phosphate Products are released ATP Active site Enzyme-substrate complex Substrates are converted into products Go to Section: Substrates bind to enzyme Figure 2-21 Enzyme Action Section 2-4 Enzyme (hexokinase) Glucose Substrates Products ADP Glucose-6phosphate Products are released ATP Active site Enzyme-substrate complex Substrates are converted into products Go to Section: Substrates bind to enzyme Figure 2-21 Enzyme Action Section 2-4 Enzyme (hexokinase) Glucose Substrates Products ADP Glucose-6phosphate Products are released ATP Active site Enzyme-substrate complex Substrates are converted into products Go to Section: Substrates bind to enzyme Videos • Click a hyperlink to choose a video. • Atomic Structure • Energy Levels and Ionic Bonding • Covalent Bonding • Enzymatic Reactions Video 1 Atomic Structure •Click the image to play the video segment. Video 2 Energy Levels and Ionic Bonding Click the image to play the video segment. Video 3 Covalent Bonding Click the image to play the video segment. Video 4 Enzymatic Reactions Click the image to play the video segment. Go Online •Career links on forensic scientists •Interactive test •Articles on organic chemistry •For links on properties of water, go to www.SciLinks.org and enter the Web Code as follows: cbn-1022. •For links on enzymes, go to www.SciLinks.org and enter the Web Code as follows: cbn-1024. Interest Grabber Answers • • • • • • • • • • 1. Give an example of solid matter. Sample answers: books, desks, chairs 2. Give an example of liquid matter. Sample answers: water, milk 3. Give an example of gaseous matter. Sample answers: air, helium in a balloon 4. Is all matter visible? No 5. Does all matter take up space? Yes Interest Grabber Answers • 1. Working with a partner, make a list of ten things that have water in them. • Possible answers: bodies of water, rain and snow, soft drinks and other beverages, juicy foods such as fruits, and so on. • 2. Exchange your list for the list of another pair of students. Did your lists contain some of the same things? Did anything on the other list surprise you? • Students’ answers will likely be similar, but not exactly alike. • 3. Did either list contain any living things? • Students’ lists may include plants, animals, or other living things. Interest Grabber Answers • • • • • • 1. On a sheet of paper, make a list of at least ten things that contain carbon. Students will likely know that charcoal and coal contain carbon. They may also list carbohydrates (starches and sugars), oil, gasoline, wood, or carbon dioxide. 2. Working with a partner, review your list. If you think some things on your list contain only carbon, write “only carbon” next to them. Students will say that charcoal and coal contain only carbon. While these materials do contain small amounts of other elements, such as sulfur, they are composed mostly of carbon. 3. If you know other elements that are in any items on your list, write those elements next to them. Students may know that many carbon compounds also contain oxygen and/or hydrogen. Interest Grabber Answers 1. What are the reactants when wood burns? Reactants are oxygen and cellulose. 2. What are the products when wood burns? Products are carbon dioxide and water. 3. What kinds of energy are given off when wood burns? Light and heat are given off. Some students may also mention sound (the crackling of a fire). 4. Wood doesn’t burn all by itself. What must you do to start a fire? What does this mean in terms of energy? To start a fire, you must light it with a match and kindling. You are giving the wood some energy in the form of heat. 5. Once the fire gets started, it keeps burning. Why don’t you need to keep restarting the fire? Once the fire gets going, it gives off enough heat to start more of the wood burning. •This slide is intentionally blank.