1. Chapter 1: Chemistry and the Atomic/Molecular View of Matter Chemistry: The Molecular Nature of Matter, 6E Jespersen/Brady/Hyslop

2. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 1.1 Chemistry and the Sciences Chemistry:  Study of matter. (composition, properties, and transformation of matter) Chemist:  Seeks answers to fundamental questions about:  What makes up materials that compose our world  How composition affects properties of substances  How substances change when they interact with each other = Chemical Reactions 2

3. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Chemistry and the Sciences Chemistry  Touches all of the natural sciences.  Central of science. Although if you not plan to be a chemist, some knowledge of chemistry will surely be valuable to you.  knowledge to:  Create new materials not found in nature  Understand fundamental biological processes that taking place in living organisms. 3

4. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Names of Some of the Divisions of the American Chemical Society 4 Agricultural & Food Chemistry Chemical Health and Safety Biochemical TechnologyComputer in chemistry Biological ChemistryEnvironmental chemistry Cellulose Paper and TextilePetroleum Chemistry Industrial and Engineering Chemistry Medicinal chemistry Nuclear Chemistry and Technology Business Development & Management

5. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 1.2 Scientific Method  Approach to gathering information & formulating explanations.  Scientists perform experiments in laboratories under controlled conditions 1.Make observations/collect data  Qualitative  Descriptions  Quantitative  Measurements 5

6. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Scientific Method 2.Law or Scientific Law  Based on results of many experiments  Only states what happens  Doesn’t explain why they happen 3.Formulate Hypothesis  Possible Explanations for Observed Characteristics or Behaviors  Perform Experiments  Test Hypothesis 6

7. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Scientific Method 4.Theory  Tested explanation of how nature behaves  Devise further tests  Depending on results, may have to modify theory  Can never prove theory is absolutely correct 7

8. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Scientific Method Ex. Study gases  Discover Volume (V) of gas depends on  Pressure (P)  Temperature (T)  Amount (n)  Data  Recorded observations of relationship between V, P, T & n  Law  R = constant  Kinetic Theory of Gases  Explains gas behavior (Ch 11) 8

9. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Atomic Theory  Most significant theoretical model of nature Atoms  Tiny submicroscopic particles  Make up all chemical substances  Make up everything in Macroscopic world  Smallest particle that has all properties of given element  Composed of:  Electrons  Neutrons  Protons 9

10. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 1.3 Matter & Its Classifications Matter  Anything that has mass & occupies space 10

11. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Pure Substance vs. Mixture Pure substances  Made up of one type of substance.  Elements and compounds  Composition always same regardless of source Mixture  Made up of two or more substances  Can have variable compositions Ex. CO 2 in water—varying amounts of “fizz” in soda  2 broad categories of mixtures:  Heterogeneous  Homogeneous 11

12. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Elements  Substances that can’t be decomposed into simpler materials by chemical reactions  Substances composed of only 1 type of atom  Simplest forms of matter that we can work with directly  More complex substances composed of elements in various combinations 12 diamond = carbongold sulfur

13. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Chemical Symbols for Elements Chemical Symbol  One or two letter symbol for each element name  First letter capitalized, second letter lower case Ex. C = carbonS = sulfur Ca = calciumAr = argon Br = bromineH = hydrogen Cl = chlorineO = oxygen  Most based on English name  Some based on Latin or German names 13

14. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Chemical Symbols English NameChemical SymbolLatin Name SodiumNaNatrium Potassium KKalium IronFeFerrum CopperCuCuprum SilverAgArgentum GoldAuAurum MercuryHgHydrargyrum AntimonySbStibium TinSnStannium LeadPbPlumbum TungstenWWolfram (German) 14

15. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Compounds  Formed from 2 or more atoms of different elements  Always combined in same fixed ratios by mass  Can be broken down into elements by some chemical changes Ex. Water decomposed to elemental hydrogen & oxygen Mass of oxygen = 8 × mass of hydrogen 15

16. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Homogeneous Mixtures  Same properties throughout sample  Solution  Thoroughly stirred homogeneous mixture Ex.  Liquid solution  Sugar in water  Gas solution  Air  Contains nitrogen, oxygen, carbon dioxide & other gases  Solid solution  US 5¢ coin – Metal Alloy  Contains copper & nickel metals 16

17. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Heterogeneous Mixtures  2 or more regions of different properties  Solution with multiple phases  Separate layers Ex.  Salad dressing  Oil & vinegar  Ice & water  Same composition  2 different physical states 17

18. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Learning Check: Classification Hot Cocoa Ice (H 2 O) White Flour Table Salt (NaCl) Pure substance Element Compound Molecule Heterogeneous Mixture Homogeneous Mixture 18 X X X XX X X

19. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Physical Change  No new substances formed  Substance may change state or the proportions Ex. Ice melting  Sugar or salt dissolving  Stirring iron filings & sulfur together 19

20. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Chemical Change or Chemical Reaction  Formation of new substance or compound  Involves changing chemical makeup of substances  New substance has different physical properties  Can’t be separated by physical means Ex.  Fool’s gold  Compound containing sulfur & iron  No longer has same physical properties of free elements  Can’t be separated using magnet 20

21. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Learning Check: ChemicalPhysical Magnesium burns when heated Magnesium metal tarnishes in air Magnesium metal melts at 922 K Grape Kool-aid lightens when water is added 21  For each of the following, determine if it represents a Chemical or Physical Change: X X X X

22. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 1.4 Dalton’s Atomic Theory John Dalton  Developed underlying theory to explain  Law of Conservation of Mass  Law of Definite Proportions  Reasoned that if atoms exist, they have certain properties 22

23. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Dalton’s Atomic Theory 1. Matter consists of tiny particles called atoms. 2.Atoms are indestructible.  In chemical reactions, atoms rearrange but do not break apart. 3.In any sample of a pure element, all atoms are identical in mass & other properties. 4.Atoms of different elements differ in mass & other properties. 5.In given compound, constituent atoms are always present in same fixed numerical ratio. 23

24. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Proof Of Atoms  Early 1980’s, use Scanning Tunneling Microscope (STM)  Surface can be scanned for topographical information  Image for all matter shows spherical regions of matter  Atoms 24 STM of palladium

25. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Molecules  Atoms combine to form more complex substances  Discrete particles  Each composed of 2 or more atoms Ex.  Molecular oxygen, O 2  Carbon dioxide, CO 2  Ammonia, NH 3  Sucrose, C 12 H 22 O 11 25

26. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Chemical Formulas  Specify composition of substance  Chemical symbols  Represent atoms of elements present  Subscripts  Given after chemical symbol  Represents relative numbers of each type of atom Ex. Fe 2 O 3 : iron & oxygen in 2:3 ratio 26

27. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Chemical Formulas Free Elements  Element not combined with another in compounds  Just use chemical symbol to represent Ex. Iron FeNeonNe SodiumNaAluminumAl Diatomic Molecule  Molecules composed of 2 atoms each  Many elements found in nature Ex. OxygenO 2 NitrogenN 2 HydrogenH 2 ChlorineCl 2 27

28. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Depicting Molecules  Want to show:  Order in which atoms are attached to each other  3-dimensional shape of molecule  Three ways of visualizing molecules: 1. Structural formula 2. Ball-and-Stick model 3. Space filling model 28

29. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Structural Formulas  Use to show how atoms are attached  Atoms represented by chemical symbols  Chemical bonds attaching atoms indicated by lines 29 H 2 O water CH 4 methane

30. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Hydrates  Crystals that contain water molecules Ex. plaster: CaSO 4 ∙2H 2 O calcium sulfate dihydrate  Water is not tightly held  Dehydration  Removal of water by heating  Remaining solid is anhydrous (without water) 30 Blue = CuSO 4 5H 2 O White = CuSO 4

31. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Counting Atoms 1.Subscript following chemical symbol indicates how many of that element are part of the formula  No subscript implies a subscript of 1. 2.Quantity in parentheses is repeated a number of times equal to the subscript that follows. 3.Raised dot in formula indicates that the substance is a hydrate  Number preceding H 2 O specifies how many water molecules are present. 31

32. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Counting Atoms Ex. 1 (CH 3 ) 3 COH  Subscript 3 means 3 CH 3 groups So from(CH 3 ) 3, we get 3 × 1C = 3C 3 × 3H = 9H #C = 3C + 1C = 4 C #H = 9H + 1H = 10 H #O = 1 O Total # of atoms = 15 atoms 32

33. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Counting Atoms Ex. 2 CoCl 2 · 6H 2 O  The dot 6H 2 O means you multiple both H 2 & O by 6  So there are: #H6 × 2 = 12 H #O6 × 1 = 6 O #Co1 × 1 = 1 Co #Cl2 × 1 = 2 Cl Total # of atoms = 21 atoms 33

34. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Your Turn! a.Na 2 CO 3 b.(NH 4 ) 2 SO 4 c.Mg 3 (PO 4 ) 2 d.CuSO 4 ∙5H 2 O e.(C 2 H 5 ) 2 N 2 H 2 34 a.___Na, ___ C, ___ O b.___N, ___H, ___S, ___O c.___Mg, ___P, ___O d.___Cu, ___S, ___O, ___H e.___C, ___H, ___N 321 2814 328 1 1 910 Count the number of each type of atom in the chemical formula given below 4 12 2

35. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Dalton’s Atomic Theory Successes:  Explains Law of Conservation of Mass  Chemical reactions correspond to rearranging atoms.  Explains Law of Definite Proportions  Given compound always has atoms of same elements in same ratios.  Predicted Law of Multiple Proportions  Not yet discovered  Some elements combine to give 2 or more compounds Ex. SO 2 & SO 3 35

36. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Law Of Multiple Proportions  When 2 elements form more than one compound, different masses of one element that combine with same mass of other element are always in ratio of small whole numbers.  Atoms react as complete (whole) particles.  Chemical formulas  Indicate whole numbers of atoms  Not fractions 36

37. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Using Law Of Multiple Proportions sulfursulfur dioxidetrioxide Mass S 32.06 g32.06 g Mass O 32.00 g48.00 g  Use this data to prove law of multiple proportions 37

38. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 1.6 Chemical Reactions  When 1 or more substances react to form 1 or more new substances Ex. Reaction of methane, CH 4, with oxygen, O 2, to form carbon dioxide, CO 2, & water, H 2 O. Reactants = CH 4 & O 2 Products = CO 2 & H 2 O  How to depict?  Words too long  Pictures too awkward 38

39. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Chemical Equations  Use chemical symbols & formulas to represent reactants & products.  Reactants on left hand side  Products on right hand side  Arrow (  ) means “reacts to yield” Ex. CH 4 + 2O 2  CO 2 + 2H 2 O  Coefficients  Numbers in front of formulas  Indicate how many of each type of molecule reacted or formed  Equation reads “methane & oxygen react to yield carbon dioxide & water” 39

40. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Conservation of Mass in Reactions  Mass can neither be created nor destroyed  This means that there are the same number of each type of atom in reactants & in products of reaction  If # of atoms same, then mass also same 40 CH 4 + 2O 2  CO 2 + 2H 2 O 4 H + 4O + C = 4 H + 4O + C

41. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Balanced Chemical Equation Ex. 2C 4 H 10 + 13O 2  8CO 2 + 10H 2 O 41 4 C & 10 H per molecule 2 O per molecule 2 H & 1 O per molecule 1 C & 2 O per molecule Subscripts  Define identity of substances  Must not change when equation is balanced

42. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Balanced Chemical Equation Ex. 2C 4 H 10 + 13O 2  8CO 2 + 10H 2 O 42 2 molecules of C 4 H 10 13 molecules of O 2 10 molecules of C 4 H 10 8 molecules of CO 2 Coefficients  Number in front of formulas  Indicate number of molecules of each type  Adjusted so # of each type of atom is same on both sides of arrow  Can change

43. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Balanced Chemical Equations  How do you determine if an equation is balanced?  Count atoms  Same number of each type on both sides of equation?  If yes, then balanced  If no, then unbalanced Ex. 2C 4 H 10 + 13O 2  8CO 2 + 10H 2 O ReactantsProducts 2×4 = 8 C8×1 = 8 C 2×10 = 20 H10×2 = 20 H 13×2 = 26 O (8×2)+(10×1)= 26 O 43

44. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Learning Check Fe(OH) 3 + 2 HNO 3  Fe(NO 3 ) 3 + 2 H 2 O  Not Balanced  Only Fe has same number of atoms on either side of arrow. 44 ReactantsProducts Fe11 3 + (2×3) = 9 (3×3) + 2 = 11 O 3 + 2 = 5(2×2) = 4 H 23 N

45. Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Your Turn! How many atoms of each element appear on each side of the arrow in the following equation? 4NH 3 + 3O 2 → 2N 2 + 6H 2 O 45 ReactantsProducts N(4 × 1) = 4(2 × 2) = 4 O(3 × 2) = 6(6 × 1) = 6 H(4 × 3) = 12(6 × 2) = 12