2. www.unit5.org/chemistry States of Matter, Properties of Matter, & Changes in Matter Unit 2

3. States of Matter Kinetic Molecular Theory -

4. A. Kinetic Theory of Matter: explains how particles in matter behave. 1. All matter is composed of small particles (molecules ) 2. Molecules are in constant random motion 3. Thermal Energy: total energy of a material’s particles – both kinetic & potential 4. Average Kinetic Energy ( KE ): temperature of the substance –a. The lower the temperature, the slower the particles motion –b. The state/ phase of matter depends on its KE

6. Temperature is Average Kinetic Energy Fast Slow “HOT” “COLD” Kinetic Energy (KE) = ½ m v 2 *Vector = gives direction and magnitude

7. Thermal Expansion Most objects e-x-p-a-n-d when heated Large structures such as bridges must be built to leave room for thermal expansion All features expand together COLD HOT Cracks in sidewalk.

8. Solid, Liquid, Gas (a) Particles in solid (b) Particles in liquid (c) Particles in gas

9. Solid H 2 O (s) Ice Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 31 molecules are in constant motion – slight vibrations Solids have a definite shape Solids have a definite volume

10. Ice H 2 O (s) Ice Photograph of ice model Photograph of snowflakes Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

11. Liquid H 2 O (l) Water Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 31 In a liquid molecules are in constant motion there are appreciable intermolecular forces molecules are close together Liquids are almost incompressible Liquids do not fill the container

12. Liquids The two key properties we need to describe are EVAPORATIONCONDENSATION EVAPORATION and its opposite CONDENSATION add energy and break intermolecular bonds EVAPORATION release energy and form intermolecular bonds CONDENSATION

13. Gas H 2 O (g) Steam Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 31

14. D. Gaseous State : No Definite Shape & No Definite Volume  1. Have enough energy to escape the attractive forces of the other particles in the liquid state  2. Particles have high KE  3. Particles spread evenly throughout their container in a process called diffusion  4. At boiling point, the pressure of the liquid’s vapor is equal to that of the atmosphere and the liquid becomes a gas

15. States of Matter

16. Gas, Liquid, and Solid Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 441 Gas Liquid Solid

17. States of Matter Solid Liquid Gas Holds Shape Fixed Volume Shape of Container Free Surface Fixed Volume Shape of Container Volume of Container heat

18. Some Properties of Solids, Liquids, and Gases Property Solid Liquid Gas Shape Has definite shapeTakes the shape of Takes the shape the container of its container Volume Has a definite volumeHas a definite volume Fills the volume of the container Arrangement of Fixed, very closeRandom, close Random, far apart Particles Interactions between Very strongStrong Essentially none particles

19. To evaporate, molecules must have sufficient energy to break IM forces. Molecules at the surface break away and become gas. Only those with enough KE escape. endothermicBreaking IM forces requires energy. The process of evaporation is endothermic. Evaporation is a cooling process. It requires heat. Evaporation

20. Change from gas to liquid Achieves a dynamic equilibrium with vaporization in a closed system. What is a closed system? A closed system means matter can’t go in or out. (put a cork in it) What the heck is a “dynamic equilibrium?” Condensation

21. Vaporization is an endothermic process - it requires heat. Energy is required to overcome intermolecular forces Responsible for cool earth Why we sweat Vaporization

22. Energy Changes Accompanying Phase Changes Solid Liquid Gas Melting Freezing Deposition CondensationVaporization Sublimation Energy of system Brown, LeMay, Bursten, Chemistry  2000, page 405

23. solid liquid gas Heat added Temperature ( o C) A B C D E Heating Curve for Water 0 100 LeMay Jr, Beall, Robblee, Brower, Chemistry Connections to Our Changing World, 1996, page 487

24. solid liquid gas vaporization condensation melting freezing Heat added Temperature ( o C) A B C D E Heating Curve for Water 0 100 LeMay Jr, Beall, Robblee, Brower, Chemistry Connections to Our Changing World, 1996, page 487

25. Properties of Matter

26. http://antoine.frostburg.edu/chem/senese/101/matter/slides/sld001.htm Pyrex Pyrex Extensive Properties Intensive Properties volume: mass: density: temperature: 100 mL 99.9347 g 0.999 g/mL 20 o C 15 mL 14.9902 g 0.999 g/mL 20 o C

27. Physical Property: Observed without changing the chemical composition of the matter Ex: color, texture, etc.

28. Properties of Matter Electrical Conductivity Heat Conductivity Density Melting Point Boiling Point Malleability Ductility

30. Physical Properties Examples of Physical Properties Boiling point Color SlipperinessElectrical conductivity Melting point TasteOdorDissolves in water Shininess (luster) SoftnessDuctilityViscosity (resistance to flow) Volatility HardnessMalleabilityDensity (mass / volume ratio) Ralph A. Burns, Fundamentals of Chemistry 1999, page 23

31. Chemical Properties Characteristic of a substance that indicates whether it can undergo a certain chemical change – Will rust, flammable, oxidizes, ferments, tarnishes

32. Chemical Property: The tendency of a substance to change into another substance. caused by iron (Fe) reacting with oxygen (O 2 ) to produce rust (Fe 2 O 3 ) Steel rusting: 4 Fe + 3 O 2 2 Fe 2 O 3

33. Chemical Properties Examples of Chemical Properties Burns in air Reacts with certain acidsDecomposes when heated Explodes Reacts with certain metalsReacts with certain nonmetals Tarnishes Reacts with waterIs toxic Ralph A. Burns, Fundamentals of Chemistry 1999, page 23 Chemical properties can ONLY be observed during a chemical reaction !

34. Physical Change IDENTITY DOES NOT CHANGE!! – a change in size, shape, or state of matter – All phase changes are physical changes!! – may or may not involve energy changes and color changes

35. During a “physical change” a substance changes some physical property… During a “physical change” a substance changes some physical property… H2OH2O

36. …but it is still the same material with the same chemical composition. H2OH2O gas solid liquid

37. Chemical Change: Any change involving a rearrangement of atoms.

38. Chemical Reaction: The process of a chemical change...

39. During a “chemical reaction” new materials are formed by a change in the way atoms are bonded together. During a “chemical reaction” new materials are formed by a change in the way atoms are bonded together.

40. Chemical Change change in identity- changes the COMPOUND or SUBSTANCE – Dark bottles- block light- prevents change in identity

41. Indications that a chemical change MAY have occurred: Change in Smell, Heat, Light, Sound, Color change, production of gas or precipitate Color change does not always indicate a chemical change – Example: blue and yellow make green- physical change- just a mixture, – kool-aid added to water

42. Chemical Changes http://www.ric.edu/faculty/ptiskus/chemical/ Chemical changes can be used to separate substances- done in labs- metals can be removed from ore this way

43. Weathering – Physical change when rocks split as water freezes or as erosion occurs – Chemical change when acidic water reacts with limestone and results in a new substance that dissolves in water and washes away.

44. Physical & Chemical Changes Limestone, CaCO 3 crushing PHYSICAL CHANGE Crushed limestone, CaCO 3 heating CHEMICAL CHANGEPyrex CO 2 CaO Lime and carbon dioxide, CaO + CO 2

45. The formation of a mixture The formation of a compound Chemical Change Physical Change

46. Law of Conservation of Mass Mass cannot be created or destroyed – Burning a log seems to make mass disappear – “missing” mass is actually present in the gases that are produced as the log burns – http://www.quia.com/quiz/303980.html http://www.quia.com/quiz/303980.html

47. Conservation of Matter Reactants yield Products

48. ELEMENT hydrogen molecule, H 2 ELEMENT oxygen molecule, O 2 MIXTURE a mixture of hydrogen and oxygen molecules CHEMICAL REACTION if molecules collide with enough force to break them into atoms, a can take place COMPOUND water, H 2 O

49. 2 H 2 O2O2 O2O2 2 H 2 O + + + + E E Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

50. The Zeppelin LZ 129 Hindenburg catching fire on May 6, 1937 at Lakehurst Naval Air Station in New Jersey.

51. S.S. Hindenburg 35 people died when the Hindenburg exploded. May 1937 at Lakehurst, New Jersey German zeppelin luxury liner Exploded on maiden voyage Filled with hydrogen gas

52. Hydrogen is the most effective buoyant gas, but is it highly flammable. The disastrous fire in the Hindenburg, a hydrogen-filled dirigible, in 1937 led to the replacement of hydrogen by nonflammable helium.

53. As time goes by the rate of vaporization remains constant but the rate of condensation increases because there are more molecules to condense. Equilibrium is reached when: Rate of Vaporization = Rate of Condensation Molecules are constantly changing phase “dynamic” The total amount of liquid and vapor remains constant “equilibrium” Dynamic Equilibrium

54. Copyright © 2007 Pearson Benjamin Cummings. All rights reserved. (a) Radiant energy(b) Thermal energy (c) Chemical energy(d) Nuclear energy(e) Electrical energy

55. The energy something possesses due to its motion, depending on mass and velocity. Potential energy Energy in Energy out kinetic energy

56. Energy Kinetic Energy – energy of motion KE = ½ m v 2 Potential Energy – stored energy Batteries (chemical potential energy) Spring in a watch (mechanical potential energy) Water trapped above a dam (gravitational potential energy) massvelocity (speed) B A C

57. Hot vs. Cold Tea Kinetic energy Many molecules have an intermediate kinetic energy Few molecules have a very high kinetic energy Low temperature (iced tea) High temperature (hot tea) Percent of molecules

58. Exothermic vs. Endothermic

60. Decomposition of Nitrogen Triiodide

61. 2 NI 3 (s) N 2 (g) + 3 I 2 (g) NI 3 I2I2 N2N2

62. Exothermic Reaction Reactants  Products + Energy 10 energy = 8 energy + 2 energy Reactants Products -H-H Energy Energy of reactants Energy of products Reaction Progress

63. Endothermic Reaction Energy + Reactants  Products +  H Endothermic Reaction progress Energy Reactants Products Activation Energy

64. Effect of Catalyst on Reaction Rate reactants products Energy activation energy for catalyzed reaction Reaction Progress No catalyst Catalyst lowers the activation energy for the reaction. What is a catalyst? What does it do during a chemical reaction?

65. An Energy Diagram activated complex activation energy EaEa reactants products course of reaction energy Animation by Raymond Chang All rights reserved

66. Burning of a Match Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 293 Energy released to the surrounding as heat SurroundingsSystem (Reactants)  (PE) Potential energy (Products)

67. Conservation of Energy in a Chemical Reaction Surroundings System Surroundings System Energy Before reaction After reaction In this example, the energy of the reactants and products increases, while the energy of the surroundings decreases. In every case, however, the total energy does not change. Myers, Oldham, Tocci, Chemistry, 2004, page 41 Endothermic Reaction Reactant + Energy Product

68. Conservation of Energy in a Chemical Reaction Surroundings System Surroundings System Energy Before reaction After reaction In this example, the energy of the reactants and products decreases, while the energy of the surroundings increases. In every case, however, the total energy does not change. Myers, Oldham, Tocci, Chemistry, 2004, page 41 Exothermic Reaction Reactant Product + Energy

69. Direction of Heat Flow Surroundings ENDOthermic q sys > 0 EXOthermic q sys < 0 System Kotz, Purcell, Chemistry & Chemical Reactivity 1991, page 207 System H 2 O(s) + heat  H 2 O(l)melting H 2 O(l)  H 2 O(s) + heat freezing

70. Heating Curves Melting - PE  Solid - KE  Liquid - KE  Boiling - PE  Gas - KE  Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

71. Heating Curves Temperature ( o C) 40 20 0 -20 -40 -60 -80 -100 120 100 80 60 140 Time Melting - PE  Solid - KE  Liquid - KE  Boiling - PE  Gas - KE 

72. Heating Curves Temperature Change –change in KE (molecular motion) –depends on heat capacity Heat Capacity –energy required to raise the temp of 1 gram of a substance by 1°C –“Volcano” clip - –water has a very high heat capacity Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

73. Heating Curves Phase Change –change in PE (molecular arrangement) –temp remains constant Heat of Fusion (  H fus ) –energy required to melt 1 gram of a substance at its m.p. Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

74. Heating Curves Heat of Vaporization (  H vap ) –energy required to boil 1 gram of a substance at its b.p. –usually larger than  H fus …why? EX: sweating, steam burns, the drinking bird Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

75. Phase Diagrams Show the phases of a substance at different temps and pressures. Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

76. Calculating Energy Changes - Heating Curve for Water Temperature ( o C) 40 20 0 -20 -40 -60 -80 -100 120 100 80 60 140 Time  H = mol x  H fus  H = mol x  H vap Heat = mass x  t x C p, liquid Heat = mass x  t x C p, gas Heat = mass x  t x C p, solid

77. Calculating Energy Changes - Heating Curve for Water Temperature ( o C) 40 20 0 -20 -40 -60 -80 -100 120 100 80 60 140 Time  H = mol x C fus  H = mol x C vap  H = mass x  T x C p, liquid  H = mass x  T x C p, gas  H = mass x  T x C p, solid C p, gas = 1.87 J/g o C C p, liquid = 4.184 J/g o C C p, solid = 2.077 J/g o C C f, water = 333 J/g C v, water = 2256 J/g

78. Endothermic Reaction Energy + Reactants  Products +  H Endothermic Reaction progress Energy Reactants Products Activation Energy

79. Conservation of Mass …mass is converted into energy Hydrogen (H 2 ) H = 1.008 amu Helium (He) He = 4.004 amu FUSION 2 H 2  1 He + ENERGY 1.008 amu x 4 4.0032 amu = 4.004 amu + 0.028 amu This relationship was discovered by Albert Einstein E = mc 2 Energy= (mass) (speed of light) 2

80. Triple Point Plot LeMay Jr, Beall, Robblee, Brower, Chemistry Connections to Our Changing World, 1996, page 488 solid liquid gas melting freezing sublimation deposition vaporization condensation Temperature ( o C) Pressure (atm) 0.6 2.6

81. Liquid VaporSolid Normal melting point Normal boiling point 101.3 0.61 0.016 100 0 Temperature ( o C) Pressure (KPa) Triple point Triple Point Critical pressure Critical point Critical temperature 373.99 22,058

82. Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

83. Objectives - Matter Explain why mass is used as a measure of the quantity of matter. Describe the characteristics of elements, compounds, and mixtures. Solve density problems by applying an understanding of the concepts of density. Distinguish between physical and chemical properties and physical and chemical changes. Demonstrate an understanding of the law of conservation of mass by applying it to a chemical reaction.

84. Objectives - Energy Identify various forms of energy. Describe changes in energy that take place during a chemical reaction. Distinguish between heat and temperature. Solve calorimetry problems. Describe the interactions that occur between electrostatic charges.

85. Law of Conservation of Energy E after = E before 2 H 2 + O 2  2 H 2 O + energy +  + WOOF!

86. Law of Conservation of Energy ENERGY CO 2 + H 2 OC 2 H 2 + O 2 PE reactants PE products KE stopper heat, light, sound E after = E before 2 H 2 + O 2  2 H 2 O + energy +  + WOOF!

87. Law of Conservation of Energy ENERGY C 2 H 2 + O 2 PE reactants PE products KE stopper heat, light, sound E after = E before 2C 2 H 2 + 5O 2  4 CO 2 + 2H 2 O + energy Energy Changes

88. Heating Curves Temperature ( o C) 40 20 0 -20 -40 -60 -80 -100 120 100 80 60 140 Time Melting - PE  Solid - KE  Liquid - KE  Boiling - PE  Gas - KE 

89. Heating Curves  Temperature Change change in KE (molecular motion) depends on heat capacity  Heat Capacity energy required to raise the temp of 1 gram of a substance by 1°C “Volcano” clip - water has a very high heat capacity Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

90. Heating Curves  Phase Change change in PE (molecular arrangement) temp remains constant  Heat of Fusion (  H fus ) energy required to melt 1 gram of a substance at its m.p. Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

91. Heating Curves  Heat of Vaporization (  H vap ) energy required to boil 1 gram of a substance at its b.p. usually larger than  H fus …why?  EX: sweating, steam burns, the drinking bird Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

92. Phase Diagrams  Show the phases of a substance at different temps and pressures. Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem