Chemistry• the study of matter  • its chemical and physical properties  • the chemical and physical changes it undergoes  ...
Why do you need to know       chemistry?public health   pharmaceutical industry        CHEMISTRY                          ...
Chemistry overlaps with many different disciplines.             +Bunny reproduction is biology!
Chemistry overlaps with many different disciplines.   But chemists study thehormonal changes that tell the   bunnies when ...
Chemistry overlaps with many different disciplines.Psychologists study how mice “learn”.
Chemistry overlaps with many different disciplines.   But chemists study theneurotransmitters responsible        for learn...
Chemistry overlaps with many different disciplines.     What happens when a bunny     baby crosses a road is physics.
Chemistry overlaps with many different disciplines.     What happens when a bunny     baby crosses a road is physics.
Chemistry overlaps with many different disciplines.  What happens to the bunny baby‟s body   in the hot summer sun is chem...
MAJOR AREAS OF CHEMISTRY• Biochemistry - the study of life at the  molecular level• Organic chemistry - the study of matte...
Chemistry uses the scientific method                  • How does something                    work?                  • Wha...
Experimental methods• Experiments produce DATA & RESULTS• DATA:  – Recorded observations or measurements     • Mass, Time,...
CHEMISTRYthe study of matter  and its changes      . . . but what is matter?
CHEMISTRY the study of matter   and its changes       Matter is “stuff ”(anything with mass and volume)
CHEMISTRY         the study of matter           and its changes    Which of these are matter?hammer     Q-tip      fear   ...
Classification of Matter• Pure substance - a substance that has only one  component• Mixture - a combination of two or mor...
Classification of Matter• Element - a pure substance that cannot be changed  into a simpler form of matter by any chemical...
Classification of Matter• Mixture - a combination of two or more pure substances in  which each substance retains its own ...
Classification of Matter• Which classes of matter are shown below?                  Homogeneous    Heterogeneous   compoun...
The Periodic Table of   the Elements
The Periodic Table of the Elements         We know that all “matter” is made up of         very, very, very tiny spheres c...
The Periodic Table of the Elements         We know that all “matter” is made up of         very, very, very tiny spheres c...
The Periodic Table of the Elements
The Periodic Table of the Elements
The Periodic Table of the Elements
The Periodic Table of the Elements       Table is usually displayed this way.             (it takes up less space)        ...
The Periodic Table of the Elements    Every kind of atom has a name and a “symbol.”
The Periodic Table of the Elements  All modern symbols are based on letter abbreviations                  Hydrogen (H)    ...
The Periodic Table of the Elements        Some symbols have two letters.            Scandium (Sc)                         ...
The Periodic Table of the Elements     Some symbols come from foreign languages.    Tungsten (W) -- „W‟ is from wolfram (G...
The Periodic Table of the Elements    Some types of atoms are very common in air!   nitrogen, oxygen, carbon, argon, neon,...
The Periodic Table of the Elements Some types of atoms are very common in dirt and rocks!    oxygen, silicon, aluminum, ir...
The Periodic Table of the Elements   Some types of atoms are very common in stars! hydrogen, helium, carbon, oxygen, neon,...
The Periodic Table of the ElementsSome types of atoms are very common in human bodies!oxygen, carbon, hydrogen, nitrogen, ...
The Periodic Table of the Elements                     18 columns              (Columns are called groups)       1 2 3 4 ....
The Periodic Table of the Elements           This is group 13.
The Periodic Table of the Elements                  7 rows          (Rows are called periods)     1     2     3     4     ...
The Periodic Table of the Elements            This is period 4.
The Periodic Table of the Elements     alkali metals      (Group 1)
The Periodic Table of the Elements alkaline earth metals       (Group 2)
The Periodic Table of the Elements      halogens     (Group 17)
The Periodic Table of the Elements  noble gases or “inert” gases          (Group 18)                         All of the at...
Consider these three halogens:                           http://www.an.psu.edu/rxg1/pt1999/halogens.html
Consider these three halogens:  •All smell like a swimming pool.  •All produce colored vapors.  •All are poisonous.  •All ...
Consider these three alkali metals:   Lithium (Li)  Sodium (Na) Potassium (K)
Consider these three alkali metals: •All are shiny, soft solids when pure. •All melt at very low temperatures.Lithium mp =...
Consider these three alkali metals: •All are shiny, soft solids when pure. •All melt at very low temperatures. •All react ...
The Periodic Table of the Elements Metals Non-metals Metalloids or semimetalsHydrogenis an odd-   ball!
The Periodic Table of the Elements Metals are . . .   •Lustrous          •Ductile   •Malleable         •Conductors of   •P...
The Periodic Table of the Elements Nonmetals are . . .   •Not lustrous             •Not ductile   •Not malleable          ...
Classification & Behavior of Matter• Properties of Matter  – Physical  – Chemical  What are some examples of properties of...
Chemical Properties & Change• Property - result in a change in composition  and can be observed only through a chemical  r...
Physical Properties & Change• Property - is observed without changing the  composition or identity of a substance• Change ...
Separation by Physical PropertiesMagnetic iron is separated from other nonmagnetic substances, such as sand. This property...
Three States of Water(a) Solid       (b) Liquid   (c) Gas
Three States of Matter• gas - particles widely separated, no  definite shape or volume solid• liquid - particles closer to...
Comparison of states of matter Solid       Liquid           Gas ordered    not ordered    not orderedcondensed   condensed...
Solid Properties
Solids are . . .•Not compressible•Organized•Don’t take the shape of their container!But solids are more complex than this!
All solids are considered by chemists to  be either crystalline or amorphous.Crystalline:          at the atomiclevel, mat...
All solids are considered by chemists to  be either crystalline or amorphous.Crystalline:          at the atomiclevel, mat...
Gases        http://www.btinternet.com/~digital.wallpapers/hot_air_balloon.j
Some Gaseous Odds and Ends Gases have very low densitiesN2 (s)   d = 1.03 g/mLN2 (l)   d = 0.808 g/mL (78%)N2 (g)   d = 0...
Some Gaseous Odds and Ends Gases readily expand to fill their container    (implies that gas molecules are moving rapidly)
Some Gaseous Odds and Ends Gases are readily compressible        (implied by “mostly empty space”)
Some Gaseous Odds and Ends Gases are readily compressible        (Liquids and solids are already                 compress...
Some Gaseous Odds and Ends And they “spring” back!       (implies that gases exert “pressure”)
Some Gaseous Odds and EndsGases exert “pressure” because gas  molecules collide with container.                       Usua...
Some Gaseous Odds and EndsGases exert “pressure” because gas  molecules collide with container.                        usu...
Some Gaseous Odds and EndsGases exert “pressure” because gas  molecules collide with container.    known as a “Pascal” (Pa...
Some Gas Problems Convert 34 psi to Pa.                 101,325 Pa = 14.7 psi
What is blood pressure?                          The liquid inside your                             blood vessels is      ...
What is blood pressure?                          The liquid inside your                             blood vessels is      ...
In 1662, Robert Boyle discovered an inverserelationship between the pressure exerted           by a gas and its volume.   ...
In 1662, Robert Boyle discovered an inverserelationship between the pressure exerted           by a gas and its volume.   ...
In 1662, Robert Boyle discovered an inverse relationship between the pressure exerted            by a gas and its volume.E...
In 1662, Robert Boyle discovered an inverserelationship between the pressure exerted           by a gas and its volume. th...
using Boyle’s lawWhen atmospheric pressure = 14.9 psi, a sample of airhas a volume of 30 mL. What will the volume of the a...
using Boyle’s lawWhen atmospheric pressure = 14.9 psi, a sample of airhas a volume of 30 mL. What will the volume of the a...
using Boyle’s lawWhen atmospheric pressure = 14.9 psi, a sample of airhas a volume of 30 mL. What will the volume of the a...
using Boyle’s lawWhen atmospheric pressure = 14.9 psi, a sample of airhas a volume of 30 mL. What will the volume of the a...
using Boyle’s law When atmospheric pressure = 14.9 psi, a sample of air has a volume of 30 mL. What will the volume of the...
In 1787, Jacques Charles discovered that the    temperature and volume of a gas are                proportional     http:/...
In 1787, Jacques Charles discovered that the    temperature and volume of a gas are                proportional           ...
In 1787, Jacques Charles discovered that the     temperature and volume of a gas are                 proportional         ...
If temperature is in degrees Kelvin, we have the following:                V                      Constant                ...
using charles’ law  A sample of steam at 100 C has a volume of 240 mL.What will the new volume be if the steam is cooled t...
using charles’ law  A sample of steam at 100 C has a volume of 240 mL.What will the new volume be if the steam is cooled t...
using charles’ law   A sample of steam at 100 C has a volume of 240 mL. What will the new volume be if the steam is cooled...
Combined Gas Law• Derived from a combination of Boyle’s  law and Charles’s law• Change involving volume, pressure, and  te...
Using the Combined Gas Law• Calculate the volume of N2 resulting when  0.100 L of the gas is heated from 300. K to  350. K...
Many of the “most important” gases aren’t    pure, but are actually mixtures.
What is the composition of air?For every 1,000,000 “air” molecules, . . .             780,810    N2 molecules             ...
What is the composition of air?In urban areas, the following pollutantmolecules can be fairly abundant:                   ...
Consider a Rain Forest in Belize.             Costa Rican rainforest      http://www5.worldisround.com/photos/5/282/505_o....
Consider a Rain Forest in Belize.             Costa Rican rainforestAt 86 F and 95% humidity, we have:            749,730 ...
The amount of H2O in air is highly dependent        on weather and geography.Consider Vostok, Antarctica:     http://saleg...
The amount of H2O in air is highly dependent        on weather and geography.Consider Vostok, Antarctica:At -76 F and 34% ...
The amount of H2O in air is highly dependent       on weather and geography.    Whether a gas is pure or a mixture, it   s...
Why should you care?
Breathing air that isroughly 20% O2 means   that 80% of themolecular collisions inyour lungs are useless.
Breathing 100% O2increases the “partial   pressure” of O2
Liquids are . . .•Not compressible•Not organizedLiquids have . . .   Viscosity         Vapor PressureSurface Tension      ...
The Properties of Most Liquids Can be                       Rationalized        in Terms of Their Intermolecular Forces   ...
Liquids have a “Skin”!Because it can hydrogen-bond, water’s     skin is particularly tough!
Liquids have a “Skin”!  Liquids with weak intermolecular attractive        forces have less surface tension.
Liquids have a “Skin”! Water’s high surface tension causes it    to “bead up” into large drops.   Liquids with weak interm...
Liquids have a viscosity     Which pours more   easily, a jar of marbles  or a jar of gummy bears?
Liquids have a viscosity     Which pours more   easily, gummy bears or      gummy worms?
Liquids have a viscosity  Long, flexible molecules         with strong  intermolecular forces are        most viscous.
Liquids have a vapor pressure  What happens when a liquid is poured into a perfectly     empty container and the container...
Liquids have a vapor pressure     Some of the molecules at the surface evaporate.
Liquids have a vapor pressure But the number of gas molecules only increases to a point.
Liquids have a vapor pressure           Some of the gas molecules bump back      into the liquid layer, slow down, and “re...
Liquids have a vapor pressure When the number leaving the liquid equals the number re-     entering the liquid, we have an...
Liquids have a vapor pressure    When equilibrium is reached, molecules with strong      intermolecular attractive forces ...
Liquids have a vapor pressure    When equilibrium is reached, molecules with weak     intermolecular attractive forces loo...
What is melting?   What is subliming?
“Deposition” is the opposite of sublimation.
Chem115 unit1
Chem115 unit1
Chem115 unit1
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Chem115 unit1

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Chemistry: Stuff & measuring it

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Chem115 unit1

  1. 1. Chemistry• the study of matter • its chemical and physical properties • the chemical and physical changes it undergoes • the energy changes that accompany those processes• Most changes either require energy or produce energy• This class will focus on the changes that happen in living systems
  2. 2. Why do you need to know chemistry?public health pharmaceutical industry CHEMISTRY food sciencemedical practitioners forensic sciences
  3. 3. Chemistry overlaps with many different disciplines. +Bunny reproduction is biology!
  4. 4. Chemistry overlaps with many different disciplines. But chemists study thehormonal changes that tell the bunnies when to mate! +Bunny reproduction is biology!
  5. 5. Chemistry overlaps with many different disciplines.Psychologists study how mice “learn”.
  6. 6. Chemistry overlaps with many different disciplines. But chemists study theneurotransmitters responsible for learning! Psychologists study how mice “learn”.
  7. 7. Chemistry overlaps with many different disciplines. What happens when a bunny baby crosses a road is physics.
  8. 8. Chemistry overlaps with many different disciplines. What happens when a bunny baby crosses a road is physics.
  9. 9. Chemistry overlaps with many different disciplines. What happens to the bunny baby‟s body in the hot summer sun is chemistry!
  10. 10. MAJOR AREAS OF CHEMISTRY• Biochemistry - the study of life at the molecular level• Organic chemistry - the study of matter containing carbon and hydrogen• Inorganic chemistry - the study of matter containing elements, not organic• Analytic chemistry - analyze matter to determine identity and composition• Physical chemistry - attempts to explain the way matter behaves
  11. 11. Chemistry uses the scientific method • How does something work? • What is the “truth” about how something works? • Does my data support my hypothesis? • Do I need to change my hypothesis?
  12. 12. Experimental methods• Experiments produce DATA & RESULTS• DATA: – Recorded observations or measurements • Mass, Time, Temp, volume, energy• RESULTS: – Outcome of experiment – Conclusions drawn from observations – Usually several pieces of data form a result
  13. 13. CHEMISTRYthe study of matter and its changes . . . but what is matter?
  14. 14. CHEMISTRY the study of matter and its changes Matter is “stuff ”(anything with mass and volume)
  15. 15. CHEMISTRY the study of matter and its changes Which of these are matter?hammer Q-tip fear paper bag beauty blood talent acorn air gravity
  16. 16. Classification of Matter• Pure substance - a substance that has only one component• Mixture - a combination of two or more pure substances in which each substance retains its own identity, not undergoing a chemical reaction
  17. 17. Classification of Matter• Element - a pure substance that cannot be changed into a simpler form of matter by any chemical reaction• Compound - a substance resulting from the combination of two or more elements in a definite, reproducible way, in a fixed ratio
  18. 18. Classification of Matter• Mixture - a combination of two or more pure substances in which each substance retains its own identity• Homogeneous - uniform composition, particles well mixed, thoroughly intermingled• Heterogeneous – nonuniform composition, random placement
  19. 19. Classification of Matter• Which classes of matter are shown below? Homogeneous Heterogeneous compound mixture mixture
  20. 20. The Periodic Table of the Elements
  21. 21. The Periodic Table of the Elements We know that all “matter” is made up of very, very, very tiny spheres called atoms.Each square in this table represents a different kind of atom. There are over 114 different kinds of atoms.
  22. 22. The Periodic Table of the Elements We know that all “matter” is made up of very, very, very tiny spheres called atoms.Each square in this table represents a different kind of atom.Table organization is based on each atom‟s makeup and thesimilarities of the properties of the various kinds of atoms.
  23. 23. The Periodic Table of the Elements
  24. 24. The Periodic Table of the Elements
  25. 25. The Periodic Table of the Elements
  26. 26. The Periodic Table of the Elements Table is usually displayed this way. (it takes up less space) We won‟t discuss any of these elements in Physiological Chemistry
  27. 27. The Periodic Table of the Elements Every kind of atom has a name and a “symbol.”
  28. 28. The Periodic Table of the Elements All modern symbols are based on letter abbreviations Hydrogen (H) Every symbol starts Oxygen (O) with a capital letter. Iodine (I)
  29. 29. The Periodic Table of the Elements Some symbols have two letters. Scandium (Sc) First letter is capital Bismuth (Bi) and second is lower case. Neon (Ne)
  30. 30. The Periodic Table of the Elements Some symbols come from foreign languages. Tungsten (W) -- „W‟ is from wolfram (German) Sodium (Na) -- „Na‟ is from natrium (Latin) Antimony (Sb) -- „Sb‟ is from Stibium (Latin)
  31. 31. The Periodic Table of the Elements Some types of atoms are very common in air! nitrogen, oxygen, carbon, argon, neon, helium
  32. 32. The Periodic Table of the Elements Some types of atoms are very common in dirt and rocks! oxygen, silicon, aluminum, iron, calcium, sodium
  33. 33. The Periodic Table of the Elements Some types of atoms are very common in stars! hydrogen, helium, carbon, oxygen, neon, magnesium
  34. 34. The Periodic Table of the ElementsSome types of atoms are very common in human bodies!oxygen, carbon, hydrogen, nitrogen, calcium, phosphorus
  35. 35. The Periodic Table of the Elements 18 columns (Columns are called groups) 1 2 3 4 . . . . . . . . . . . . . . . . . . . . . . . . . 16 17 18
  36. 36. The Periodic Table of the Elements This is group 13.
  37. 37. The Periodic Table of the Elements 7 rows (Rows are called periods) 1 2 3 4 5 6 7
  38. 38. The Periodic Table of the Elements This is period 4.
  39. 39. The Periodic Table of the Elements alkali metals (Group 1)
  40. 40. The Periodic Table of the Elements alkaline earth metals (Group 2)
  41. 41. The Periodic Table of the Elements halogens (Group 17)
  42. 42. The Periodic Table of the Elements noble gases or “inert” gases (Group 18) All of the atoms in a group have similar properties.
  43. 43. Consider these three halogens: http://www.an.psu.edu/rxg1/pt1999/halogens.html
  44. 44. Consider these three halogens: •All smell like a swimming pool. •All produce colored vapors. •All are poisonous. •All react rapidly with sodium to give edible salts.Groups in the periodic table are comprised of elements with similar properties. http://www.an.psu.edu/rxg1/pt1999/halogens.html
  45. 45. Consider these three alkali metals: Lithium (Li) Sodium (Na) Potassium (K)
  46. 46. Consider these three alkali metals: •All are shiny, soft solids when pure. •All melt at very low temperatures.Lithium mp = 181oCSodium mp = 98oCPotassium mp = 63oC
  47. 47. Consider these three alkali metals: •All are shiny, soft solids when pure. •All melt at very low temperatures. •All react violently with water. http://www.westga.edu/~chem/courses/desc.inorg/490Jan14/sld009.htm
  48. 48. The Periodic Table of the Elements Metals Non-metals Metalloids or semimetalsHydrogenis an odd- ball!
  49. 49. The Periodic Table of the Elements Metals are . . . •Lustrous •Ductile •Malleable •Conductors of •Prone to losing electricity electrons •Lower Left of periodic table
  50. 50. The Periodic Table of the Elements Nonmetals are . . . •Not lustrous •Not ductile •Not malleable •Not conductors of •Often prone to gaining electricity electrons •Upper Right of table
  51. 51. Classification & Behavior of Matter• Properties of Matter – Physical – Chemical What are some examples of properties of matter?• States of Matter – Solid – Liquid – Gas • Gas Laws
  52. 52. Chemical Properties & Change• Property - result in a change in composition and can be observed only through a chemical reaction• Reaction (chemical change) - a process of rearranging, removing, replacing, or adding atoms to produce new substances hydrogen + oxygen  water reactants products
  53. 53. Physical Properties & Change• Property - is observed without changing the composition or identity of a substance• Change - produces a recognizable difference in the appearance of a substance without causing any change in its composition or identity - conversion from one physical state to another - melting an ice cube
  54. 54. Separation by Physical PropertiesMagnetic iron is separated from other nonmagnetic substances, such as sand. This property is used as a large-scale process in the recycling industry.
  55. 55. Three States of Water(a) Solid (b) Liquid (c) Gas
  56. 56. Three States of Matter• gas - particles widely separated, no definite shape or volume solid• liquid - particles closer together, definite volume but no definite shape• solid - particles are very close together, define shape and definite volume
  57. 57. Comparison of states of matter Solid Liquid Gas ordered not ordered not orderedcondensed condensed not condensed
  58. 58. Solid Properties
  59. 59. Solids are . . .•Not compressible•Organized•Don’t take the shape of their container!But solids are more complex than this!
  60. 60. All solids are considered by chemists to be either crystalline or amorphous.Crystalline: at the atomiclevel, material is highly organized and has arepeating pattern of particlesAmorphous: at the atomic level, materialappears randomly thrown together and nopatterns are present.
  61. 61. All solids are considered by chemists to be either crystalline or amorphous.Crystalline: at the atomiclevel, material is highly organized and has arepeating pattern of particles Ionic Solids Molecular Solids Metallic Solids Covalent Solids
  62. 62. Gases http://www.btinternet.com/~digital.wallpapers/hot_air_balloon.j
  63. 63. Some Gaseous Odds and Ends Gases have very low densitiesN2 (s) d = 1.03 g/mLN2 (l) d = 0.808 g/mL (78%)N2 (g) d = 0.00125 g/mL (0.12%) (implied by “mostly empty space”)
  64. 64. Some Gaseous Odds and Ends Gases readily expand to fill their container (implies that gas molecules are moving rapidly)
  65. 65. Some Gaseous Odds and Ends Gases are readily compressible (implied by “mostly empty space”)
  66. 66. Some Gaseous Odds and Ends Gases are readily compressible (Liquids and solids are already compressed)
  67. 67. Some Gaseous Odds and Ends And they “spring” back! (implies that gases exert “pressure”)
  68. 68. Some Gaseous Odds and EndsGases exert “pressure” because gas molecules collide with container. Usually “pounds” or Newtons force Pressure Area Usually in2 or m2 pounds Newtons in 2 m2
  69. 69. Some Gaseous Odds and EndsGases exert “pressure” because gas molecules collide with container. usually abbreviated as “psi” pounds Newtons in 2 m2
  70. 70. Some Gaseous Odds and EndsGases exert “pressure” because gas molecules collide with container. known as a “Pascal” (Pa) pounds Newtons in 2 m2
  71. 71. Some Gas Problems Convert 34 psi to Pa. 101,325 Pa = 14.7 psi
  72. 72. What is blood pressure? The liquid inside your blood vessels is compressed by the elastic nature of the vessel walls. Your blood pressure is usually 80 mm Hg greater than the atmospheric pressure
  73. 73. What is blood pressure? The liquid inside your blood vessels is compressed by the elastic nature of the vessel walls. When your heart contracts, the pressure goes up even more! . . . Perhaps to 120 mm Hg greater than atmospheric!
  74. 74. In 1662, Robert Boyle discovered an inverserelationship between the pressure exerted by a gas and its volume. http://elementy.ru/images/eltbio/boyle_robert_180.jpg
  75. 75. In 1662, Robert Boyle discovered an inverserelationship between the pressure exerted by a gas and its volume. 1 atm 2 atm 4 atm (As long as the temp was kept the same)
  76. 76. In 1662, Robert Boyle discovered an inverse relationship between the pressure exerted by a gas and its volume.Examine his data: 20 mL 1 atm = 20 mL.atm 10 mL 2 atm = 20 mL.atm 5 mL 4 atm = 20 mL.atmIn other words . . . P V = constant
  77. 77. In 1662, Robert Boyle discovered an inverserelationship between the pressure exerted by a gas and its volume. this is known as Boyle’s law P V = constant
  78. 78. using Boyle’s lawWhen atmospheric pressure = 14.9 psi, a sample of airhas a volume of 30 mL. What will the volume of the airsample be when atmospheric pressure drops to 14.5 psi?first, let’s find the constant: 14.9psi 30mL = 447 psi.mL P V = constant
  79. 79. using Boyle’s lawWhen atmospheric pressure = 14.9 psi, a sample of airhas a volume of 30 mL. What will the volume of the airsample be when atmospheric pressure drops to 14.5 psi?Now, use the constant to find the new volume: 14.9psi 30mL = 447 psi.mL 14.5psi V = 447 psi.mL
  80. 80. using Boyle’s lawWhen atmospheric pressure = 14.9 psi, a sample of airhas a volume of 30 mL. What will the volume of the airsample be when atmospheric pressure drops to 14.5 psi?Now, use the constant to find the new volume: 14.5psi V = 447 psi.mL
  81. 81. using Boyle’s lawWhen atmospheric pressure = 14.9 psi, a sample of airhas a volume of 30 mL. What will the volume of the airsample be when atmospheric pressure drops to 14.5 psi?Now, use the constant to find the new volume: 14.5psi V = 447 psi.mL 447 psi ×mL V 31mL 14.5 psi
  82. 82. using Boyle’s law When atmospheric pressure = 14.9 psi, a sample of air has a volume of 30 mL. What will the volume of the air sample be when atmospheric pressure drops to 14.5 psi?We often see Boyle’s law written as P1V1 = P2V2P1 = 14.9psi 14.9psi 30mL = 14.5psi V2V1 = 30mLP2 = 14.5psi V2 = 31mLV2 = ?
  83. 83. In 1787, Jacques Charles discovered that the temperature and volume of a gas are proportional http://content.answers.com/main/content/wp/en-commons/thumb/b/b7/250px- Jacques-Charles_Dupont_de_LEure.jpg
  84. 84. In 1787, Jacques Charles discovered that the temperature and volume of a gas are proportional ice bath at 0 C
  85. 85. In 1787, Jacques Charles discovered that the temperature and volume of a gas are proportional boiling water at 100 C20 mL of a gas at 0 C will occupy 27.3 mL at 100 C (as long as atmospheric pressure isn’t changed)
  86. 86. If temperature is in degrees Kelvin, we have the following: V Constant T this is known as charles’ law V1 V2 We often see Charles’ law written as = T1 T2
  87. 87. using charles’ law A sample of steam at 100 C has a volume of 240 mL.What will the new volume be if the steam is cooled to 0 C?first, let’s convert our temps to kelvin: 100C + 273 = 373K
  88. 88. using charles’ law A sample of steam at 100 C has a volume of 240 mL.What will the new volume be if the steam is cooled to 0 C?first, let’s convert our temps to kelvin: 100C + 273 = 373K 0C + 273 = 273K
  89. 89. using charles’ law A sample of steam at 100 C has a volume of 240 mL. What will the new volume be if the steam is cooled to 0 C? first, let’s convert our temps to kelvin: 100C + 273 = 373K 0C + 273 = 273KV1 = 240 mLT1 = 373K 240 mL V2V2 = ? = V2 = 176 mL 373K 273KT2 = 273K
  90. 90. Combined Gas Law• Derived from a combination of Boyle’s law and Charles’s law• Change involving volume, pressure, and temperature simultaneously PiVi Pf V f = Ti Tf
  91. 91. Using the Combined Gas Law• Calculate the volume of N2 resulting when 0.100 L of the gas is heated from 300. K to 350. K at 1.00 atm PiVi Pf V f• What do we know? = Ti Tf – Pi = 1.00 atm Pf = 1.00 atm – Vi = 0.100 L Vf = ? L – Ti = 300. K Tf = 350. K• Vf = ViTf / Ti this is valid as Pi = Pf• Vf = (0.100 L)(350. K) / 300. K = 0.117 L
  92. 92. Many of the “most important” gases aren’t pure, but are actually mixtures.
  93. 93. What is the composition of air?For every 1,000,000 “air” molecules, . . . 780,810 N2 molecules 209,480 O2 molecules 9,340 Ar atoms 345 CO2 molecules 18 Ne atoms 5 He atoms 2 CH4 molecules This is only true of dry, nonpolluted air.
  94. 94. What is the composition of air?In urban areas, the following pollutantmolecules can be fairly abundant: CO molecules NO molecules NO2 molecules SO2 molecules O3 molecules http://www.photo.net/photo/pcd0222/los-angeles-downtown-45.4.jpg
  95. 95. Consider a Rain Forest in Belize. Costa Rican rainforest http://www5.worldisround.com/photos/5/282/505_o.jpg
  96. 96. Consider a Rain Forest in Belize. Costa Rican rainforestAt 86 F and 95% humidity, we have: 749,730 N2 molecules 201,140 O2 molecules Water can be the 3rd most 39,810 H2O molecules abundant 8,970 Ar atoms gas in air! 330 CO2 molecules 17 Ne atoms 3 He atoms http://www5.worldisround.com/photos/5/282/505_o.jpg
  97. 97. The amount of H2O in air is highly dependent on weather and geography.Consider Vostok, Antarctica: http://salegos-scar.montana.edu/images/Vostok%20Station.JPG
  98. 98. The amount of H2O in air is highly dependent on weather and geography.Consider Vostok, Antarctica:At -76 F and 34% humidity, we have: 780,810 N2 molecules 209,480 O2 molecules 9,340 Ar atoms 345 CO2 molecules 18 Ne atoms 4 He atoms 3 H2O molecules http://salegos-scar.montana.edu/images/Vostok%20Station.JPG
  99. 99. The amount of H2O in air is highly dependent on weather and geography. Whether a gas is pure or a mixture, it still oBeys Boyle’s law and charles’ law However, in a mixture of gases, the total pressure equals the sum of the pressures due to each component http://salegos-scar.montana.edu/images/Vostok%20Station.JPG
  100. 100. Why should you care?
  101. 101. Breathing air that isroughly 20% O2 means that 80% of themolecular collisions inyour lungs are useless.
  102. 102. Breathing 100% O2increases the “partial pressure” of O2
  103. 103. Liquids are . . .•Not compressible•Not organizedLiquids have . . . Viscosity Vapor PressureSurface Tension Density
  104. 104. The Properties of Most Liquids Can be Rationalized in Terms of Their Intermolecular Forces Liquids have a surface tension (an edge effect)Compare the attractiveforces these molecules have for their neighbors!
  105. 105. Liquids have a “Skin”!Because it can hydrogen-bond, water’s skin is particularly tough!
  106. 106. Liquids have a “Skin”! Liquids with weak intermolecular attractive forces have less surface tension.
  107. 107. Liquids have a “Skin”! Water’s high surface tension causes it to “bead up” into large drops. Liquids with weak intermolecular attractive forces have smaller drops.
  108. 108. Liquids have a viscosity Which pours more easily, a jar of marbles or a jar of gummy bears?
  109. 109. Liquids have a viscosity Which pours more easily, gummy bears or gummy worms?
  110. 110. Liquids have a viscosity Long, flexible molecules with strong intermolecular forces are most viscous.
  111. 111. Liquids have a vapor pressure What happens when a liquid is poured into a perfectly empty container and the container is sealed?
  112. 112. Liquids have a vapor pressure Some of the molecules at the surface evaporate.
  113. 113. Liquids have a vapor pressure But the number of gas molecules only increases to a point.
  114. 114. Liquids have a vapor pressure Some of the gas molecules bump back into the liquid layer, slow down, and “re-stick”.
  115. 115. Liquids have a vapor pressure When the number leaving the liquid equals the number re- entering the liquid, we have an “equilibrium”.
  116. 116. Liquids have a vapor pressure When equilibrium is reached, molecules with strong intermolecular attractive forces look like this.
  117. 117. Liquids have a vapor pressure When equilibrium is reached, molecules with weak intermolecular attractive forces look like this.
  118. 118. What is melting? What is subliming?
  119. 119. “Deposition” is the opposite of sublimation.

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