1. States of Matter Ch.13 Section 1: The Nature of Gases Section 2: The Nature of Liquids Section 3: The Nature of Solids Section 4: Changes of State

2. Bell-Ringer DATE: 9/25/2014 OBJECTIVE: To log into Pearson Chem with your personal username and password. Please turn on your laptops and go to my classroom website. NHS Website, click on “Teacher Sites” Once on the Teacher Sites page, click on “Ms. Gray’s Classroom” Once on Ms. Gray’s Classroom, click on “My Resources” Once on the My Resources page, click on the image of your textbook. This should take you to a website called “SuccessNetPlus” Log-in with your username and password.

3. What does the word Kinetic Refer to? Kinetic energy – the energy an object has because of its motion. Section 13.1

4. Kinetic Theory  According to the kinetic theory, all matter consists of tiny particles that are in constant motion. PhET Simulation for States of Matter Basics

5. Kinetic Theory and a Model for Gases The particles in a gas are considered to be small, hard spheres with an insignificant volume. The motion of particles in a gas is rapid, constant, and random. All collisions between particles in a gas are perfectly elastic.

6. The particles in a gas are considered to be small, hard spheres with an insignificant volume. – Within a gas, the particles are relatively far apart compared with the distance between particles in a liquid or solid. – Between the particles, there is empty space. – No attractive or repulsive forces exist between the particles.

7. The motion of particles in a gas is rapid, constant, and random. – Gases fill their containers regardless of the shape and volume of the containers. – An uncontained gas can spread out into space without limit. Bromine molecule

8. The motion of particles in a gas is rapid, constant, and random. – The rapid, constant motion of particles in a gas causes them to collide with one another and with the walls of their container.

9. The motion of particles in a gas is rapid, constant, and random. – The particles travel in straight-line paths until they collide with another particle. – The particles change direction only when they rebound from collisions.

10. All collisions between particles in a gas are perfectly elastic. – During an elastic collision, kinetic energy is transferred without loss from one particle to another. – The total kinetic energy remains constant. Review Key Concepts again with simulation. PhET Simulation for States of Matter Basics

11. Describe an elastic collision between gas molecules. An elastic collision is one in which kinetic energy is transferred from one particle to another with no overall loss of kinetic energy.

12. How does kinetic theory explain gas pressure? Gas pressure results from the force exerted by a gas per unit surface area of an object. Gas pressure is the result of billions of rapidly moving particles in a gas simultaneously colliding with an object. An empty space with no particles and no pressure is called a vacuum.

13. Air Pressure  Air exerts pressure on Earth because gravity holds the particles in air within Earth’s atmosphere. The collisions of atoms and molecules in air with objects results in atmospheric pressure. Atmospheric pressure decreases as you climb a mountain because the density of Earth’s atmosphere decreases as the elevation increases.

15. Gas Pressure A barometer is a device that is used to measure atmospheric pressure. At sea level, air exerts enough pressure to support a 760-mm column of mercury. On top of Mount Everest, at 9000 m, the air exerts only enough pressure to support a 253-mm column of mercury.

16. When weather forecasters state that a low-pressure system is moving into your region, it usually means that a storm is coming. What do you think happens to the column of mercury in a barometer as a storm approaches? Why?

17.  One standard atmosphere (atm) is the pressure required to support 760 mm of mercury in a mercury barometer at 25°C. The numerical relationship among the three units is 1 atm = 760 mm Hg = 101.3 kPa. Recall that standard temperature and pressure (STP) are defined as a temperature of 0°C and a pressure of 101.3 kPa, or 1 atm. The SI unit of pressure is the pascal (Pa).

18. Converting between units of pressure A pressure gauge records a pressure of 450 kPa. Convert this measurement to a.atmospheres b.millimeters of mercury Sample Problem 13.1 Conversion factor: 1 atm = 760 mm Hg = 101.3 kPa.

19. 1. What pressure, in kilopascals and in atmospheres does a gas exert at 385 mm Hg? Converting between units of pressure Additional Problems

20. 2. The pressure at the top of Mount Everest is 33.7 kPa. Is that pressure greater or less than 0.25 atm? Converting between units of pressure Additional Problems

21. Agenda  Go over last night’s homework: Pressure Unit Conversions worksheet.  Complete notes on CH.13 Section.1  3 BINGO questions  In class assignment:  Read CH.13 Section. 1 in the textbook; pages 420-424.  Complete workbook pages #184-187.  Answer questions #3-8 in the text on page 424. DATE: 9/26/2014

22. 3. What pressure, in mm Hg and atm, does a sample of neon gas exert at 75.0 kPa? Converting between units of pressure Additional Problems

23. 4. What pressure, in mm Hg and kPa, does a sample of argon gas exert at 1.561 atm? Converting between units of pressure Additional Problems

24. What is the pressure in millimeters of mercury inside a vacuum? 0 mm Hg

25. Kinetic Energy & Temperature As a substance is heated, its particles absorb energy, some of which is stored within the particles. This stored portion of the energy, or potential energy, does not raise the temperature of the substance. The remaining absorbed energy does speed up the particles, that is, increases their kinetic energy. – This increase in kinetic energy results in an increase in temperature.

26.  As a substance is heated, the particles tend to move faster, and their average kinetic energy increases. Notice that the molecules at the higher temperature have a wider range of kinetic energies. As a substance cools, the particles tend to move more slowly, and their average kinetic energy decreases.

27. Which point on each curve represents the average kinetic energy? Compare the shapes of the curves for cold H 2 O and hot H 2 O. What would happen to the shape of the curve if the water temperature were even higher? Even lower?

28. Kinetic Energy & Temperature  Absolute zero (0 K, or –273.15 o C) is the temperature at which the motion of particles theoretically ceases.  STOP for Absolute Zero: PBS Nova film

29. Were you paying attention? 1.According to the kinetic theory, the particles in a gas A. are attracted to each other. B. are in constant random motion. C. have the same kinetic energy. D. have a significant volume.

30. Were you paying attention? 2.The pressure a gas exerts on another object is caused by A. the physical size of the gas particles. B. collisions between gas particles and the object. C. collisions between gas particles. D. the chemical composition of the gas.

31. Were you paying attention? 3.The average kinetic energy of the particles in a substance is directly proportional to the A. Fahrenheit temperature. B. Kelvin temperature. C. molar mass of the substance. D. Celsius temperature.

32. Were you paying attention? 4. What is the results of increasing the temperature of a gas sample? A. A decrease in the average kinetic energy of the sample B. No effect on the sample C. An increase in the average kinetic energy of the sample D. The particles slow down.

33. The Kinetic Molecular Theory Postulates  Gases are composed of many particles that behave like hard, spherical objects in a state of constant, random motion.  These particles move in a straight line until they collide with another particle or the walls of the container.  These particles are much smaller than the distance between particles, therefore the volume of a gas is mostly empty space and the volume of the gas molecule themselves is negligible.  There is no force of attraction between gas particles or between the particles and walls of the container.  Collisions between gas particles or collisions with the walls of the container are elastic. That is, none of the energy of the gas particles is lost in a collision

34. Bell Ringer  When brewing coffee, identify the solvent and the solute.  What factors may affect coffee brewing results?  The ratio of water-to-coffee  Particle size of the coffee beans  The temperature of the water  The amount of time water and coffee are in contact with each other  Why is coffee brewed with hot water?  Water is a better solvent at hot, or near-boiling temperatures. DATE: 9/30/2014

35.  Compare and contrast; what is the difference between evaporation and boiling? Bell Ringer DATE: 9/30/2014

36. Substances that can flow are referred to as fluids. A Model for Liquids Section 13.2 – The ability of gases and liquids to flow allows them to conform to the shape of their containers.

37. Indefinite shape; flows Fixed volume Almost incompressible Indefinite shape; flows Indefinite volume; takes the shape of its container Easily compressed Why are liquids not as easily compressible and gases are? According to kinetic theory, there are no attractions between the particles in a gas. The particles in a liquid are attracted to each other. - These intermolecular attractions keep the particles in a liquid close together

38. Indefinite shape; flows Fixed volume Almost incompressible Indefinite shape; flows Indefinite volume; takes the shape of its container Easily compressed  Liquids are much more dense than gases. Floats = less dense Sinks = more dense

39. Evaporation  The conversion of a liquid to a gas or vapor is called vaporization.  When this conversion occurs at the surface of a liquid that is not boiling, the process is called evaporation. In an open system, molecules that evaporate can escape from the system. In a closed system, the molecules collect as a vapor above the liquid. Some condense back into a liquid.

40. Evaporation During evaporation, only those molecules with a certain minimum kinetic energy can escape from the surface of the liquid. As evaporation occurs, the particles with the highest kinetic energy tend to escape first. Even some of the particles that do escape collide with molecules in the air and rebound back into the liquid.

41. Evaporation ► A liquid evaporates faster when heated. ► Heating the liquid increases the average kinetic energy of its particles. ► The added energy enables more particles to overcome the attractive forces keeping them in the liquid state. ► Evaporation is a cooling process

42. Vapor Pressure The evaporation of a liquid in a closed system differs from evaporation in an open system. When a partially filled container of liquid is sealed, some of the particles at the surface of the liquid vaporize. These particles collide with the walls of the sealed container, producing pressure. –A measure of the force exerted by a gas above a liquid is called vapor pressure.

43. Vapor Pressure Eventually, the number of particles condensing will equal the number of particles vaporizing. Over time, the number of particles entering the vapor increases and some of the particles condense and return to the liquid state. Liquid Vapor (gas) evaporation condensation

45. Vapor Pressure In a system at constant vapor pressure, a dynamic equilibrium exists between the vapor and the liquid. The system is in equilibrium because the rate of evaporation of liquid equals the rate of condensation of vapor.

46. Vapor Pressure Vapor Pressure and Temperature Change An increase in the temperature of a contained liquid increases the vapor pressure. This happens because the particles in the warmed liquid have increased kinetic energy. –More of the particles will reach the minimum kinetic energy necessary to escape the surface of the liquid.

47. Vapor Pressure Vapor Pressure and Temperature Change

48. Vapor Pressure The vapor pressure data indicates how volatile a given liquid is, or how easily it evaporates. Vapor Pressure and Temperature Change Vapor Pressure (in kPa) of Three Substances at Different Temperatures Substance0°C0°C20°C40°C60°C80°C100°C Water 0.61 2.33 7.37 19.92 47.34101.33 Ethanol 1.63 5.85 18.04 47.02108.34225.75 Diethyl ether 24.70 58.96122.80230.65399.11647.87

49. Vapor Pressure Vapor Pressure Measurements The vapor pressure of a liquid can be determined with a device called a manometer. 12.2 mm Hg or 1.63 kPa 43.9 mm Hg or 5.85 kPa Air at standard temperature and pressure Ethanol at 0°CEthanol at room temperature (20°C) Air Mercury Ethanol Mercury Ethanol Mercury The vapor pressure is equal to the difference in height of the mercury in the two arms of the U-tube.

50. Were you paying attention? In a sealed gas-liquid system at a constant temperature, eventually A. there will be no more evaporation. B. the rate of condensation decreases to zero. C. the rate of condensation exceeds the rate of evaporation. D. the rate of evaporation equals the rate of condensation.

51. Teacher Demo Vapor Pressure  Water vs. rubbing alcohol  Observe & infer which liquid has the greater vapor pressure at room temperature and explain their reasoning.

52. Boiling Point When a liquid is heated to a temperature at which particles throughout the liquid have enough kinetic energy to vaporize, the liquid begins to boil. Bubbles of vapor form throughout the liquid, rise to the surface, and escape into the air. The boiling point (bp) is the temperature at which the vapor pressure of the liquid is just equal to the external pressure on the liquid.

53. ► Why does food take less time to cook in a pressure cooker?  Why does it take longer to cook food in water at higher altitudes? Chemistry and You

54. Boiling Point & Pressure Changes  Because a liquid boils when its vapor pressure is equal to the external pressure, liquids don’t always boil at the same temperature. Because atmospheric pressure is lower at higher altitudes, boiling points decrease at higher altitudes.

55. Boiling Point and Pressure Changes Atmospheric pressure at the surface of water at 70°C is greater than its vapor pressure. Bubbles of vapor cannot form in the water, and it does not boil. At the boiling point, the vapor pressure is equal to the atmospheric pressure. Bubbles of vapor form in the water, and it boils. At higher altitudes, the atmospheric pressure is lower than it is at sea level. Thus, the water boils at a lower temperature. 101.3 kPa 34 kPa 70°C 100°C Sea Level Atop Mount Everest

56. Interpret Graphs At a lower external pressure, the boiling point decreases. At a higher external pressure, the boiling point increases.

57. Boiling is a cooling process close to evaporation  The vapor produced is at the same temperature as that of the boiling liquid. – Although the vapor has the same average kinetic energy as the liquid, its potential (or stored) energy is much higher. – Thus, a burn from steam is more severe than one from an equal mass of boiling water, even though they are both at the same temperature.

58. Normal Boiling Point  The is defined as the boiling point of a liquid at a pressure of 101.3 kPa. normal boiling point Normal Boiling Points of Several Substances SubstanceBoiling Point (°C) Carbon disulfide (CS 2 )46.0 Chloroform (CHCl 3 )61.7 Methanol (CH 4 O)64.7 Carbon tetrachloride (CCl 4 )76.8 Ethanol (C 2 H 6 O)78.5 Water (H 2 O) 100.0

59. Is the boiling point of water at the top of Mount McKinley (the highest point in North America) higher or lower than it is in Death Valley (the lowest point in North America)?  The boiling point of water decreases as altitude increases. Therefore, the boiling point of water is lower atop Mount McKinley than it is in Death Valley.

60. 1. In liquids, the attractive forces are A. very weak compared with the kinetic energies of the particles. B. strong enough to keep the particles confined to fixed locations in the liquid. C. strong enough to keep the particles from evaporating. D. strong enough to keep particles relatively close together. Were you paying attention?

61. 2. Which one of the following is a process that absorbs energy? A. freezing B. condensation C. evaporation D. solidifying Were you paying attention?

62. 3. In a sealed gas-liquid system at constant temperature, eventually with freezing A. there will be no more evaporation. B. the rate of condensation decreases to zero. C. the rate of condensation exceeds the rate of evaporation. D. the rate of evaporation equals the rate of condensation. Were you paying attention?

63. 4. Where must particles have enough kinetic energy to vaporize for boiling to occur? A. at the surface of the liquid B. at the bottom of the container C. along the sides of the container D. throughout the liquid Were you paying attention?

64. 5. The boiling point of a liquid A. increases at higher altitudes. B. decreases at higher altitudes. C. is the same at all altitudes. D. decreases as the pressure increases. Were you paying attention?

65. Bell-Ringer Please duplicate the graph to the right in your bell-ringer.  Identify if this is an endothermic or exothermic curve.  Identify on the curve where the heating of a solid, liquid, and gas occur.  Identify where the phase changes occur by the processes that occur there.  Identify whether the kinetic energy and potential energy is increase, decreasing, or remaining constant for each of the segments on the graph. DATE: 10/6/2014

66. Changes of State  http://www.pbs.org/wgbh/nova/physics/states-of-matter.html http://www.pbs.org/wgbh/nova/physics/states-of-matter.html Section 13.3 Section 13.4 The Nature of Solids  Students were instructed to just read the section and complete the workbook.  No critical information in section.  Students were instructed to just read the section, complete the workbook, and answer the textbook questions.  Only critical information was phase change diagram, of which the phase diagram packet was used for instruction. The phase diagram for H2O was explained, walking through labeling melting point, boiling point, triple point, critical point, equilibrium, what happens to temperature when pressure is increased and decreased, etc.