States of Matter Changes of State

1. States of Matter & Changes of State Unit III

2. Phases of Matter The three phases of matter (solids, liquids, and gases) have different properties

3. Physical State (Phase) The structure and arrangement of particles and their interactions determine the physical state of a substance at a given temperature and pressure

4. Properties of Solids Regular geometric pattern in the arrangement of the molecules called a crystal lattice Molecules are close together and vibrate in place Molecules do not move from place to place Solids are not compressible Definite shape and definite volume

5. Properties of Liquids Molecules can move around (fluid) Molecules are farther apart than in a solid Liquids take the shape of their container Not compressible No definite shape but do have definite volume The forces of attraction between the molecules are weaker in a liquid than they are in a solid

6. Properties of Gases Molecules fill their container (spread out) Molecules are very far apart Molecules move in straight lines until they hit something (another molecule or wall of the container) No definite shape and no definite volume The forces of attraction between the molecules are very weak.

7. Regents Question: 08/02 #16 Which statement correctly describes a sample of gas confined in a sealed container? (1) It always has a definite volume, and it takes the shape of the container. (2) It takes the shape and the volume of any container in which it is confined. (3) It has a crystalline structure. (4) It consists of particles arranged in a regular geometric pattern.

8. Regents Question: 06/02 #12 Which 5.0-milliliter sample of NH3 will take the shape of and completely fill a closed 100.0-milliliter container? (1) NH3 (s) (3) NH3 (g) (2) NH3 (l) (4)NH3 (aq)

9. Regents Question: 06/03 #16 In which material are the particles arranged in a regular geometric pattern? (1) CO2 (g) (2) NaCl (aq) (3) H2O (l) (4) C12H22O11 (s)

10. Pure Substances A pure substance (element or compound) has a constant composition and constant properties throughout a given sample, and from sample to sample All pure substances are homogeneous

11. Phases of Matter Worksheet Directions: Complete the worksheet to the best of your ability. Turn in finished worksheet! If you do not finish it in class you must finish it as homework and submit the finished worksheet at the beginning of class tomorrow.

12. Phase Changes

13. Regents Question: 06/03 #17 Which change is exothermic? (1) freezing of water (2) melting of iron (3) vaporization of ethanol (4) sublimation of iodine

14. Heating Curve (? KE & ?PE)

15. Energy and phase changes AB – solid warms up (KE=? & PE=Constant) BC – solid melts (KE=Constant & PE=?) CD – liquid warms up (KE=? & PE=Constant) DE – liquid boils (KE=Constant & PE=?) EF – gas warms up (KE=? & PE=Constant)

16. Plotting a Cooling Curve Lab #7

17. Regents Question: 06/02 #28 As ice melts at standard pressure, its temperature remains at 0°C until it has completely melted. Its potential energy (1) decreases (2) increases (3) remains the same

18. Regents Question: 08/02 #54 A sample of water is heated from a liquid at 40°C to a gas at 110°C. The graph of the heating curve is shown in your answer booklet. a On the heating curve diagram provided in your answer booklet, label each of the following regions: Liquid, only Gas, only Phase change

19. Regents Question: cont’d b For section QR of the graph, state what is happening to the water molecules as heat is added. c For section RS of the graph, state what is happening to the water molecules as heat is added.

20. Regents Question: 01/02 #47 What is the melting point of this substance? (1) 30°C (3) 90°C (2) 55°C (4) 120°C

21. Heating Curve Worksheet Directions: Complete the worksheet to the best of your ability. Turn in finished worksheet! If you do not finish it in class you must finish it as homework and submit the finished worksheet at the beginning of class tomorrow.

22. Physical Change Heat Calculations The quantity of energy absorbed or released during a phase change can be calculated using the Heat of Fusion or Heat of Vaporization Melting (fusion) or freezing (solidification) Q=mHf (Hf is the heat of fusion for H2O: 334 J/g) Boiling (vaporization) or condensing Q=mHv (Hv is the heat of vaporization for H2O: 2260 J/g) Hf and Hv are given in Table B – m is grams of H2O

23. Physical Change Heat Calculations Heat is transferred to different materials at different rates The specific heat capacity (C) determines the rate at which heat will be absorbed The specific heat capacity for water is 4.18J/g•oC The quantity of heat absorbed (Q) can be calculated by: Q=mC?T m = mass ?T = change in temperature = Tf – Ti

24. Regents Question: 08/02 #24 In which equation does the term “heat” represent heat of fusion? (1) NaCl(s) + heat ? NaCl(l) (2) NaOH(aq) + HCl(aq) ? NaCl(aq) + H2O(l)+ heat (3) H2O(l)+ heat ? H2O(g) (4) H2O(l)+ HCl(g) ?H3O+(aq) + Cl –(aq) + heat Fusion refers to melting!

25. Melting Point The temperature at which a liquid and a solid are in equilibrium The melting point for ice is 0ºC The melting point of a substance is the same as its freezing point

26. Regents Question: 08/02 #5 Given the equation: H2O(s) H2O(l) At which temperature will equilibrium exist when the atmospheric pressure is 1 atm? (1) 0 K (3) 273 K (2) 100 K (4) 373 K K=oC + 273

27. Regents Question: 08/02 #18 The solid and liquid phases of water can exist in a state of equilibrium at 1 atmosphere of pressure and a temperature of (1) 0°C (3) 273°C (2) 100°C (4) 373°C

28. Regents Question: 06/03 #41 The freezing point of bromine is (1) 539°C (2) –539°C (3) 7°C (4) –7°C See Table S Melting point is the same as freezing point Convert K to C (K=C+273)

29. Calculating Joules No Phase Change & Calculating Phase Change Joules Worksheets Directions: Complete the worksheets to the best of your ability. Make sure all calculations are to the correct number of significant figures. Turn in finished worksheet! If you do not finish it in class you must finish it as homework and submit the finished worksheet at the beginning of class tomorrow.

30. Vapor Pressure Table H – the vapor pressure of four liquids at various temperatures.

31. Regents Question: 06/03 #40 According to Reference Table H, what is the vapor pressure of propanone at 45°C? (1) 22 kPa (2) 33 kPa (3) 70. kPa (4) 98 kPa

32. Boiling Point A liquid will boil when its vapor pressure equals the atmospheric pressure. Raising the temperature will increase the vapor pressure of the liquid Lowering the atmospheric pressure will lower the boiling point On top of a high mountain, water boils at a temperature below 100?C

33. Normal Boiling Point Standard (normal) pressure is 101.3 kilopascals (kPa) or 1 atmoshpere (atm) The normal boiling point occurs when the atmospheric pressure is 101.3 kPa (standard pressure) The normal boiling point of ethanol is 80ºC.

34. Regents Question: 08/02 #28 As the pressure on the surface of a liquid decreases, the temperature at which the liquid will boil (1) decreases (2) increases (3) remains the same

35. Regents Question: 08/02 #30 As the temperature of a liquid increases, its vapor pressure (1) decreases (2) increases (3) remains the same

36. Regents Question: 08/02 #44 The vapor pressure of a liquid is 0.92 atm at 60°C. The normal boiling point of the liquid could be (1) 35°C (3) 55°C (2) 45°C (4) 65°C The normal boiling point is the temperature at which a liquid boils when the atmospheric pressure is standard pressure (1 atm or 101.3 kPa)

37. Regents Question: 01/03 #68 What is the vapor pressure of liquid A at 70°C? Your answer must include correct units. 700 mm Hg

38. Regents Question: 01/03 #69 At what temperature does liquid B have the same vapor pressure as liquid A at 70°C? Your answer must include correct units. 113°C

39. Regents Question: 01/03 #70 Which liquid will evaporate more rapidly? Explain your answer in terms of intermolecular forces. Liquid A will evaporate more rapidly because, at any temperature, it has the weaker intermolecular forces.

40. Vapor Pressure Worksheet Directions: Complete the worksheets to the best of your ability. Turn in finished worksheet! If you do not finish it in class you must finish it as homework and submit the finished worksheet at the beginning of class tomorrow.

41. Vapor Pressure and Evaporative Cooling Lab #8