Name: ate: 1. Which statement correctly describes both gases and liquids?. Their shapes stay the same in any container.. Their shapes change when they are in different containers. 2. lex placed a small beaker of cold water on a hot plate and heated it for 10 minutes. He took the temperature of the water several times during those 10 minutes and recorded his data. lex claims that the graph below shows the relationship between temperature and time when water is heated.. Their volumes stay the same in any container.. Their volumes change when they are in different containers. Which statement best explains why the temperature leveled off in section 2 of the graph?. lex turned off the hot plate so the water did not get any warmer.. The water reached the boiling point, so the temperature no longer increased.. n experimental error caused the graph to level off, because the water temperature should keep increasing over time.. old water heats faster than warm water, so once the cold water was room temperature, it took more than 10 minutes to make it hot. page 1
3. Under the same conditions of pressure and temperature, a liquid differs from a gas because the molecules of the liquid. have no regular arrangement.. are in constant motion.. have stronger forces of attraction between them.. take the shape of the container they are in. 6. Which of the following statements best explains why ice floats on water?. Water has a higher specific heat than ice.. Ice has the same molecular mass as water.. Heat is absorbed when water changes from the solid state to the liquid state.. Hydrogen bonding causes water to be less dense in the solid state than in the liquid state. 4. If the attractive forces among solid particles are less than the attractive forces between the solid and a liquid, the solid will. probably form a new precipitate as its crystal lattice is broken and re-formed.. be unaffected because attractive forces within the crystal lattice are too strong for the dissolution to occur.. begin the process of melting to form a liquid.. dissolve as particles are pulled away from the crystal lattice by the liquid molecules. 7. Which of the following statements best explains why water vapor condenses as temperature decreases?. ollisions between water vapor molecules become elastic.. Water vapor molecules chemically react when they collide.. Water vapor molecules are pulled together by the force of gravity. 5. When water changes from solid to liquid to gas, which statement is true?. ttractive forces between water vapor molecules overcome molecular motion.. The mass (amount) stays the same.. The temperature goes down.. The temperature stays the same.. The mass (amount) is greater. page 2
8. Which of the following statements best describes what happens to water during evaporation?. The temperature of the water increases until the water molecules react with nitrogen in the air. 11. The graph shows the temperature changes as a sample of ice is heated. What is happening during time?. Water molecules on the surface overcome intermolecular forces and change into the gas phase.. Water molecules on the surface come in contact with air molecules and are pulled into the gas phase.. The temperature of the water increases until the water molecules separate and form oxygen and hydrogen gas.. The liquid is evaporating.. The liquid is feezing. 9. The average distance between molecules always increases during which of the following phase changes?. The solid is freezing.. The solid is melting.. gas to solid. liquid to gas. gas to liquid. liquid to solid 10. lthough H 2 O and H 2 S have similar molecular geometries, they exist as different states of matter at 20 and 1 atm. Which of the following statements best explains why H 2 O is a liquid and H 2 S is a gas under these conditions?. H 2 O is less dense than H 2 S.. H 2 O is less chemically reactive than H 2 S.. H 2 O has a smaller molecular mass than H 2 S.. H 2 O has stronger intermolecular forces than H 2 S. page 3
12. solid substance is heated at a uniform rate. This graph shows how the temperature of the substance changes as heat is added. 14. onsider this phase diagram: ccording to the energy diagram shown, the substance will boil at what temperature?. 60. 10. 90. 140 t what temperature does the normal boiling point occur?. 45. 60. 100. 110 13. This graph shows temperature vs. energy data for a substance. What is the melting point of this substance?. 0. 20. 50. 90 page 4
15. This is a heating curve for a substance. 16. onsider this phrase diagram. etween points X and Y, which would be observed?. Solid and liquid will be present.. Only vapor will be present.. Liquid and vapor will be present.. Only liquid will be present. What process is occurring when a substance changes from point X ( 130 and 50 kpa) to point Y (30 and 100 kpa)?. boiling. freezing. melting. sublimation page 5
17. This graph represents a heating curve of a substance. 18. This diagram represents a phase diagram for a substance. t which point do solid, liquid, and gas phases exist in equilibrium? Which region on the graph represents the solid phase?. 1. 2. 3. 4. I. II. III. IV page 6
19. This graph represents a phase diagram for a substance. 21. Use the information below to answer the following question. The following graph shows the change in temperature of a sample of H 2 O, which begins as ice, as thermal energy is added. Which region of the graph represents water H 2 O in the liquid form only? What is the state of the substance at point I?. 1. 2. 3. 4. gas. liquid. liquid and gas. solid and liquid 20. Which sequence represents matter that is losing energy?. solid gas liquid. solid liquid gas 22. Which of these forms of water has the greatest kinetic energy?. boiling water. melting water. freezing water. condensing water. gas solid liquid. gas liquid solid page 7
23. Which of the following models correctly represents the compound phosphorus trichloride (Pl 3 )? 24. Which of the following illustrations represents a pure substance?........ page 8
25. elow are four ball-and-stick models representing compounds. Which of these models best represents ammonia (NH 3 )? 26. The chemical formula for ammonia is NH 3. Which of the following is the correct Lewis electron dot structure for ammonia?........ 27. Limestone is a naturally occurring form of calcium carbonate. The correct formula for limestone is. a(o 3 ) 2.. ao 3.. a 2 O 3.. a 2 (O 3 ) 2. page 9
28. The diagram below represents particles of different elements in a crystal. 31. Which of the following statements best explains why atoms bond?. toms bond to make new substances.. toms bond to become less chemically stable. What type of bond holds these particles together?. covalent. hydrogen. toms bond to change from a liquid to a solid.. toms bond to become more chemically stable.. ionic. polar 29. What is the correct name for the compound with the chemical formula NH 4 NO 3?. ammonium nitrate. hydro-nitrogen oxide. ammonia mononitrite 32. The chemical structure of formaldehyde is shown below.. nitro-hydrogen nitrate What is the geometry around the carbon atom? 30. The Lewis dot structure of a compound is shown below.. bent. linear. tetrahedral. trigonal planar Which of the following elements does X represent in the structure?. carbon (). nitrogen (N). oxygen (O). fluorine (F) page 10
33. Two elements in a molecule have the same electronegativity values. Which of the following most likely holds the elements together and why?. an ionic bond, because electrons transfer from one element to the other. a nonpolar covalent bond, because the elements share electrons equally. a polar covalent bond, because the elements do not share electrons equally. an intermolecular force, because the elements do not form a chemical bond 35. In a hydrogen fluoride (HF) molecule, a hydrogen atom and a fluorine atom are held together by a polar covalent bond. Which of the following best explains why this bond is polar?. the large difference in the atomic radii of hydrogen and fluorine atoms. the large difference in the atomic masses of hydrogen and fluorine atoms. the large difference in the electronegativities of hydrogen and fluorine atoms. the large difference in the number of electrons of hydrogen and fluorine atoms 36. Which of the following are most directly involved in chemical bonding? 34. leaf gently floats on a pond. Which of the following statements best explains why the leaf stays on top of the water?. protons. neutrons. alpha particles. valence electrons. The leaf has nonpolar covalent bonds between its atoms.. The density of the leaf is greater than the density of the water.. The water molecules are held tightly together by hydrogen bonding.. The hydrogen and oxygen atoms in the water are chemically bonded. 37. Which of the following molecules has a nonpolar covalent bond?. H r. H l. H F. H H page 11
38. What is the name of the compound with the chemical formula (NH 4 ) 2 S? 40. Which of the compounds is formed by a covalent bond?. ammonium sulfide. hydrogen sulfate. sulfur hydride. sulfuric acid. Nal. al 2. Nar. 6 H 12 O 6 39. The diagram below shows three containers of gas. 41. The diagram shows a model of a methane molecule, which has the formula H 4. ontainer R ontainer S ontainer T Which list correctly describes the gases in containers R, S, and T?. R = element, S = compound, T = mixture. R = compound, S = element, T = mixture. R = element, S = mixture, T = compound. R = mixture, S = element, T = compound Which phrase correctly describes the relationship of the carbon and hydrogen atoms in a methane molecule?. They are held together by ionic bonds.. They share electrons to form covalent bonds.. They bond to each other since all nuclei are positively charged.. They are attracted to each other since the nucleus of each atom contains neutrons. page 12
42. What is the name of the compound PbO 2?. lead oxide. lead(ii) oxide. lead oxide(ii). lead(iv) oxide 46. What is the shape of a molecule which has two shared pairs of electrons and no unshared pairs?. tetrahedral. bent. trigonal planar. linear 43. Which is the correct formula for dinitrogen pentoxide?. N 4 O. NO 2. N 2 O 5. NO 4 47. substance dissolves well in water but not in benzene. Which of the following can be concluded about the substance?. The substance may be either polar or nonpolar.. The substance is nonpolar.. The substance is polar. 44. What type of bonding is associated with compounds that have the following characteristics: high melting points conduct electricity in the molten state solutions conduct electricity normally crystalline solids at room temperature.. covalent. ionic. hydrogen. metallic. The substance is neither polar nor nonpolar. 48. ased on the VSEPR theory, what is the molecular geometry of O 2?. linear. tetrahedral. trigonal planar. trigonal pyramidal 45. ased on the VSEPR theory, what is the molecular geometry of a molecule of PI 3?. linear. tetrahedral. trigonal planar. trigonal pyramidal 49. Which compound has the lowest normal boiling point?. Hl. H 2 S. NH 3. H 4 page 13
50. Why is NH 3 classified as a polar molecule?. NH 3 is a gas at STP.. N H bonds are nonpolar. 53. Which substance is made up of molecules that are dipoles?. N 2. H 2 O. H 4. O 2. Nitrogen and hydrogen are both nonmetals.. NH 3 molecules have asymmetrical charge distribution. 54. Which molecule is nonpolar due to a symmetrical distribution of charge? 51. Which molecule is nonpolar?. O====O. O. / H H. H l. O==O. N. / H H. O. / H H. H N H 2 H. H l 52. Which structural formula represents a nonpolar symmetrical molecule?. O. / H H. H 2 H H 2 H. H F. N.2/ H H H 55. In an experiment, a student determined the normal boiling points of four unknown liquids. The collected data were organized into the table shown. Unknown Normal Liquids oiling Points ( ) 10 33 78 100 Which unknown liquid has the weakest attractive forces between its molecules?.... page 14
56. Which formula represents a polar molecule?. Lir. Nar. Kr. Hr 59. When calcium chloride is dissolved in water, to which end of the adjacent water molecules will a calcium ion be attracted?. the oxygen end, which is the negative pole. the oxygen end, which is the positive pole. the hydrogen end, which is the negative pole. the hydrogen end, which is the positive pole 57. t 25, F 2 is a gas but I 2 is a solid. This is most likely due to the fact that. F 2 is a dipole but I 2 is not. I 2 is a dipole but F 2 is not. F 2 molecules have stronger intermolecular attractions. I 2 molecules have stronger intermolecular attractions 60. Which two compounds contain only polar molecules?. l 4 and H 4. Hl and l 2. Hl and NH 3. O and O 2 58. Which structural formula represents a polar molecule?. O. H / OH. O====O. H H. H 2 H H 2 H 61. Organic compounds that are essentially nonpolar and exhibit weak intermolecular forces have. low vapor pressure. low melting points. high boiling points. high electrical conductivity in solution page 15
62. The accompanying table shows the normal boiling point of four compounds. ompound Normal oiling Point ( ) Hf(l) 19.4 H 3 l(l) 24.2 H 3 F(l) 78.6 Hl(l) 83.7 Which compound has the strongest intermolecular forces? 65. Given the formula: The bond between which two atoms has the greatest degree of polarity?. and. and O. H and. H and O. HF(l). H 3 l(l). H 3 F(l). Hl(l) 66. Given the compound: 63. Hexane ( 6 H 14 ) and water do not form a solution. Which statement explains this phenomenon?. Hexane is polar and water is nonpolar.. Hexane is ionic and water is polar.. Hexane is nonpolar and water is polar.. Hexane is nonpolar and water is ionic. The symbol = represents. one pair of shared electrons. two pairs of shared electrons. a single covalent bond. a coordinate covalent bond 67. Given the structural formula: 64. Which of these substances has the strongest intermolecular forces?. H 2 O. H 2 S. H 2 Se. H 2 Te H H What is the total number of electrons shared in the bond between the two carbon atoms?. 6. 2. 3. 4 page 16
68. Given the formula of a substance: 70. The relatively high boiling point of water is primarily due to the presence of. hydrogen bonds What is the total number of shared electrons in a molecule of this substance?. 22. 11. 9. 6. van der Waals forces. molecule-ion attractions. ion-ion attractions 69. Given the formula for oxygen: 71. Hydrogen bonding is a type of. strong covalent bond What is the total number of electrons shared between the atoms represented in this formula?. 1. 2. 8. 4. weak ionic bond. strong intermolecular force. weak intermolecular force page 17
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