General Chemistry 1140 - A May 6, 2004 (6 Pages, 43 Parts) Name Each of the 40 multiple choice questions counts 2 point. Give the letter of the correct answer. 1. 2. Crystalline solids differ from amorphous solids in that: (A) All crystalline solid contain anions and cations. (B) All crystalline solids have a long range order while all amorphous solids do not. (C) All crystalline solids conduct electricity while all amorphous solids do not. (D) All crystalline solids are hard and strong while all amorphous solids are soft and brittle. (E) All of the above. (F) None of the above. Which of the following properties is a general characteristic of solids? (A) Solids have a rigid shape and fixed volume (B) Solids can have crystalline or noncrystalline structures (C) Solids do not compress or expand significantly (D) A substance is usually more dense as a solid than a liquid (E) All of the above 3. Which of the following is not an example of a molecular crystalline solid? (A) halite, NaCl (D) sucrose, C 12 H 22 11 (B) iodine, I 2 (E) urea, C (NH 2 ) 2 (C) phosphorus, P 4 4. 5. 6. 7. Which of the following explains why ice floats in water? (A) Molecules in ice are closer together. (B) The unit cell of ice has holes in it. (C) Ice has a smaller specific heat than water. (D) All of the above (E) None of the above Which of the following types of crystalline solids is hard and brittle, has a high melting point, and conducts electricity only when melted? (A) ionic (D) all of the above (B) molecular (C) metallic Which of the following types of crystalline solids is malleable, ductile, and a conductor of electricity? (A) ionic (D) all of the above (B) molecular (C) metallic Which of the following types of crystalline solids has a low melting point, is generally insoluble in water, and is a nonconductor of electricity? (A) ionic (D) all of the above (B) molecular (C) metallic
8. Consider the five pictures below. Each circle represents one carbon dioxide molecule. Which picture is the most realistic representation of solid C 2? (A) A (B) B (C) C (D) D (E) E A B C D E 9. Consider the five pictures above. Which is the most realistic representation of liquid H 2? (A) A (B) B (C) C (D) D (E) E 10. What is the term for the heat required to convert a solid to a liquid at its melting point? (A) heat of crystallization (D) specific heat (B) heat of fusion (C) heat of vaporization 11. Which of the following properties is a general characteristic of liquids? (A) liquids have a variable shape and fixed volume (B) liquids flow readily (C) liquids do not compress or expand significantly (D) a substance is much more dense as a liquid than a gas (F) None of the above 12. Which of the following properties is a general characteristic of liquids? (A) liquids have a fixed shape and variable volume (B) liquids compress and expand significantly (C) a substance is much less dense as a liquid than a gas (D) liquids that are soluble form heterogeneous mixtures 13. Water beads up on a freshly waxed automobile. This phenomenon is an example of: (A) Cohesive forces being weaker than adhesive forces. (B) Adhesive forces being stronger than cohesive forces. (C) Cohesive forces being stronger than adhesive forces. (D) Both a and b. 14. What is the term for the temperature at which the vapor pressure of a liquid is equal to the atmospheric pressure? (A) absolute zero (D) vapor point (B) boiling point (C) critical point 15. Which of the following explains why a needle can float on water? (A) The density of the water is greater than the needle. (B) The molar mass of the water is greater than the needle. (C) The surface tension of the water supports the needle. (D) The vapor pressure of the water supports the needle. (E) The viscosity of the water supports the needle.
16. Which statement is correct about the cooling curve at the right? (A) A is cooling of the solid (D) F is freezing of the liquid (B) B is freezing of the liquid (E) E is boiling of the liquid (C) After D, solid starts to form below the freezing point Temp. A B C D Time E F 17. List the three compounds below in order of increasing boiling point: A H B CH 3 C CH 3 (A) A, B, C (B) A, C, B (C) B, A, C (D) B, C, A (E) C, B, A 18. What is the common term for the pressure exerted by vapor molecules above a liquid in a closed container when the rates of evaporation and condensation are equal? (A) atmospheric pressure (D) vapor pressure (B) equilibrium pressure (C) gas pressure 19. If the molecules in a liquid have a strong attraction for each other, which of the following properties has a relatively low value? (A) boiling point (D) viscosity (B) surface tension (C) vapor pressure 20. What is the term for the tendency of a liquid to form spherical droplets? (A) dipole attraction (D) surface tension (B) dispersion forces (E) viscosity (C) intermolecular attraction 21. What is the strongest intermolecular force in dimethyl ether, CH 3 --CH 3? (A) ion-ion attraction (D) hydrogen bond (B) dipole-dipole attraction (E) metallic bond (C) dispersion force 22. What is the term for an attraction between two molecules with temporary dipoles? (A) covalent bond (D) hydrogen bond (B) dipole force (E) intermolecular bond (C) dispersion force 23. What is the term for an attraction between molecules that contain a hydrogen atom bonded to a highly electronegative atom such as oxygen or nitrogen? (A) dipole force (D) intermolecular bond (B) dispersion force (E) polar covalent bond (C) hydrogen bond 24. What is the strongest intermolecular force in a liquid having molecules with H- bonds? (A) covalent bonds (D) hydrogen bonds (B) dipole forces (C) dispersion forces
25. Which of the following is true of the intermolecular attraction in liquids? (A) Nonpolar molecules can be attracted by dispersion forces. (B) Polar molecules can be attracted by temporary dipole forces. (C) Polar molecules can be attracted by permanent dipole forces. (D) Polar molecules can be attracted by hydrogen bonds. 26. Which of the following properties of water would you predict to be unusually high? (A) melting point (D) heat of vaporization (B) boiling point (C) heat of fusion 27. What is the term that refers to two liquids that are soluble in one another in all proportions? (A) immiscible (D) Tyndall effect (B) equal vapor pressure (C) miscible 28. What is the term for the general principle that solubility is greatest when the polarity of the solute is similar to that of the solvent? (A) like dissolves like rule (D) solution principle (B) polarity principle (E) solvent principle (C) solute principle 29. What is the term for a solution that contains the maximum amount of solute that will dissolve at a given temperature at equilibrium? (A) colloid (D) solubility (B) concentrated (E) supersaturated (C) saturated 30. What is the term for a solution that contains more solute than is ordinarily soluble at a given temperature? (A) colloid (D) supersaturated (B) concentrated (E) unsaturated (C) saturated 31. Which of the following liquids is miscible with water. (A) chloroform, CHCl 3 (D) pentane, C 5 H 12 (B) cyclohexane, C 6 H 12 (E) toluene, C 6 H 5 CH 3 (C) glycerin, C 3 H 5 (H) 3 32. Sodium chloride, NaCl, dissolves in water because: (A) It takes very little energy to separate water molecules from water molecules. (B) It takes very little energy to separate sodium ions from chloride ions. (C) The solution has a more entropy than the separated sodium chloride and water. (D) All of the above. (E) None of the above. 33. Carbon tertrachloride, CCl 4, dissolves in hexane, C 6 H 14, because: (A) It takes very little energy to separate CCl 4 molecules from CCl 4 molecules. (B) It takes very little energy to separate C 6 H 14 molecules from C 6 H 14 molecules. (C) The solution has a more entropy than the separated CCl 4 and C 6 H 14. (D) All of the above. (E) None of the above.
34. A colligative property is one that: (A) Depends largely on the number of solute particles and not the nature of the solute particles. (B) Depends largely on the nature of the solute particles and not the number of solute particles. (C) Depends largely on both the number of solute particles and the nature of the solute particles. (D) Depends largely on factors other than the number of solute particles and the nature of the solute particles. 35. In osmosis: (A) Solute particles pass through a semipermeable membrane from low to high concentration of solute. (B) Solute particles pass through a semipermeable membrane from high to low concentration of solute. (C) Solvent particles pass through a semipermeable membrane from low to high concentration of solute. (D) Solvent particles pass through a semipermeable membrane from high to low concentration of solute. 36. If a bacterium is placed in solid salt, the bacterium will: (A) Explode due to rupturing the cell membrane. (B) Shrivel up like a raisin. (C) None of the above since salt cannot readily pass through the cell membrane. 37. If a bacterium is placed in pure water, the bacterium will: (A) Explode due to rupturing the cell membrane. (B) Shrivel up like a raisin. (C) None of the above since water cannot readily pass through the cell membrane. 38. For the solvent water, substances can be hydrophobic, hydrophilic, or duel-nature. Which substance is hydrophobic? (A) ethanol (B) gasoline (C) soap 39. Which of the following molecules would be a suitable surfactant? (A) only 1 1. (B) only 2 (C) only 3 (D) only 4 2. (E) 1 and 2 (F) 1 and 3 3. (G) 1 and 4 (H) 2 and 4 (I) all 4. 40. Dacron is a polyester with the structure at the right. The structure of the monomer containing the phenyl group (benzene ring) used to make this copolymer is: S 3 SH NH 3 [ ] A H H B C H H D H H E H H
41. (8%) Place the letter of the structure on the right in front of the compound on the left: An anhydride An ester Benzene Butanal 1-Butanol 2-Butanol Cyclohexane Decane 3-Decene Hexanal Hexanoic acid 2-Hexanone 3-Hexanone Hexyl amine ctane Pentane A D H K L H P M B I E NH 2 F H H N C H G J S Not Given Above H 42. (5%) Four separate solutions were prepared by dissolving exactly one mole of each of the following in exactly one kilogram of water. The melting points of each solution then was obtained. The melting points of these solutions and the melting point of pure water are listed on the left. The various samples are listed on the right. Answer the question by placing the letter of the sample on the right in front of the melting point of its solution on the left. The freezing point depression constant for water is 1.86 o /m or 1.86 o /c m. a. 0.00 o b. -1.86 o c. -1.95 o d. -3.72 o e. -5.58 o A. Ammonium hydroxide B. Calcium nitrate C. Ethanol D. Pure water E. Sodium chloride 43. (7%) A 3.40 g sample of an unknown compound was dissolved in 200.0 g of benzene. The melting point of the solution was 4.86 o. Determine the molar mass (molecular weight) of the unknown compound. Show work for credit! The melting point of pure benzene is 5.54 o. The freezing point depression constant for benzene is 5.12 o /m or 5.12 o /c m.