General Chemistry A

Transcription

1 General Chemistry A May 5, 2005 (6 Pages, 48 Questions) ame 1. 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 2. What is the melting point of a 1.0 m aqueous Ba( 3 ) 2 solution if the freezing point depression constant for water is 1.86 o /m or 1.86 o /c m (A) 1.86 o (B) 0.00 o (C) o (D) o (E) o (F) o 3. What is the melting point of a 1.0 m aqueous F solution if the freezing point depression constant for water is 1.86 o /m or 1.86 o /c m (A) 1.86 o (B) 0.00 o (C) o (D) o (E) o (F) o 4. 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) one of the above 5. 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 6. 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 7. 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. Which of the following is the expected order of the boiling points of 2, e, F 2, and e? (A) 2 e F 2, e (B) 2 F 2, e e (C) e 2 e F 2 (D) e 2 F 2 e (E) e 2 e F 2

2 9. ylon rope, a polyamide fiber product, has a tendency to stretch when it becomes wet (such as in a rainstorm). The reason is: (A) The water leads to cooling of the rope. (B) The water molecules act like plasticizers. (C) The nylon polymer molecules degrade in the presence of water. (D) The water molecules disrupt the intermolecular hydrogen bonds. (E) one of the statements are correct 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 11. Consider the five pictures above. Which is the most realistic representation of liquid 2? (A) A (B) B (C) C (D) D (E) E 12. List the three compounds below in order of increasing boiling point: A B C a (A) A, B, C (B) A, C, B (C) B, A, C (D) B, C, A (E) C, B, A (F) C, A, B 13. 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 (E) all of the above (F) one of the above 14. What is the common term for the temperature at which the vapor pressure of a liquid is equal to the atmospheric pressure? (A) absolute zero (D) equilibrium point (B) boiling point (E) melting point (C) critical point (F) none of the above 15. The structure of a polymer is shown below. Which compound is the monomer which produced this polymer? A B Cl Cl [ ] n D C

3 16. 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. 17. 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. 18. 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 19. List the three compounds below in order of increasing boiling point: A B (A) A, B, C (C) B, A, C (E) C, A, B (B) A, C, B (D) B, C, A (F) C, B, A C 20. 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 (C) gas pressure (B) equilibrium pressure (D) vapor pressure 21. 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 (E) all of the above (C) vapor pressure 22. 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 23. What is the strongest intermolecular force in dimethyl ether, C 3 --C 3? (A) ion-ion attraction (D) hydrogen bond (B) dipole-dipole attraction (E) metallic bond (C) dispersion force 24. 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

4 25. 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 26. Which macromolecule would be made up of the type of molecule at the right? (A) carbohydrate (D) RA (B) DA (E) Teflon (C) protein (F) none of the above R The substance with the highest melting point is: (A) Ca (D) acl (B) Br (E) SF 6 (C) 2 (F) Xe 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. A capillary tube was placed in a liquid in a beaker and the liquid rose up the capillary. A and B show what the liquid might look like at the top of the capillary. The correct statement is: (A) Cohesive forces are stronger than adhesive forces and the top is A. (B) Cohesive forces are stronger than adhesive forces and the top is B. (C) Cohesive forces are weaker than adhesive forces and the top is A. (D) Cohesive forces are weaker than adhesive forces and the top is B. 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. Sodium chloride, acl, 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) one of the above. 32. Carbon tetrachloride, CCl 4, dissolves in hexane, C 6 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 14 molecules from C 6 14 molecules. (C) The solution has a more entropy than the separated CCl 4 and C (D) All of the above. (E) one of the above.

5 Use the structures below to answer Questions 33, 34, and 35. P A B C F G R D 2 E 33. Which statement is correct regarding melting points? (A) G melts at -11 o and melts at +70 o. (B) melts at -11 o and G melts at +70 o. (C) Since G and both have 18 carbon atoms and 2 oxygen atoms, their melting points should be the the same. 34. The compound or compounds which make up DA? (There may also be others which are not shown!) (A) A and B (D) B and C (G) F (B) A and C (E) D () F and G (C) A and F (F) E and G (I) none of the above 35. The compound or compounds which make up a fat? (There may also be others which are not shown!) (A) A and B (D) B and C (G) F (B) A and C (E) D () F and G (C) A and F (F) E and G (I) none of the above 36. 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. 37. 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. 38. 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) one of the above since salt cannot readily pass through the cell membrane. 39. 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) one of the above since water cannot readily pass through the cell membrane.

6 40. For the solvent water, substances can be hydrophobic, hydrophilic, or duel-nature. Which substance is hydrophobic? (A) ethanol (B) gasoline (C) soap 41. A portion of a nylon polymer is shown below. The monomer or monomers used to prepare this nylon are listed under the polymer. This nylon was prepared from: a nylon 2 A 2 B C 2 (A) A (C) A and C (E) B (G) C (B) A and B (D) A, B, and C (F) B and C () none of these 42. A g sample of an unknown compound was dissolved in g of benzene. The melting point of the solution was found to be 3.62 o. The freezing point of pure benzene is 5.54 o and the freezing point depression constant for benzene is 5.12 o /m or 5.12 o /c m. The molar mass of the unknown compound is: (A) 16 g/mole (C) 48 g/mole (E) 140 g/mole (G) 160 g/mole (B) 32 g/mole (D) 1.0 X 10 2 g/mole (F) 150 g/mole () ot given. Use the compounds below to answer Questions Be careful to give the letter of the ASWER and not the letter of the compound!!! A F B C 2 G I J D An alkane is: (A) A (B) B (C) D (D) E 44. A ketone is: (A) C (B) F (C) G (D) 45. An amine is: (A) E (B) (C) I (D) J 46. An ether is: (A) C (B) D (C) (D) J 47. An aldehyde is: (A) F (B) G (C) (D) I 48. An ester is: (A) D (B) (C) I (D) J E C 3