1. Choose the CORRECT abbreviated electron configuration for copper. a. [Ar] 4s 1 3d 10 b. [Ar] 4s 1 3d 8 c. [Ar] 4s 2 3d 9 d.

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1 AP Chemistry Fall Practice Semester Exam 3 Write the letter for the correct answer to the following questions on the provided answer sheet. The K f for water is 1.86 C kg/mol and the K b for water is 0.51 C kg/mol. 1. Choose the CORRECT abbreviated electron configuration for copper. a. [Ar] 4s 1 3d 10 b. [Ar] 4s 1 3d 8 c. [Ar] 4s 2 3d 9 d. [Ar] 4s 2 3d 7 2. Choose the CORRECT complete electron configuration for tin. a. 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 3 b. 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 2 c. 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 5d 10 4f 14 6p 2 d. 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 5d 4 4f From the following enthalpy changes, C (s) + O 2 (g) CO 2 (g) H 2 (g) + 1/2 O 2 (g) H 2 O (l) C 5 H 12 (g) + 8 O 2 (g) 5 CO 2 (g) + 6 H 2 O (l) calculate the value of ΔH for the reaction 5 C (s) + 6 H 2 (g) C 5 H 12 (g). ΔH f = kj ΔH f = kj ΔH = kj a kj b kj c kj d kj 4. Choose the smallest ion of the choices given. a. Ca +2 b. Cl -1 c. K +1 d. S Which of the following elements has the least electronegativity? a. N b. Ca c. Rb d. Al 6. Calculate the formal charge on the bromine in the hypobromite ion. a. 0 b. +1 c. +2 d Which of the following molecules doesn't have a dipole moment? a. NI 3 b. NeF 2 c. SF 4 d. BF 3 8. Which of the following atoms or ions has 3 unpaired electrons? a. N b. O c. Al d. S -2 e. Zn An element has the electron configuration [Ar]4s 2 3d 10 4p 2. The element is a(n) a. nonmetal b. transition element c. metal d. metalloid 10. All alkali metals have the following number of valence electrons. a. 1 b. 2 c. 7 d Which of these elements would have chemical properties most similar to element 116? a. S b. Uuo c. At d. Fr

2 12. Consider the following sets of quantum numbers. Which set(s) represent(s) possible combinations? n l m l m s set a ½ set b ½ set c ½ set d ½ set e set f ½ a. sets a & f b. sets a, d, & e c. sets c & f d. sets b, c, & f 13. How many electrons can be contained in all of the orbitals with n = 3, l = 1, ml = 0? a. 2 b. 8 c. 10 d Which of the following elements have the greatest ionization energy? a. Tc b. As c. Ba d. S 15. Select the correct molecular structure for SeF 6 a. square pyramidal d. triangular planar b. octahedral e. triangular bipyramidal c. square planar f. unsymmetrical tetrahedral 16. Determine the standard enthalpy of reaction for the combustion of hydrogen sulfide gas, which proceeds according to the reaction shown below: 2 H 2 S (g) + 3 O 2 (g) 2 H 2 O (l) + 2 SO 2 (g) The standard enthalpies for the constituents are as follows: Formula ΔH f (kj/mol) H 2 S (g) 20.0 H 2 O (l) SO 2 (g) a. 575 kj d kj b. 726 kj e kj c. 963 kj 17. A solution is made by dissolving 250. grams of potassium chromate crystals in 1.00 kg of water. What will the freezing point of the new solution be? a C d C b C e C c C f C

3 18. Which molecule has a Lewis structure that does not obey the octet rule? a. NO b. CS 2 c. PF 3 d. HCN e. CCl Which of the following molecules has a trigonal pyramidal shape? a. PCl 5 b. N 2 O c. NH 3 d. CCl 4 e. H 2 O Which of the following ions does not have a noble gas electron configuration? a. Sc +3 b. Al +3 c. O -2 d. N -3 e. Li What is the hybridization around the central atom in a molecule of silicon tetrachloride? a. sp 3 b. sp 2 c. sp d. dsp 3 e. d 2 sp Which of these explains that the C C bonds in benzene are all the same length? a. hydrogen bonding d. resonance b. hybridization e. London dispersion forces c. ionic bonding f. molecular orbitals 23. The vapor pressure of water at 50.0 C is 92.5 mm Hg. If 400. g of sucrose (C 12 H 22 O 11 ) is added to 900. g of H 2 O at 50.0 C, what is the vapor pressure (mm Hg) of the solution? a b c d e Which molecule listed below has two sigma and two pi bonds? a. N 2 b. C 2 H 4 c. N 2 F 2 d. C 2 H 2 Cl 2 e. HCN 25. For the following reaction A + B C + D ΔH = +40. kj and ΔS = +50. J/K. Therefore, the reaction under standard conditions is: a. spontaneous at temperatures less than 10 K. b. spontaneous at temperatures greater than 800 K. c. spontaneous only at temperatures between 10 K and 800 K. d. spontaneous at all temperatures. e. nonspontaneous at all temperatures. 26. Choose the answer that explains why the boiling point of helium is 269 C and the boiling point of xenon is 108 C. a. hydrogen bonding d. resonance b. hybridization e. London dispersion forces c. ionic bonding f. molecular orbitals 27. At normal atmospheric pressure and a temperature of 0 C, which phases(s) of H 2 O can exist? a. ice and water d. water vapor only b. ice and water vapor e. ice only c. water only

4 28. In the structural diagram of BHT, butylated hydroxytoluene how many sigma bonds are present? a. 3 b. 6 c. 16 d. 37 e. 38 f If a constant pressure of one atmosphere is maintained, how much energy is given off when 625 grams of water vapor at 118 C is cooled to ice at 11.8 C? (The specific heat of ice is 2.10 J/g C. The specific heat of liquid water is 4.18 J/g C. The specific heat of steam is 1.8 J/g C. The heat of vaporization is 43.9 kj/mol and the heat of fusion is 6.0 kj/mol.) a. 299 kj b. 328 kj c kj d. 31,500 kj 30. When solid sodium hydroxide is added to water at 25 C, it dissolves and the temperature of the solution increases. Which of the following is true for the values of ΔH and ΔS for the dissolving process? ΔH ΔS a. + + b. + c. 0 0 d. e If the temperature of a solution changes, which measure of concentration will change? a. mass percent d. molarity b. mole fraction e. none of these measures will change c. molality 32. Liquid A and liquid B form a solution that behaves ideally according to Raoult's law. The vapor pressure of the pure substances A and B are 75 mm Hg and 25 mm Hg, respectively. Determine the vapor pressure (mm Hg) over the solution if 1.50 moles of liquid A is added to 5.50 moles of liquid B. a b c d. 125 e Consider the reaction C 2 H 6 (g) C 2 H 4 (g) + H 2 (g) ΔH = 137 kj and ΔS = 120. J/K Based on the above data, the reaction will be: a. spontaneous at all temperatures. b. spontaneous at high temperatures. c. spontaneous only at low temperatures. d. nonspontaneous at all temperatures.

5 34. Consider the phase diagram to the right of a pure substance. The normal boiling point for the substance is: a. 58 C b. 68 C c. 70. C d. 90. C e C 35. Predict the bond order of molecular nitrogen. a. 0 b. 1 c. 2 d Predict the magnetism of molecular oxygen. a. paramagnetic b. diamagnetic c. non-magnetic 37. Which of the following is true at the triple point of a pure substance? a. The vapor pressure of the solid phase always equals the vapor pressure of the liquid phase. b. The temperature is always 0.01 K lower than the normal melting point. c. The liquid and gas phases of the substance always have the same density and are therefore indistinguishable. d. The solid phase always melts if the pressure increases at constant temperature. e. The liquid phase always vaporizes if the pressure increases at constant temperature. 38. The SbCl 5 molecule has a trigonal bipyramidal structure. Therefore, the hybridization of Sb orbitals should be: a. sp 3 b. sp 2 c. sp d. dsp 3 e. d 2 sp Which of the following must be true for a reaction that proceeds spontaneously from initial standard state conditions? a. ΔG > 0 and K eq > 1 b. ΔG > 0 and K eq < 1 c. ΔG < 0 and K eq > 1 d. ΔG < 0 and K eq < 1 e. ΔG = 0 and K eq = 1

6 40. Consider the diagram of BARF, tripentafluorophenylborane. What is the hybridization of the boron in BARF? a. sp b. sp 2 c. sp 3 d. dsp 3 e. d 2 sp Pi bonding occurs in each of the following species EXCEPT: a. CO 2 b. C 2 H 4 c. CN 1 d. C 6 H 6 e. CH 4 For questions 42-45, refer to the phase diagram of a pure substance. Select the one lettered choice that best fits each statement. A choice may be used once, more than once, or not at all in this set of questions. a. Freezing b. Melting c. Sublimation d. Condensation e. Vaporization 42. If the temperature increases from 40. C to 60. C at a pressure of 1.5 atm, which process is occurring? 43. If the temperature increases from 20. C to 60. C at a pressure of 0.5 atm, which process is occurring? 44. If the pressure increases from 0.5 atm to 1.0 atm at 60. C, which process is occurring? 45. What is the normality of a 0.25 M solution of phosphoric acid? a N d N b N e N c N

7 46. What is the molarity of a solution of 14.1 grams of zinc bromite dissolved in enough distilled water to form 748 ml of solution? a M b M c M d M 47. What is the molality of a solution of 8.44 grams of copper (II) thiocyanate dissolved in 324 g of distilled water? a m b m c m d m 48. A solution is prepared by adding 5.84 grams of formaldehyde, H 2 CO, to grams of water. The final volume of the solution was ml. Calculate the mole fraction of the formaldehyde in the solution. a b c d How many grams of glycerin (C 3 H 8 O 3 ) must be added to g in order to lower the freezing point to 3.84 C? a. 542 g b g c. 242 g d g 50. Which section has been the most difficult for you this semester? a. Chapter 7 d. Chapter 10 b. Chapter 8 e. Chapter 11 c. Chapter 9 f. Chapter 16