AP Chemistry Final Exam. Multiple Choice. Note that when a series of questions is based on a set of choices, choices may be used more than once or not at all. Also note that a deduction of 1/4 point is made for wrong answers. The exam is scored: Number correct, – number incorrect
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Questions 1-3 refer to the following choices:
A) H2O B) NH3 C) BH3 D) CH4 E) SiH4
1. Has a central atom with less than an octet of electrons.
2. Has a trigonal-pyramidal molecular geometry
3. Is predicted to have the largest bond angle
Questions 4-6 refer to the following elements.
A) K B) Ca C) As D) Se E) Br
4. Can form a +1 ion that has an electron configuration [Ar]4s1
5. Has the largest atomic radius
6. Has atoms that have the highest first ionization energy
Questions 7 - 9 refer to the following descriptions of different types of bonding and structure in pure substances.
A) Ionic Bonding B) Covalent network
C) Strong single covalent bonds with weak forces between molecules
D) Strong multiple covalent bonds (including π- bonds)with weak forces between molecules
E) Closely packed lattice with mobile electrons
7. Type of bonding in compounds formed from two elements that have a large difference in electronegativity
8. Type of bonding in Cl2(l)
9. Type of bonding in Al(s)
Questions 10 - 13 refer to the following compounds.
A) CH3CH2CH2CH3 B) CH3CH2CH2OH
C) CH3COCH3 D) CH3COOH
E) CH3CH2CH2NH2
10. Has the lowest normal boiling point
11. Dissolves in water to form an acidic solution
12. Is the LEAST soluble in water
13. Is isomeric with CH3CH2CHO
14. Differences in which of the following properties make possible the separation of two liquids by the method of distillation?
A) pH B) vapor pressure C) freezing point
D) Electrical conductivity E) absorption of visible light.
15. All of the following statements regarding the liquid and solid phases of a pure substance are true except:
A) each phase has a vapor pressure
B) the solid phase exhibits a higher state of disorder (entropy)
C) At constant pressure, heat must be supplied to the solid phase to change it to the liquid phase
D) the transition temperature between the phases is strongly affected by pressure
E) At a given pressure, addition of impurities usually changes the melting temperature of the substance
16. What is the oxidation number of Tc in the complex ion [Tc2Cl8]3– ?
A) –3 B) +2 C) + 2.5 D) +3 E) + 3.5
17. The Kb of NH3 is 1.8 x 10–5 . The pH of a 0.50M aqueous solution of NH3 is closest to
A) 13.5 B) 11.5 C) 7.5 D) 3.5 E) 2.5
Questions 18-19 refer to the reactions listed below.
A) Rb2CO3(s) + 2 HSO4— (aq) à 2 Rb+(aq) + CO2(g) + 2 SO42–(aq) + H2O(ℓ)
B) Cl2(g) + H2O(l) à HOCl (aq) + Cl–(aq) + H+(aq)
C) 2 Al(s) + Mn2O3(s) à 2 Mn(s) + Al2O3(s)
D) 3 Mg(s) + N2(g) à Mg3N2(s)
E) Fe3+(aq) + 3 OH–(aq) à Fe(OH)3(s)
18. A precipitation reaction
19. A reaction in which a single species is both oxidized and reduced.
Questions 20 - 21 refer to the possible effects of changing the conditions of the system at equilibrium at 298 K.
2 PbS(s) + 3 O2 (g) à 2 SO2(g) + 2 PbO(s) DH°298 = –842 kJ
A) increase in the value of Kp B) Increase in the amount of O2 present at equilibrium
C) Increase in the amount of PbO(s) present at equilibrium D) Increase in the value of DH°298
E) No change in the equilibrium concentrations
20. Adding SO2(g) to the system.
21. Adding a catalyst for the reaction
2 NO(g) + 2 H2(g) à N2(g) + 2 H2O(g)
22. The following data have been obtained at 1200 K for the reaction represented by the equation above.
Initial H2 Conc, (M x 103) / Initial NO conc. (M x 103) / Initial Rate of Reaction(M s–1 x 107)
5.84 / 4.40 / 14.6
5.84 / 2.20 / 3.65
2.92 / 4.40 / 7.30
What is the rate law for this reaction?
A) Rate = k[H2][NO] B) Rate = k[H2]2[NO]2 C) Rate = k[H2]2[NO]
D) Rate = k[H2][NO]2 E) Rate = k [H2][NO]2
[N2][H2O]2
...CH3COCH3(g) + ... O2(g) ...CO2(g) + ...H2O
23. When the equation above is balanced and all coefficients are reduced to lowest whole number terms, the coefficient for O2(g) is A) 2 B) 4 C) 6 D) 8 E) 9
24. When a strong acid is titrated with a strong base using phenolphthalein as an indicator, the color changes abruptly at the endpoint of the titration and can be switched back and forth by the addition of only one drop of acid or base. The reason for the abruptness of this color change is that
A) A large change in pH occurs near the endpoint of this titration
B) a bufer solution exists at the endpoint of this titration
C) phenolphthalein is a strong proton donor D) the pH of water is very resistant to change
E) phenolphthalein is much more sensitive to the pH of a solution than most other indicators
25. A graph of the pressure of N2(g) at constant high temperature vs. PV/nRT is constructed. For relatively low pressures, the value of PV/nRT is approximately 1. At higher pressures, the value of PV/nRT becomes less than one, and then at still higher pressures, PV/nRT for the gas becomes greater than 1. The best explanation of this data is that
A) N2 becomes more ideal as the pressure increases
B) Deviations from ideal behavior due to attractions predominate at lower pressures, while deviations due to particle size predominate at higher pressures.
C) The attractions between the non-polar nitrogen molecules are not observable at the temperature used in the graph
D) Nitrogen molecules take up no significant portion of the gas volume at any point on the graph E) Positive deviations from ideality are produced as the gas molecules begin to liquify
26. Which of the following must be true about a chemical reaction at 25°C for which the standard enthalpy change, DH°, has a value of –50 kJ?
I. The enthalpy of the products is less than the enthalpy of the reactants.
II. The reaction is exothermic.
III. The reaction occurs spontaneously at 25°C
A) I only B) II only C) I and II D) I and III E) II and III
27. Which of the following is the electron configuration of an excited atom that is likely to emit a quantum of energy? A) 1s22s22p63s23p1 B) 1s22s22p63s23p5 C) 1s22s22p63s2
D) 1s22s22p63s1 E)1s22s22p63s13p1
28. Which of the following is a correct name for the compound represented below:
A) 2-methyl-4-ethylheptane B) 2,4-dimethylheptane C) 2,4-dimethylhexane
D) 2-methyl-4-ethylbutane E) 2,4-dimethyloctane
29. What is the molality of a solution of H3PO4 that contains 24.5 grams of phosphoric acid (molar mass = 98) in 100 grams of H2O ? A) 0.245 m B) 2.50 m C) 4.00 m D) 25.0 m E) 40.0 m
30.
31. Solid Al(NO3)3 is added to distilled water to produce a solution in which the concentration of nitrate, [NO3–] is 0.10 M. What is the concentration of aluminum ion, [Al3+] in this solution?
A) 0.010 M B) 0.033 M C) 0.066 M D) 0.10 M E) 0.30 M
32. When a sample of an ideal gas in a sealed rigid container is heated from 25̊C to 100̊C, all of the following quantities change except the A) pressure of the gas B) density of the gas C) total kinetic energy of the gas sample D) average speed of the gas molecules E) number of collisions per second of the gas molecules
33. A 0.500 gram sample of a monoprotic acid is dissolved in water and 40.0 mL of 0.100 M NaOH is needed to titrate the sample to the equivalence point. What is the molar mass of the acid? A) 50.0 g/mol B) 62.5 g mol–1 C) 125 g mol–1 D) 250 g mol–1
E) It cannot be determined from the information given
34, Which of the following substances is a strong electrolyte when dissolved in water?
A) sucrose B) ethanol C) sodium nitrate D) acetic acid E) ammonia
35. To determine the percentage of water in a hydrated salt, a student heated a 1.2346 g sample of the salt for 30 minutes; when cooled to room temperature, the sample weighed 1.1857 g. After the sample was heated for an additional 10 minutes and again cooled to room temperature, the sample weighed 1.1632 g. Which of the following should the student do next?
A) Use the smallest mass value to calculate the % water in the hydrated salt
B) Repeat the experiment with a new sample of the same mass and average the results
C) Reheat the sample until its mass is constant
D) Use the average of the mass values obtained after the two heatings to calculate the percentage of water in the hydrated salt
E) Transfer to AP bio
36. A student mixes 160. mL of 0.25 M HCl with 200. mL of 0.50 M HCl and then adds enough distilled water to the mixture to bring the final volume to 500. mL. What is the molarity of the HCl in the final solution?
A) 0.14 M B) 0.28 M C) 0.38 M D) 0.56 M E) 0.75 M
37. Resonance structures are not used to represent the bonding in which of the following species? A) SO2 B) C2H2 C) CH3COO– D) C6H6 E) CO32–
Metal X Metal Y Metal Z
0.050 mole 0.033 mole 0.025 mole
38. The molten chloride salts of three metals, X, Y, and Z are each electrolyzed using the same current for the same amount of time. The number of moles of each metal obtained is given in the table above. If the charge of metal X ion is known to be +2, what are the charges of metal Y ion and metal Z ion, respectively?
A) +3, +4 B) +3, +2 C) +3, +1 D) +2, +3 E) +1, +4
39. The phase diagram for a pure substance is shown above. The solid and gaseous phases of the substances can exist in equilibrium at conditions corresponding to which of the following?
A) Point I only B) Point III only C) Any point on the curve from I to II. D) Any point on the curve from II to III E) any point on the curve from II to IV
40. 2 KClO3(s) ª 2 KCl(s) + 3 O2(g)
What is the percentage yield of O2(g) if 12.3 g of KClO3 (molar mass 123) is decomposed to produce 3.2 g of O2 (molar mass 32) according to the equation above?
A) 100 % B) 67 % C) 50 % D) 33 % E) 10 %
Al3+(aq) + 3 e– ª Al(s) E° = –1.66 V
Ag+(aq) + e– ª Ag(s) E° = + 0.80 V
41. According to the standard reduction potentials given above, what is the standard cell potential for the reaction represented below?
3 Ag+(aq) + Al(s) ª 3 Ag(s) + Al3+(aq)
A) –1.74 V B) –0.86 V C) +1.74 V D) + 2.46 V E) + 4.06 V
...Ag(s) + ...H+ + ... NO3– ª ...Ag+(aq) + ... NO(g) + ...H2O
42. When the equation for the reaction above is balanced and all coefficients are reduced to lowest whole number terms, what is the coefficient for Ag(s) ? A) 1 B) 2 C) 3 D) 4 E) 5
43. A 66.0 sample of solid CO2 (molar mass 44 g) vaporizes completely to fill an empty plastic bag to a final volume of 22.4 liters at 0o C. What is the final pressure in the sealed bag?
A) 380 mm Hg B) 507 mm Hg C) 760 mm Hg D) 1140 mm Hg E) 1520 mm Hg
C2H5NH2(g) ª C2H4(g) + NH3(g)
44. The reaction represented above is first order with respect to ethylamine, C2H5NH2. At 500̊C the following results relating to the reaction rate were obtained.
Time (seconds) 0 200 400 600 800Partial pressure of 100 70.1 50.0 35.1 ?
C2H5NH2(mm Hg)
What is the partial pressure of C2H5NH2 at 800 seconds?
A) 0.0 mm Hg B) 12.5 mm Hg C) 17.5 mm Hg D) 21.0 mm Hg E) 25.0 mm Hg
Step 1: NO(g) + O3(g) ª NO2(g) + O2(g)
Step 2: NO2(g) + O(g) ª NO(g) + O2(g)
45. One reaction mechanism for the destruction of ozone, O3(g), is represented above. In the overall reaction, NO(g) is best described as A) an inhibiter B) a catalyst C) a reactant D) an intermediate E) a product
46. The number of moles of AgCl formed when 50.0 mL of 0.20 M AgNO3 and 25.0 mL of 0.10 M BaCl2 are mixed is closest to
A) 0.0010 mol B) 0.0025 mol C) 0.0050 mol D) 0.010 mol E) 0.015 mol
H2PO4–(aq) + HC2O4– ª HPO42–(aq) + H2C2O4 (aq)
47. If K < 1 for the reaction represented above, which of the following is the strongest base?
A) H2O B) H2PO4–(aq) C) HPO42–(aq) D) H2C2O4(aq) E) HC2O4–(aq)
48. What is the ratio of the rate of effusion of H2 gas to the rate of effusion of O2 gas if both are at 800 K? A) 32:1 B) 16:1 C) 8 :1 D) 4:1 E) 1:1
49. A compound with the molecular formula XF3 contains 50 percent F by mass. According to these data, the atomic mass of X is A) 19.0 amu B) 28.5 amu C) 50.0 amu D) 57.0 amu E) 114 amu
50.When solutions of aluminum nitrate, Al(NO3)3 and potassium chromate, K2CrO4, are mixed, a precipitate is observed to form. Which of the following correctly represents the net ionic equation for the reaction?
A) K+(aq) + NO3–(aq) ª KNO3(s)
B) Cr3+(aq) + 3 NO3–(aq) ª Cr(NO3)3(s)
C) Al3+(aq) + 3 NO3–(aq) + 2 K+(aq) + CrO42--(aq) ª AlCrO4(s) + K2(NO3)3 (s)
D) Al2+(aq) + CrO42--(aq) ª AlCrO4(s)
E) 2 Al3+(aq) + 3 CrO42–(aq) ª Al2(CrO4)3 (s)
51. A reaction produces a colorless gas, which is collected by water displacement. A glowing splint inserted into a bottle full of the gas is extinguished. The gas could be
A) N2 B) NO2 C) O2 D) Br2 E) Cl2
XY ª X+(aq) + Y–(aq)
52. The salt XY dissolves slightly in water according to the equation above. If at 25°C the solubility of XY is 1.0 x 10–8 moles per liter of solution, what is the value of Ksp, the solubility-product constant for XY at 25°C?
A) 1.0 x 10–4 B) 2.0 x 10–4 C) 1.0 x 10–8 D) 2.0 x 10–8 E) 1.0 x 10–16
CH3CH2COO– + HCN ª CH3CH2COOH + CN–
53. Which of the following act as Brønsted-Lowry bases in the reaction represented above?
A) CH3CH2COO– and CH3CH2COOH B) CH3CH2COO– and CN–
C) CH3CH2COO– and HCN D) CH3CH2COOH and CN–
E) CH3CH2COOH and HCN
54. The nonvolatile compound ethylene glycol, C2H6O2, forms nearly ideal solutions with water. What is the vapor pressure of a solution made from 1.00 mole of C2H6O2 and 9.00 moles of H2O if the vapor pressure of pure water at the same temperature is 25.0 mm Hg?