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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) ( 2 Rb+(aq) + CO2(g) + 2 SO42–(aq) + H2O(ℓ)

B) Cl2(g) + H2O(l) ( HOCl (aq) + Cl–(aq) + H+(aq)

C) 2 Al(s) + Mn2O3(s) ( 2 Mn(s) + Al2O3(s)

D) 3 Mg(s) + N2(g) ( Mg3N2(s)

E) Fe3+(aq) + 3 OH–(aq) ( 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) ( 2 SO2(g) + 2 PbO(s) (H(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 (H(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) ( 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, (H(, 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:

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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

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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) ( 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– ( Al(s) E( = –1.66 V

Ag+(aq) + e– ( 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) ( 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– ( ...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) ( 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) 0 200 400 600 800 |

|Partial 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) ( NO2(g) + O2(g)

Step 2: NO2(g) + O(g) ( 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– ( 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) ( KNO3(s)

B) Cr3+(aq) + 3 NO3–(aq) ( Cr(NO3)3(s)

C) Al3+(aq) + 3 NO3–(aq) + 2 K+(aq) + CrO42--(aq) ( AlCrO4(s) + K2(NO3)3 (s)

D) Al2+(aq) + CrO42--(aq) ( AlCrO4(s)

E) 2 Al3+(aq) + 3 CrO42–(aq) ( 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 ( 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 ( 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?

A) 2.50 mm Hg B) 7.50 mm Hg C) 12.5 mm Hg D) 22.5 mm Hg E) 27.5 mm Hg

S(s) + 3 F2(g) ( SF6(g)

55. When 0.50 mol of S(s) is mixed with 1.0 mol of F2(g) and a reaction occurs according to the equation above, what is the maximum mass of SF6 (molar mass 146 g) that can be formed? A) 24 g B) 49 g C) 54 g D) 73 g E) 146 g

56. Which of the following best accounts for the hazard of explosions at flour mills?

A) flour dust has a relatively high surface area B) Flour contains carbohydrates that have hydrogen bonds C) Flour contains a substance that has a high energy content and is unstable.

D) Flour processing produces acid vapors that react with the flour

E) Flour acts as a catalyst for the reaction between oxygen and atmospheric hydrogen

57. Which of the following describes the electron transfer when SnCl2 acts as a reducing agent?

A) Sn2+ loses electrons to form Sn4+ B) Sn2+ gains electrons to form Sn4+

C) Sn2+ gains electrons to form Sno D) Cl2– loses electrons to form Clo

E) Clo gains an electron to form Cl–

58. For element X, the first five ionization energies, I1 , I2 I3, I4, and I5 are as follows:

(in kJ per mole) I1 = 700 I2 = 1800 I3 = 8000 I4 = 10200 I5 = 13900

What is the most lilkely identity of element X ? A) Na B) Mg C) Si D) P E) S

59. Which of the molecules below contains carbon atoms with sp2 hybridization?

A) CH4 B) CH2Cl2 C) C2H6 D) C2H2Cl2 E) C2H4Cl2

60. For which of the reactions repreented below is the value of KP equal to the value of KC at the same temperature? A) CO(g) + H2O(g) ( CO2(g) + H2(g)

B) CO(g) + Cl2(g) ( COCl2(g)

C) CaCO3(s) ( CaO(s) + CO2(g)

D) 2 NOBr(g) ( 2 NO(g) + Br2(g)

E) N2O4(g) ( 2 NO2(g)

61. The change in boiling point caused by the addition of a nonvolatile solute to the solvent is best explained in terms of A) Le Chatelier’s Principle B) The change in temperature of the resulting solution C) the increased mass of the resulting solution D) the increased mole fraction of the solvent E) the decreased vapor pressure of the solvent

62. The structure of a molecule of “banana oil” is shown above. This organic compound is an example of A) an alcohol B) an amine C) a carboxylic acid D) an ester E) a ketone

63. Hydrogen bonding occurs in which of the following organic substances?

I. CH3OCH3 II. CH3CH2CH2CH2CH2CH3 III. CH3CH2OH

A) I only B) II only C) III only D) I and III only E) I, II and III

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64. Based on the equations above, the molar heat of sublimation of iodine, ( I2(s) ( I2(g) ) is calculated to be A) 15 kJ B) 21 kJ C) 31 kJ D) 42 kJ E) 62 kJ

65. Properties of a pure liquid that depend on the strength of the forces of attraction among the molecules of liquid include which of the following?

I. Normal boiling temperature II. Equilibrium vapor pressure III. Heat of vaporization

A) I only B) III only C) I and II only D) II and III only E) I, II, and III

66. A colored, water soluble solid decomposes when strongly heated, releasing a gaseous product. The solid could be A) CuSO4•5H2O B) CaCO3•6H2O C) KClO3

D) Al(OH)3 E) CoS

67. A student is given a clear, colorless aqueous solution of an unknown salt. The student tests the solution with pH paper and determines that the pH is between 9 and 11. Of the following salt solutions, which could be the student’s unknown?

I. KCl(aq) II. NH4NO3(aq) III. Na2CO3(aq)

A) I only B) II only C) III only D) I and II only E) I, II, and III

68. Which of the following is the most appropriate procedure for preparing 500.0 mL of 1.00 M HNO3(aq) from a more concentrated ( 10.0 M) HNO3(aq) solution?

A) Add 50.0 mL of the concentrated acid to 100 mL of water, cool to room temperature, then add 350 mL of water

B) Add 50.0 mL of the concentrated acid to 100 mL of water, cool to room temperature, then dilute to a volume of 500.0 mL with water

C)Add 50.0 mL of the concentrated acid to an empty Erlenmeyer flask, then dilute to a volume of 500 mL with water

D) Add 50.0 mL of the concentrated acid to 450 mL of water

E) Add 450 mL of water, in small portions, to 50.0 mL of the concentrated acid, cooling to room temperature after each addition

69. Solid NaOH is not suitable for use as a primary standard in determining the concentration of an unknown acid solution because NaOH

A) absorbs H2O on standing B) is too strong a base

C) is colorless D) reacts too quickly

E) reacts incompletely with acids

70. Isothermal expansion of an ideal gas produces a change in which of the following variables?

I. Density II. Entropy III. Pressure

A) III only B) I and II only C) I and III only D) II and III only E) I, II, and III

71. An unknown acid was titrated with a solution of NaOH. The pH was recorded as the titration proceeded, resulting in the titration curve shown above. The unknown acid could be which of the following? (titration curve is at top of page)

A) Acetic acid, CH3COOH B) Hydrochloric acid, HCl C) Formic acid, HCOOH

D) Nitric acid, HNO3 E) Oxalic acid, H2C2O4

Mg(s) + 2 HCl(aq) ( H2(g) + MgCl2(aq)

72. An experiment is performed in which the reaction represented above takes place in an open calorimeter. Which of the following does NOT need to be known to calculate the heat of reaction, (H rxn, per mole of magnesium? A) The mass of Mg used B) the atmospheric pressure in the laboratory C) The heat capacity of the calorimeter D) The heat capacity of the MgCl2(aq) solution E) The difference in temperature before and after the reaction.

Ni2+(aq) + 6 NH3(aq) ( [Ni(NH3)6}2+(aq)

73. The reaction represented above is best classified as

A) A Lewis acid-base reaction B) A Brønsted-Lowry acid-base reaction

C) An Arrhenius acid-base reaction D) an oxidation-reduction reaction

E) a precipitation reaction

74. When 3.00 L of 2.00 M Na2SO4 solution is mixed with 5.00 L of 2.00 BaCl2 solution, a white precipitate forms. The final concentration of Ba2+ solution is closest to

A) 0.250 M B) 0.500 M C) 0.750 M D) 1.25 M E) 1.50 M

75. Which of the following sublimes to produce a purple gas?

A) KMnO4(s) B) CO2(s) C) I2(s) D) Cu(s) E) C(s) (graphite

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