AP CHEMISTRY FINAL QUESTIONS

AP CHEMISTRY FINAL QUESTIONS

• Which of the following properties generally decreases across the periodic table from sodium to chlorine?(A) First ionization energy (B) Atomic mass (C) Electronegativity (D) Maximum value of oxidation number

(E) Atomic radius: 44. E

• What is the mole fraction of ethanol, C2H5OH, in an aqueous solution that is 46 percent ethanol by mass? (The molar mass of C2H5OH is 46 g; the molar mass of H2O is 18 g.)

(A) 0.25 (B) 0.46 (C) 0.54 (D) 0.67 (E) 0.75: 45. A

• The effective nuclear charge experienced by the outermost electron of Na is different than the effective nuclear charge experienced by the outer¬- most electron of Ne. This difference best accounts for which of the following?(A) Na has a greater density at standard conditions than Ne.(B) Na has a lower first ionization energy than Ne.(C) Na has a higher melting point than Ne.(D) Na has a higher neutron-to-proton ratio than Ne.

(E) Na has fewer naturally occurring isotopes than Ne.: 46. B

• Which of the following is a correct statement about reaction order?(A) Reaction order can only be a whole number.(B) Reaction order can be determined only from the coefficients of the balanced equation for the reaction.(C) Reaction order can be determined only by experiment.(D) Reaction order increases with increasing temperature.(E) A second-order reaction must involve at least two different compounds as reactants.: 47. C

• Sodium chloride is LEAST soluble in which of the following liquids?

(A) H2O (B) CCl4 (C) HF (D) CH3OH (E) CH3COOH: 48. B

• ... Cr2O72-(aq) + .. . H2S(g) + ... H+(aq) ’ ... Cr3+(aq) + ... S(s) + ... H2O(l)
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• When the equation above is correctly balanced and all coefficients are reduced to lowest whole-number terms, the coefficient for H+(aq) is

(A) 2 (B) 4 (C) 6 (D) 8 (E) 14: 49. D

• Which of the following represents acceptable lab¬oratory practice?(A) Placing a hot object on a balance pan (B) Using distilled water for the final rinse of a buret before filling it with standardized solu¬tion (C) Adding a weighed quantity of solid acid to a titration flask wet with distilled water (D) Using 10 mL of standard strength phenolph¬thalein indicator solution for titration of 25 mL of acid solution (E) Diluting a solution in a volumetric flask to its final concentration with hot water: 50. C

• 3 Cu(s) + 8 H+(aq) + 2 NO3-(aq) ’ 3 Cu2+(aq) + 2 NO(g) + 4 H2O(l)

• True statements about the reaction represented above include which of the following?

• Cu(s) acts as an oxidizing agent.

II. The oxidation state of nitrogen changes from +5 to +2.III. Hydrogen ions are oxidized to form H2O(l).

(A) I only (B) II only (C) III only (D) I and II (E) II and III: 51. B

• Propane gas, C3H8, burns in excess oxygen gas. When the equation for this reaction is correctly balanced and all coefficients are reduced to their lowest whole-number terms, the coefficient for O2 is

(A) 4 (B) 5 (C) 7 (D) 10 (E) 22: 52. B

• According to the VSEPR model, the progressive decrease in the bond angles in the series of molecules CH4, NH3, and H2O is best accounted for by the (A) increasing strength of the bonds (B) decreasing size of the central atom (C) increasing electronegativity of the central atom

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