2018 AP Chemistry Scoring Guidelines © 2018 The College Board. College Board, Advanced Placement Program, AP, AP Central, and the acorn logo are registered trademarks of the College Board. Visit the College Board on the Web: www.collegeboard.org. AP Central is the official online home for the AP Program: apcentral.collegeboard.org AP® CHEMISTRY 2018 SCORING GUIDELINES Question 1 DH rxn © 2018 The College Board. Visit the College Board on the Web: www.collegeboard.org. AP® CHEMISTRY 2018 SCORING GUIDELINES Question 1 (continued) ‒ DH rxn © 2018 The College Board. Visit the College Board on the Web: www.collegeboard.org. AP® CHEMISTRY 2018 SCORING GUIDELINES Question 1 (continued) DH rxn DH rxn mol DH rxn By doubling the volumes, the number of moles of the reactants are doubled, which doubles the amount of energy produced. OR mcΔT 2 mcΔT . D n 2n Thus the magnitude is the same as calculated in the first experiment In the second experiment, D © 2018 The College Board. Visit the College Board on the Web: www.collegeboard.org. AP® CHEMISTRY 2018 SCORING GUIDELINES Question 2 ( ) DH 298 DS298 DG298 © 2018 The College Board. Visit the College Board on the Web: www.collegeboard.org. AP® CHEMISTRY 2018 SCORING GUIDELINES Question 2 (continued) K = e- DG / RT - 870 J/mol (8.314 J mol -1 K -1 )(298 K) K= e K = 0.70 PNO PNO 2 PN 2O 3 PN 2O 3 © 2018 The College Board. Visit the College Board on the Web: www.collegeboard.org. AP® CHEMISTRY 2018 SCORING GUIDELINES Question 2 (continued) 1 point is earned for a valid diagram. 1 point is earned for the correct answer. © 2018 The College Board. Visit the College Board on the Web: www.collegeboard.org. AP® CHEMISTRY 2018 SCORING GUIDELINES Question 2 (continued) 0.100 mol KOH 1000 mL KOH 0.0020 mol HNO2 0.100 L © 2018 The College Board. Visit the College Board on the Web: www.collegeboard.org. AP® CHEMISTRY 2018 SCORING GUIDELINES Question 3 1 point is earned for a correct electron configuration. . Fµ q1 q2 r2 . 1 point is earned for the correct half-reaction. © 2018 The College Board. Visit the College Board on the Web: www.collegeboard.org. AP® CHEMISTRY 2018 SCORING GUIDELINES Question 3 (continued) 17 48 ´ 0 0350 1000 0.000612 mol KMnO4 ´ = 0 000612 4 5 mol Fe2 + = 0.003059 mol Fe2 + 1 mol KMnO4 1 point is earned for calculating the number of moles of KMnO . 1 point is earned for the correct concentration of . 2+ The volumetric flask is designed to contain only 25.00 mL precisely. © 2018 The College Board. Visit the College Board on the Web: www.collegeboard.org. 1 point is earned for a valid explanation. AP® CHEMISTRY 2018 SCORING GUIDELINES Question 3 (continued) 7.531 g Fe2 O3 ´ 1 mol Fe2 O3 = 0.04716 mol Fe2 O3 159.70 g Fe2 O3 0.04716 mol Fe2 O3 ´ 0.09431 mol Fe ´ 2 mol Fe = 0.09431 mol Fe 1 mol Fe2 O3 55.85 g Fe = 5.267 g Fe 1 mol 5.267 g Fe ´ 100 = 78.33% 6.724 g sample © 2018 The College Board. Visit the College Board on the Web: www.collegeboard.org. AP® CHEMISTRY 2018 SCORING GUIDELINES Question 4 -1 -1 © 2018 The College Board. Visit the College Board on the Web: www.collegeboard.org. AP® CHEMISTRY 2018 SCORING GUIDELINES Question 5 0 0350 = - = ( 0 00455) 2 0 0304 = 6 81 ´ 10-4 © 2018 The College Board. Visit the College Board on the Web: www.collegeboard.org. AP® CHEMISTRY 2018 SCORING GUIDELINES Question 5 (continued) 1 2 1 2 - 1 2 1 2 0 035 2 - 0 0175 0 00345 0 0175 2 0 0175 © 2018 The College Board. Visit the College Board on the Web: www.collegeboard.org. AP® CHEMISTRY 2018 SCORING GUIDELINES Question 6 Ecell Ecell Ered (cathode) - Ered (anode) Ered © 2018 The College Board. Visit the College Board on the Web: www.collegeboard.org. AP® CHEMISTRY 2018 SCORING GUIDELINES Question 6 (continued) D æ -ç è -ö æ ÷ø çè 96 485 ö -÷ ø (1 54 ) © 2018 The College Board. Visit the College Board on the Web: www.collegeboard.org. AP® CHEMISTRY 2018 SCORING GUIDELINES Question 7 0 693 12 - 0 069 0 -1 © 2018 The College Board. Visit the College Board on the Web: www.collegeboard.org.
