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Unformatted text preview: on that takes place at the cathode, and O2 + 4 H+ + 4 e− → 2 H2O One point is earned for either the equation of the correct half
reaction, or for indicating “the reduction half reaction” if the
correct equation is given in (b)(i) . (iii) determine the value of the standard potential, E°, of the cell. E° = 1.23V + 0.00 V = 1.23 V One point is earned for the standard potential. © 2007 The College Board. All rights reserved.
Visit apcentral.collegeboard.com (for AP professionals) and www.collegeboard.com/apstudents (for students and parents). AP® CHEMISTRY
2007 SCORING GUIDELINES (Form B)
Question 3 (continued)
(c) Calculate the charge, in coulombs, that passes through the cell during the 78.0 minutes of operation as
described in part (a). − (0.0746 mol O2 ) × 4 mol e
96, 500 C
= 2.88 × 104 C
1 mol O2
1 mol e− One point is earned for the
One point is earned for the
answer. © 2007 The College Board. All rights reserved.
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This note was uploaded on 10/01/2009 for the course OC 9876 taught by Professor Dq during the Spring '09 term at UC Merced.
- Spring '09