Chem 101 Book Answers (Ch.11)

Chem 101 Book - Chapter 11 Electrochemistry Electron Transfer 1 Define the oxidation and reduction processes Oxidation is the loss of electrons and

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 11 Electrochemistry & Electron Transfer 11-1 1. Define the oxidation and reduction processes. Oxidation is the loss of electrons and reduction is the gain of electrons. Oxidation results in an increase in an atom’s oxidation state and reduction results in a lowering (reduction) of the oxidation state. 3. Distinguish between donor and acceptor orbitals. Which orbital is on the oxidizing agent? Transferred electrons move from the donor to the acceptor orbital in a redox reaction. The donor orbital is on the reducing agent and the acceptor orbital is on the oxidizing agent. 5. What change in potential does an electron experience when it moves from a potential of +0.5 V to one at -0.3 V? Is this a spontaneous process? Change in potential = final potential – initial potential = -0.3 – 0.5 = -0.8 V. An electron’s free energy is greater at the more positive potential, so moving from high potential to low potential is moving from low free energy to high. Δ G > 0, so the process is not spontaneous. 7. The A/A 1+ couple is 0.5 V above the B/B 2+ couple. Which of the four species is the best oxidizing agent? Which is the best reducing agent. Write the balanced chemical equation for the spontaneous process that occurs when the two couples are connected in a galvanic cell. The A/A 1+ couple is at the higher potential, so it is at lower free energy. The direction of spontaneous electron flow is “downhill” in free energy, i.e., A B 2+ . Consequently, A is the best reducing agent and B is the best oxidizing agent. The spontaneous reaction occurring when the couples are connected is 2A + B 2A + B. 9. The energy level diagrams for elements V and W are shown in the text. Assume that the redox orbital energies are the dominant term in Δ G. a) Write the standard reduction half-reactions for V, W, V 2+ and W 2+ and order them from most negative at top to most positive at the bottom. W + 2e 1- U W 2- highest energy redox orbital V + 2e U V V + 2e U V W + 2e U W lowest energy redox orbital b) Of the species, V 2+ , W 2+ , V, W, V 2- , W 2- , which is the best oxidizing agent? Which is the best reducing agent? The best oxidizing agent is W 2+ , lowest unfilled orbital. The best reducing agent is W 2- , highest occupied orbital. c) Indicate whether each of the following electron transfer reactions would be extensive: i) V + W 2+ U V 2+ + W Yes, electron transfer is to lower energy. ii) V 2- + W U V + W 2- No, electron transfer is to higher energy.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/30/2009 for the course CH Ch101 taught by Professor Bigham during the Fall '08 term at N.C. State.

Page1 / 4

Chem 101 Book - Chapter 11 Electrochemistry Electron Transfer 1 Define the oxidation and reduction processes Oxidation is the loss of electrons and

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online