Ch.19 - Electrochemistry

McMurry8th EditionChemistryISBN: 9781292336145당신이 사용하는 게 아니라요?교과서 변경

McMurry 8th Edition

Ch.19 - Electrochemistry

문제 103

19장, 문제 103

At one time on Earth, iron was present mostly as iron(II). Later, once plants had produced a significant quantity of oxygen in the atmosphere, the iron became oxidized to iron(III). Show that Fe2+(aq) can be spontaneously oxidized to Fe3+(aq) by O2(g) at 25°C assuming the following reasonable environmental conditions:

검증된 단계별 안내

Identify the half-reactions involved in the oxidation of Fe^{2+} to Fe^{3+} and the reduction of O_2 to H_2O.

Write the oxidation half-reaction: Fe^{2+} \(\rightarrow\) Fe^{3+} + e^{-}.

Write the reduction half-reaction: O_2 + 4H^+ + 4e^{-} \(\rightarrow\) 2H_2O.

Determine the standard reduction potentials (E^\(\circ\)) for both half-reactions from a standard reduction potential table.

Calculate the standard cell potential (E^\(\circ\)_{cell}) using the formula: E^\(\circ\)_{cell} = E^\(\circ\)_{cathode} - E^\(\circ\)_{anode}. If E^\(\circ\)_{cell} is positive, the reaction is spontaneous.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.

영상 길이:

56s

도움이 되었나요?

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Oxidation and Reduction

Oxidation refers to the loss of electrons from a substance, while reduction is the gain of electrons. In the context of the question, Fe2+ is oxidized to Fe3+ as it loses an electron, and O2 acts as the oxidizing agent, facilitating this process. Understanding these concepts is crucial for analyzing redox reactions.

Standard Electrode Potentials

Standard electrode potentials (E°) provide a measure of the tendency of a chemical species to be reduced. The difference in E° values between the half-reactions of Fe2+/Fe3+ and O2/H2O can be used to determine the spontaneity of the reaction. A positive cell potential indicates that the reaction can occur spontaneously under standard conditions.

Gibbs Free Energy

Gibbs free energy (ΔG) is a thermodynamic potential that helps predict the spontaneity of a reaction. A negative ΔG indicates that a reaction can occur spontaneously. The relationship between ΔG, the standard electrode potential, and temperature is essential for determining whether the oxidation of Fe2+ by O2 is thermodynamically favorable.

관련 실천

교과서 질문

What is the pH of the solution in the cathode compartment of the following cell if the measured cell potential at 25 °C is 0.17 V?

837

views

교과서 질문

Copper reduces dilute nitric acid to nitric oxide (NO) but reduces concentrated nitric acid to nitrogen dioxide (NO2): Assuming that [Cu2+] = 0.10 M and that the partial pressures of NO and NO2 are 1.0 * 10-3 atm, calculate the potential (E) for reactions (1) and (2) at 25 °C and show which reaction has the greater thermodynamic tendency to occur when the concentration of HNO3 is (a) 1.0 M

863

views

교과서 질문

When suspected drunk drivers are tested with a Breathalyzer, the alcohol (ethanol) in the exhaled breath is oxidized to acetic acid with an acidic solution of potassium dichromate: The color of the solution changes because some of the orange Cr₂O₇^2-is converted to the green Cr³⁺ The Breathalyzer measures the color change and produces a meter reading calibrated in blood alcohol content. (a) What is E° for the reaction if the standard half-cell potential for the reduction of acetic acid to ethanol is 0.058 V?

801

views

교과서 질문

When suspected drunk drivers are tested with a Breathalyzer, the alcohol (ethanol) in the exhaled breath is oxidized to acetic acid with an acidic solution of potassium dichromate: The color of the solution changes because some of the orange Cr₂O₇^2-is converted to the green Cr³⁺ The Breathalyzer measures the color change and produces a meter reading calibrated in blood alcohol content. (b) What is the value of E for the reaction when the concentrations of ethanol, acetic acid, Cr₂O₇ are 1.0 M and the pH is 4.00?

975

views