CH 102 1st Edition Lecture 23Outline of Current Lecture I. Concentration CellII. Electrolytic CellsIII. Electrolysis of WaterIV. The Chlor-alkali CellV. ElectroplatingVI. Corrosion: Nondesirable Redox ReactionVII. RustingCurrent LectureI. Concentration Cella.b. When the cell concentrations are equal there is no difference in energy between the half-cells and no electrons flowc. The line above describes concentration celli. One half cell has a copper electrode dipped into a 0.020 M solution of copper sulfateii. The other half cell has a copper electrode dipped into a 3.0 M solution of copper sulfate d. Which half cell the anode and which is the cathodee. What is the value of the electrochemical (Ecell) potential for this concentration cell?II. Electrolytic CellsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.a. Use electrical power to drive a non-spontaneous electrical reactionb. Objective to obtain useful chemicalsc. Apply a potential (V) to the cell that reverses the non-spontaneous processd. Pass a current (A) through an electrolytee. Power (watts) = volts x amperes = V x Af. Charge (in coulombs) passed through the cell i. = current (A) x time (s) = Q (C)g. Electrons passed through the cell i. = charge (C) x 1 mole electrons/96,485 CIII. Electrolysis of Watera.IV. The Chlor-alkali Cella. Chlorine is produced at the anode by oxidation of chloride ionb. Hydrogen is produced at the cathode by reduction of protons in the electrolityec. Caustic (sodium hydroxide) solution remains behind in the electrolyteV. Electroplatinga. In electroplating, the work piece is the cathodei. Cations are reduced at cathode and plate to the surface of the work pieceii. The anode is made of the plate metal. The anode oxidizes and replaces the metal cations in the solution.b.VI. Corrosion: Nondesirable Redox Reactiona. In 1998 the NACE estimated the cost of corrosion to be 278 G$, which was 3.1% of GDP b. Corrosion is the spontaneous oxidation of a metal by chemicals in the environment.i. Mainly O2c. Because many materials used are active metals, corrosion can be a very big problem.d. Metals are often used for their strength and malleability, but these properties are lost when the metal corrodes.e. For many metals, the product of corrosion does not adhere to the metal, and as it flakes off more metal can corrode.VII. Rustinga. At the anodic regions, Fe(s) is oxidized to Fe2+.b. The electrons travel through the metal to a cathodic region where O2 is reduced. i. acidic solution from gases dissolved in the moisturec. The Fe2+ ions migrate through the moisture to the cathodic region, where they are further oxidized to Fe3+, which combines with the oxygen and water to form rust. i. Rust is hydrated iron(III) oxide, Fe2O3 · nH2O.1. The exact composition depends on the conditions.ii. Moisture must be present.1. Water is a reactant.2. It is required for ion flow between cathodic and anodic regions.d. Electrolytes promote rusting.i. They enhance current flow.e. Acids promote rusting.i. Lowering pH will lower E°red of
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