CHE 1302 Study Guide - Quiz Guide: Ph Meter, Standard Hydrogen Electrode, Nernst Equation

CHM 1045 Graves Chapter 4.6 Learning Objectives 4.10 Balance a simple redox equation using the half-reaction method Prep Assignments Reading Chapter 9.4 Iproblems 40-55] Balancing simple redox equations Things to remember Oxidation and reduction must happen together (a species must lose electrons and another species must gain them). . Number of electrons lost must be equal to number of electrons gained. The charges need to be balanced on both sides of the equation. Consider the following equation Cr (s) + Ni2+ (aq)→ Cr3+ (aq) + Ni (s) Is this equation balanced? How can you tell? To balance we need to separate the reaction into two half reactions What does the term oxidation mean? What does the term reduction mean? Write down the oxidation half reaction Write down the reduction half reaction What do you notice about the side electrons are in the oxidation and reduction half reactions you wrote? What do you notice about the numbers of the electrons in the oxidation and

1. Balancing electron transfer reactions. (Redox Tutorial; Krauskopf & Bird, Ch. 9, pg. 217- 235) + stoichiometrically balance the following overall reactions. For some, you may need to add H OH. Start by writing balanced half-potential reactions and then combining them into overall reactions. Make sure your final reactions are both mass and charge balanced 。 2+ assume low pH, use H (a) Fe(Cr0H (b) HS + MnO4 = S(s) +MnO2(s) (c) CH3OH + O2 = CO2 + H2O to balance assume high pH, use OH to balance assume low pH, use H' to balance

Survey of Oxidation and Reduction Reactionsi 2. Use the onidation state rules to assign oxidation states for the indicated atoms in each oidizing agent and its product (Part A) Atom Ouidizing Oridation State Product Osidation State Agent Mn H,o, H,O 2. Cl oc- 3. Fill in the blanks to show the number of electrons involved in each half-reaction for the onidizing agents identified in Question 2 2. 4. Combine the osidation hald-reaction for Fe (see the Backgrwand section) with the appropriate half-reaction from (b) bydrogen peroside, and (e) hypochlorite ion. S. Choose the correct terms to complete the following sentence: A(n) oxidizing/reducing agent is a sulbstance that causes the oxidation/reduction of another reactant in a redox reaction. The oxidation state of the oxidizing agent increases/decreases and the oxidizing agent itself undergoes oxidation/reduction during the reaction. 6. How can potassium ferricyanide be used to confirm that Fe ions have been reduced to Fe in Part B 7, uct wilace ion Sulfite ion (SO,, ) is a strong reducing agent. Assign oxidation states to the sulfur atom in SO,-and its prod- & Fill in the blank to show the number of electrons in the following half-reaction. so,2-(aq) + H,OD+ so,2-(aq) + 2H.(aq) + 다. c Write the balanced equation for the overall redox reaction of Fe with sulfte ion.