Lecture 30 Objectives a Identify reduction components using valence diagrams b Free energy change of redox reactions c Utilize table of reduction potential d Components of galvanic cell a1 Using the diagram to the right identify the best oxidizing agent and describe how it was selected a2 Identify the best reducing agent and describe how it was selected V has highest E a3 Why is the 2 2 reaction below spontaneous V W V W Ox number is dec V W a4 V Why the reaction 2 isW V below W2 non spontaneous Ox num are changing but being canceled out 1 Lecture 30 Objectives b1 The formula for determining the free energy of a redox reaction is shown below Define each of the variables and give units G n F Ecell energy change on e moles trans Faraday Constant voltage b2 What is the sign of Ecell for a spontaneous reaction Neg What is the sign of Ecell for a non spontaneous reaction Pos c1 What is the 0 reaction on the Reduction Table Non spont c2 The best reducing agent is located on the left of the table and has 0 valence orbitals c3 The best oxidizing agent is located on the right of the table and has 2 valence orbitals c4 Spontaneous redox reactions occur when a chemical on the right of the table reacts with a chemical on the left of the table 2 Lecture 30 Objectives d Complete the following statements regarding a galvanic cell Reduction occurs at the cathode which has a sign on the voltmeter Oxidation occurs at the anode which has a sign on the voltmeter Electrons travel from the anode to the cathode As the redox reaction progresses the cathode electrode decreases in size and the concentration of redox ion cathode As the redox reaction progresses the anode electrode increases in size and the concentration of redox ion anode The salt bridge cations migrate towards the cathode and the anions migrate towards the anode 3 2EnterRquestion Q30 1 S2 text R S A Spontaneous B Non spontaneous R S 4 EnterRquestion Q30 2 S4 text R2 S2 A Spontaneous B Non spontaneous R S 5 Enter question Q30 3 R2 S text R S2 A Spontaneous B Non spontaneous R S 6 Q30 4 Choose the best oxidizing agent A R2B R C R2 D S E S4 R S 7 Q30 5 Choose the best reducing agent A R2B R C R2 D S E S4 R S 8 Q30 6 What change in potential does an electron experien when it moves from an initial potential of 0 8 V to a final potential at 0 3 V Is the change spontaneous or non spontaneous Enter question text A 1 1 V non spontaneous B 1 1 V spontaneous C 0 5 V non spontaneous D 0 5 V spontaneous E 0 5 V non spontaneous DEcell Efinal Einitial G n F Ecell 9