To be viewed with PowerPoint. Animation doesn’t work otherwise. Office XP To be viewed with PowerPoint. Animation doesn’t work otherwise. Ken Rogers kenrogers2@aol.com
Voltaic Cells Ken Rogers Miami Killian
? 1M ZnSO4 1M CuSO4 salt bridge voltmeter 2 possible rxns here Na+ Cu Cl- porous plugs Zn+2 SO4-2 Cu+2
reduction reduction Zn+2 + 2e- a Zn -0.76V Cu+2 + 2e- a Cu +0.34V Zn a Zn+2 + 2e- -0.34V Cu a Cu+2 + 2e- oxidation Zn Cu porous plugs SO4-2 Zn+2 SO4-2 Cu+2
Oxidation occurs at the Anode Reduction occurs at the Cathode Zn a Zn+2 + 2e- +0.76V Cu+2 + 2e- a Cu reduction +0.34V Cu+2 + Zn a Cu + Zn+2 1.10V Oxidation occurs at the Anode Reduction occurs at the Cathode
Direction of electron flow? 1.10V oxidation reduction _ + Anode Cathode Zn Cu Cu e- e- SO4-2 Zn+2 SO4-2 Zn+2 Cu+2
What’s the reaction with the highest potential? To calculate the voltage, you need to figure out the two half reactions. What’s the reaction with the highest potential? ? voltmeter Ag Al Ag+1 Al+3 NO3-1 NO3-1 NO3-1 NO3-1 1M AgNO3 1M Al(NO3)3
? reduction Ag+1 + e-1 a Ag 0.80 V Al+3 + 3e-1 a Al -1.66 V -0.80 V Ag a Ag+1 + e-1 1.66 V Al a Al+3 + 3e-1 oxidation voltmeter Ag Al Ag+1 Al+3 NO3-1 NO3-1 NO3-1 NO3-1 1M AgNO3 1M Al(NO3)3
Voltage is not multiplied by 3. 3 ( ) Ag+1 + e- a Ag 0.80 V Voltage is not multiplied by 3. Voltage, like density is an intensive property. 1.66 V Al a Al+3 + 3e-
3Ag+1 + 3e- a 3Ag 0.80 V 1.66 V Al a Al+3 + 3e- 3Ag+1 + Al a 3Ag + Al+3 2.46 V
Direction of electron flow? Where are the electrons being produced? 2.46 V Ag+1 + e-1 a Ag Al a Al+3 + 3e-1 Ag Al Ag+1 Al Al+3 NO3-1 Ag e- e- e- Ag Ag+1 Ag NO3-1 Ag+1 NO3-1 Al+3 NO3-1 1M AgNO3 1M Al(NO3)3
Oxidation occurs at the Anode Reduction occurs at the Cathode
Identify the anode and cathode. 2.46 V Al a Al+3 + 3e-1 Ag+1 + e-1 a Ag reduction oxidation Cathode Anode
Direction of ion flow in salt bridge? 2.46 V Na+ NO3-1 Cathode Anode
2.46 V Ag+1 + e-1 a Ag Al a Al+3 + 3e-1 Ag Al Ag+1 Al Al+3 NO3-1 Ag Ag Na+ NO3-1 Ag Al Ag+1 Al Al+3 NO3-1 Ag e- e- e- Ag Ag+1 Ag NO3-1 Ag+1 neutral Al+3 neutral NO3-1 NO3-1 NO3-1 NO3-1 1M AgNO3 1M Al(NO3)3
Anions flow towards the Anode Cations flow towards the Cathode
Direction of ion flow in salt bridge? 2.46 V Na+ NO3-1 Cathode Anode Al+3 NO3-1
Anode is the negative electrode Cathode is the positive electrode
2.46 V _ + Cathode Anode
So, what’s this? NaCl + Assault and battery