1、redox class #2 ob:assigning oxidation numbers plusbatteries (voltaic cells)if you read the diary this should be easy, if you didnt yet read the diary, ask yourself why?take better care of yourself, youre worth it.ions have easy oxidation numbers, its just the charge of the ion. for examples:the oxid

2、ation number for the sodium cation is +1for the chloride anion it is -1for the sulfate anion (table e), its -2for magnesium cation it is +2for all atoms (including the honclbrif twins) it is zero, because they have no charge.inside molecules, like carbon dioxide (no ions) there are still oxidation n

3、umbers.take your reference tables out now, periodic table, please.what are the oxidation numbers for each atom in each molecule or ion listed?co2cocacl2no2pcl3pcl5h2so4cr2o7-2nbbr5what are the oxidation numbers for each atom in each molecule or ion listed?co2 c+4 o-2co c+2 o-2cacl2 ca+2 cl-1cl-1no2

4、n+4 o-2 o-2pcl3 p+3 cl-1cl-1cl-1pcl5 p+5 cl-1cl-1cl-1cl-1cl-1h2so4 h+1h+1s+6 and 4o-2cr2o7-2 2cr+6 and 7o-2nbbr5 nb+5 and 5br-1demo: single replacement (redox too) reactionsilver nitrate solution plus copper forms copper (ii) nitrate solution and silverwrite a balanced chemical equation now.what spe

5、cies is oxidized? _what species is reduced? _ name the spectator ion_write the half reactions and the net ionic equation now. ox: _ red: _net: _demo: single replacement (redox too) reactionsilver nitrate solution plus copper forms copper (ii) nitrate solution and silverwrite a balanced chemical equa

6、tion now.what species is oxidized? cuwhat species is reduced? ag+1 name the spectator ion no3-1write the half reactions and the net ionic equation now. ox: cu cu+2 + 2e- red: 2ag+1 + 2e- 2ag net: cu + 2ag+1 cu+2 + 2ag 2agno3(aq) + cu(s) cu(no3)2(aq) + 2ag(s)a battery is a voltaic cell, it spontaneou

7、sly produces electricity. electricity is the flow of electrons, which can do work like light up your bulb, or start your car, or what ever. batteries are cute, and neatly packaged, but to learn how they work we sort of have to take them apart to see the details.on this next slide, there is a big (mo

8、stly ugly looking at first) diagram. you will have to draw it over and over, and youll like it, but probably not right now. so, let me hand you one to start, then you can recopy it over and over. bulbwere going to label this now. it shows two beakers of solution, with a piece of metal in each one, c

9、onnected by a wire. theres also a glass tube with a solution in it, and cotton balls (not drawn) connecting the 2 solutions. at top is a bulb, which would light up if electricity goes through the wire. bulbznso4(aq)cuso4(aq)zn cusalt bridgek2so4(aq)take out table j nowbulbznso4(aq)cuso4(aq)zn cusalt

10、 bridgek2so4(aq)first, decide which metal is going to oxidize and which will be forced to reduce, then we will label this diagram completely.next slide, write the half reactions and net ionic equation.bulbznso4(aq)cuso4(aq)zn cusalt bridgek2so4(aq)write the half reactions where they belong, then the

11、 net ionic equation too. ox: _ red: _net ionic equation: _bulbznso4(aq)cuso4(aq)zn cusalt bridgek2so4(aq)write the half reactions where they belong, then the net ionic equation too. ox: zn zn+2 + 2e- red: cu+2 + 2e- cunet ionic equation: zn + cu+2 zn+2 + cujust to prove i am not afraid,this is my so

12、n playing lacrosse.he picked his own number, and i had no trouble with any triskaidekaphobia at all. bulbznso4(aq)cuso4(aq)zn cusalt bridgek2so4(aq) oxidationreductionzn+2cu+ 2electron flowelectron flow+-the solutions become charged immediately, stopping the flow of electrons. what will we do?bulbzn

13、so4(aq)cuso4(aq)zn cusalt bridgek2so4(aq) oxidationreductionzn+2cu+ 2electron flowelectron flow+-so4-2k+1the ions of the salt bridge balance out the electrical potential that builds up, letting the electricity flow and flow!bulbpbcl2(aq)mg(oh)2(aq)pbmgsalt bridge nacl(aq) completely label this, ox side, red side, anode, cathode, direction of electrons, directions of salt ions, and think about the 3 reasons that this battery would (will) die.bulbpbcl2(aq)mg(oh)2(aq)pbmgsalt bridge nacl(aq)