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Hon Chem Ch 20 Pg 655 Electrochemical Cells . AKA batteries Pg 643 Zn is good reducing agent (gets oxidized, loses electrons, ox# goes up) Cu is good oxidizing agent (gets reduced, gains electrons, ox# goes down). Parts and Types of Batteries Pg 656-9. 1. Zinc-Carbon Dry Cell
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Hon Chem Ch 20 Pg 655Electrochemical Cells • AKA batteries • Pg 643 Zn is good reducing agent (gets oxidized, loses electrons, ox# goes up) • Cu is good oxidizing agent (gets reduced, gains electrons, ox# goes down)
Parts and Types of BatteriesPg 656-9 1. Zinc-Carbon Dry Cell a. big, used in flashlights, C and D batteries b. Zn container – anode, negative, becomes + as loses electron c. C rod in center – cathode, + bump on end of battery, becomes negative as gains electrons
2. Alkaline Batteries a. smaller, AA and AAA, cameras, remotes b. Zn and KOH instead of Zn and C • Hg Batteries a. tiny, hearing aids, watches b. Zn, KOH, Steel, HgO
Corrosion and PreventionPg 661-2 • Fe is oxidized, loses electrons, forms rust • Salt and acid speed up the oxidation • Zn coating prevents oxidation due to Pg 643, called galvanizing • Electric potential difference = volts (how hard electricity pushes thru wire)
Recharging BatteriesPg 667-9 • Voltaic cell – battery making electricity, anode gives electrons to cathode • Electrolytic cell – battery when being recharged, storing electricity, direct current source forces cathode to give electrons back to anode • DC sources - wall charger with diode to change AC to DC, car alternator, other battery (jumping a car) • Can be recharged as long as enough products to act as reactants to reverse reaction, corrosion is loss of products/reactants so can’t recharge after corroded Pg 669**do redoxrxn for car battery