Chem 1100 Lecture 17Outline of Last Lecture I. RadioactivityII. Carbon DatingIII. HistoryIV. Nuclear Weapons ProliferationOutline of Current Lecture I. Energy/ElectricityII. BatteriesIII. Why not use batteries to power everything?Current LectureI. Energy/Electricitya. Power Plantsi. Burn coal heat water turn turbine electricityb. Batteryi. Stored energy, converts chemical to electricalc. Galvanic Cellsi. Chemical electricald. Electrolytic Celli. Electrical chemicale. Electricityi. The flow of electrons.ii. Chemistry: making and breaking chemical bonds.iii. Bonds = electronsiv. Chemical reactions: some involve sharing electrons and others involve transferring electrons to produce electricity.f. Oxidation ReactionThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.i.g. Half Reactionsi. 2 Na + Cl2 2NaClii. Shows electron transfer: 2Na 2Na+ + 2e- Na loses e- (oxidation)iii. Cl2 + 2e- 2Cl- Cl gains e- (reduction)II. Batteriesa. Oxidation Is Loss Reduction Is Gainb. Nickel-Cadmium Batteryi. 2Ni+3 + Cd 2Ni+2 + Cd+2ii. Cd Cd+2 + 2e- (Oxidation)iii. 2Ni+3 + 2e- 2Ni+2 (Reduction)c. How to Make Electricity: i. Separate the half reactionsii. Connect with a wireiii. Only way for the reaction to go is for the electron to run through the wireiv. The electron flow = the electric currentd. Electrodesi. Electrical conductors – sites of the reactionsii. Cathode: reduction occurs – electrons gainediii. Anode: oxidation occurs – electrons loste. Voltagei. Ease of anode electron releaseii. Ease of cathode electron absorptioniii. Units are called Voltsf. Salt Bridgei. Allow ions to transfer through them. It’s made of ionic compounds that allow ions to travel.ii.g. What do we want from our batteries?i. High voltage (energy efficient), cheap, long lasting, safe handling and disposal, small, & lighth. Alkaline Batteryi. Storage Batteryi. We use them in our cars.ii. They have 6 cells inside them with each capable of putting out 2 volts of energy.iii. Sores electrical energy.iv. Ex: Lead-acidv. Six 2.0 V cells 12.0 Vj. Pb-Acidi. Long lastingii. Rechargeable iii. Power starter, lights, radio, etc.iv. Alternator rechargesv. It’s toxic and heavyk. Improving Batteriesi. Safe disposal – phase out of mercury and lead batteriesii. Light, more dependableiii. Reachargeableiv. Nickel-metal hydride (NiMH), Lithium-ion (Li-ion), replace alkalineIII. Why not use batteries to power everything?a. Efficiencyi. Power plants: 30-40%ii. Batteries: 90% b. It would be very expensive to power everything with batteries because batteries are expensive to make and also people don’t always dispose of them appropriately.i. Rechargeable batteries don’t last forever so disposal is still an issue.ii. Where does the power come to recharge batteries? Power plant.c. Alternative to batteriesi. Fuel Cells: 1. Chemical energy is turned into electrical energy. 2. No fire/explosion3. Fuel and oxidant supplied, “waste” expelled continuously4. Half reactions
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