Principles of Chemistry II © Vanden BoutThe rest of the SemesterAll of ChemistryTodayGroups 1V-VIII Principles of Chemistry II © Vanden BoutC60 + nanotubes"wrapped up" graphite Principles of Chemistry II © Vanden BoutWhy are we excited about C60 and nanotubesConductingSoluble in different solventsStrong materialsMight be useful for electronics, drug delivery, sensors..."Nanobuilding blocks" Principles of Chemistry II © Vanden BoutMetals, Insulators, SemiconductorsSemiconductors, bands are close but there is a gap.Need thermal energy to move into unoccupied statesOr dopant (add or remove an electron)Principles of Chemistry II © Vanden BoutWhy is Silicon semiconductingwhile Diamond is an insulator (same structure)A. Silicon is larger so their is less interaction between the atoms and a lower splitting between the levelsB. Silicon is smaller so their is less interaction between the atoms and a lower splitting between the levelsC. Silicon is larger so their is more interaction between the atoms and a greater splitting between the levels Principles of Chemistry II © Vanden BoutGraphite is sp2 carbons Principles of Chemistry II © Vanden BoutDiamond and Silicon all sp3 Principles of Chemistry II © Vanden BoutCarbon (diamond)close atomic spacing leads to strong orbital overlap and large splitting between the bonding and antibonding bandsINSULATORSiliconlarger atomic spacing leads to weak orbital overlap and a small splitting between the bonding and antibonding bandsSEMI-CONDUCTORPrinciples of Chemistry II © Vanden BoutHow might you "add an electron" to silicon? A. Substitute a P for a silicon atom in the solidB. Substitute a B for a silicon atom in the solidC. Substitue a C for a silicon atom in the solid Principles of Chemistry II © Vanden BoutGroup III will take an electron and "leave" a positive charge in the Si lattice P-doping (P = positive)Group V will "give an electron" and resulting in a negative charge in the Si lattice N-doping (N = negative) Principles of Chemistry II © Vanden Bout Principles of Chemistry II © Vanden BoutLast but not leastSilicone (rubber)Back bone...-Si-O-Si-O-Si-O-Si-O-.....Silicon can form two more bondsAdd various organic molecules for different propertieshousehold "caulk", silly putty, ....Principles of Chemistry II © Vanden BoutGroup V, VI, VIIFour very important chemicalsPhophoric Acid (H3PO4)Ammonia (NH3)Sulfuric Acid (H2SO4)Chlorine Gas (Cl2) Principles of Chemistry II © Vanden Bout4 Largest Production Chemical in the US Principles of Chemistry II © Vanden BoutSulfuric Acidused for lots of thingsSteel productionPhosphoric Acid ProductionRecovery of Ammonia in Steel ProductionIndustrialized Nation = Nation with lots of Sulfuric Acid Oxidizing AgentStrong AcidDehydrating Agent Principles of Chemistry II © Vanden BoutPrinciples of Chemistry II © Vanden BoutFertilizer Ammonia (N source) + Phosphoric Acid (P source)Ammonia used to make Nitric Acid (Ostwald Process)Sulfuric Acid used to make soluble phosphatesCa3(PO4)2 + 2H2SO4 2CaSO4 + Ca(H2PO4)2 2NH3(g) + 4O2(g) 2HNO3(aq) + 2H2O(l)HNO3(aq) + NH3(g) NH4NO3(s) Principles of Chemistry II © Vanden BoutAmmoniaProduction Haber Process3H2(g) + N2(g) 2NH3(g)catalystUsesWeak base (cleaning agent)Refrigerant (no longer used)fertilizernitric acid production Principles of Chemistry II © Vanden Boutthe Many NO compoundsN2O nitrous oxide (anaesthesia)NO neurotransmitterNO2 brown gas (NOx smog) also NO2 + OH = HNO3 = acid rain Principles of Chemistry II © Vanden BoutPrinciples of Chemistry II © Vanden BoutGroup VI Principles of Chemistry II © Vanden BoutImportant ChemistryNearly everything oxidizesLots of oxides very stableSulfur ChemistryH2SO4 very importantsee previous comments Principles of Chemistry II © Vanden BoutHalogensNeed one electron to make a nobel gas structureExcellent oxidizing agentsHigh ionization energiesSmall atoms and ionsLarge electronegativities Principles of Chemistry II © Vanden BoutPrinciples of Chemistry II © Vanden BoutLot's of Chemistry Principles of Chemistry II © Vanden BoutCl2 Used for halogenating compoundsalso used as a disinfectant Very poisonous (highly reactive)"pool chlorine" HOClCl2 + H2O HOCl + HCl"chlorine bleach"NaOClOCl- is a strong oxidizing agent Principles of Chemistry II © Vanden BoutFluorine unusualHigh charge density makes moreinsoluble saltsAlso fluorinated compounds tend to be very stable and can have unique propertiespolytetrafluoroethylene (Teflon) Principles of Chemistry II © Vanden BoutNobel GasesFew reactions. Nearly all with Xe (highly
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