Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Hydrocarbon Names • Saturated hydrocarbons (alkanes) have general formula CnH2n+2 • • • • • CH4 methane C2H6 ethane C3H8 propane C4H10 butane C5H12 pentane • • • • • C6H14 hexane C7H16 heptane C8H18 octane C9H20 nonane C10H22 decane Nonpolar bonds, only London dispersion forces Acid Names • All acid formulas start with H • Binary acid names start with “hydro”, change root ending to “ic” and add “acid”. • HCl hydrochloric acid • HCN hydrocyanic acid • HBr • HI Acid Names • Binary acids are only named as acids when in water solution. • Dry compounds are named as molecular compounds • Example: HCl is hydrochloric acid in water solution, but hydrogen chloride as a free gas Ternary acid names • Use root of anion name followed by “-ic” or “-ous” and “acid” • “-ic” is used with anions ending in “-ate” and “-ous” is used for “-ite”. • H2SO4 sulfuric acid • H3PO4 • HNO3 • HClO2 Exceptions to Octet rule • Odd electron molecules (ex. NO2) • Electron deficient molecules (ex. BF3) • Expanded octet - only for period 3 and higher (ex. SF6, PCl5, SO4-2) Bond Polarity • Bonds are polar when there is an unequal distribution of electrons in a bond Bond Polarity • Polar bonds are formed when two atoms of unequal electronegativity are bonded • The bond has a “dipole moment” because of the d+ and d- poles Bond polarity • • • • EN difference of 0-0.4: nonpolar covalent EN difference of >0.4-1.4: polar covalent EN difference of >1.4: ionic bond Greater dipole-dipole interactions means greater mp and bp • Example: propane (C3H8, 44amu) has boiling point -42ºC, dimethyl ether (CH3OCH3, 46amu) has bp -23ºC Molecular geometry • VSEPR = valence shell electron pair repulsion • Bonding and nonbonding pairs will arrange themselves around an atom so that they are as far from each other as possible • 2 pairs - BeCl2 • Linear geometry, bond angle = 180º Molecular geometry • • • • • • Three pairs - BH3, CH2O Trigonal planar geometry, bond angle 120º Four pairs - CH4 Tetrahedral geometry, bond angle = 109.5º Five pairs - PCl5 (expanded octet) Trigonal bipyramid geometry, bond angles = 120º and 90º Molecular geometry • Six pairs - SF6 • Octahedral geometry, bond angles 90º Nonbonding Pairs • Two bonding, one nonbonding - NO2• Bent geometry (anything with two bonding pairs and at least one nonbonding pair) • Bond angle <120º, since nonbonding pair is larger Molecular geometry • Three bonding, one nonbonding (NH3) • Trigonal pyramidal geometry, <109.5º bond angle Hybridization • Recombination of s and p orbitals to produce equivalent bonding orbitals • Two atoms and/or lone pairs: sp hybridization Hybridization • Three atoms and/or lone pr.: sp2 • Four atoms and/or lone pr.: sp3