Molecular Polarity - Ch3_BondingTheory4.pptx PDF

Molecular Polarity  VSEPR shapes affect whether or not an entire molecule is polar or non-polar  H2O has polar covalent bonds Is also a polar molecule  CCl4 has polar covalent bonds Is a non-polar molecule  Does NOT apply to ionic bonds  Molecular polarit...

Molecular Polarity  VSEPR shapes affect whether or not an entire molecule is polar or non-polar  H2O has polar covalent bonds Is also a polar molecule  CCl4 has polar covalent bonds Is a non-polar molecule  Does NOT apply to ionic bonds  Molecular polarity is determined by the sum of the molecule’s bond polarity vectors  Labelling Bond Polarity  Identify electronegativities δ = partial charge δ+ = less electronegative δ – = more electronegative 2.2 3.2  Bond dipole Shows direction of polarity Arrow points to more electronegative end  Determine the direction of polarity & draw the diploe: C – Cl I -P N –O  Presence of polar covalent bonds May / may not create a polar molecule  Presence of non-polar covalent bonds May / may not create a polar molecule Need to examine shape of molecule to determine (VSEPR) Consider bond dipoles as vectors Ex. CO2 vs. CH4 vs. H2O NON-POLAR NON-POLAR MOLECULE Polar bonds MOLECULE Polar bonds Equal but opposite pulls on e- Equal but opposite pulls on e- POLAR MOLECULE! Polar bonds Equal but NOT opposite pulls on e-  X-components cancel Y-components add together Resultant (net) dipole Towards oxygen You Try….  NH3 vs. BF3  What about PH3?  Workbook #11  General rules: C  Trigonal Tetrahedral Pyramidal N, All same atoms P Polar Non-polar molecules 3 same / 1 different  Trigonal Planar Polar B Trigonal planar Non-polar (double bond with another C) O Non-polar Tends to make a molecule polar Exception – CO2  Importance? Application? Solubility Why doesn’t water get out oil stains? Why do oil and water form layers when mixed? “Like dissolves like” Polar with polar Non-polar with non-polar How do detergents work?