Chapter 2_part 2

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Chapter 2_part 2

• Functional Groups

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Ether

• General formula R-O-R or R-O-R
• where R or R may be an alkyl
• Name ends with ether

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2.9 Amines

• Organic derivatives of ammonia (NH3)
• N of amines can be considered as sp3 hybridized
• Name ends with amine as part of root

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2.10 Aldehydes and Ketones

• Both contain carbonyl group
• Carbon has a double bon to oxygen
• Trigonal planar arrangement

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Aldehydes and Ketones

• General formula

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2.11 Carboxylic Acids, Esters, and Amides

• Carbonyl that is bonded to an oxygen or nitrogen
  atom

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Esters

• general formula RCO2R (or RCOOR)
• Carbonyl is bonded to an alkoxyl (-OR ) group

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Ester

• Can be made from a carboxylic acid and an alcohol
  through the acid-catalyzed loss of a molecule of
  water

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2.11 Amides

• General formula RCONH2, RCONHR or RCONRR
• Carbonyl group is bonded to a nitrogen atom
  bearing hydrogen/or alkyl groups

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2.12 Nitriles

• IUPAC nomenclature addition of suffix nitrile
  to the root name

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2.14 Physical Properties and Molecular Structure

• melting point (MP)
• boiling point (BP)
• measure the temperature at which transitions
  occurs between phase
• physical properties

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Ion-Ion Forces

• Melting point of a substance is the temperature
  at which an equilibrium exists between solid and
  liquid state
• Ionic compounds are held together by the ion-ion
  force
• Charges attraction
• Symmetrical molecule has higher MP

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Ion-Ion forces

• Boiling point temperature at which a liquid
  becomes gas
• Larger molecular weight, the more interaction
  sites, thus more bonds to be broken
• Heavier substance, the greater the energy needed
  to give the molecules sufficient impetus to break
  these intermolecular forces
• ? higher BP
• Branches molecules have lower BP

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Dipole-Dipole Forces

• Compounds with different polarity will have a
  dipole-dipole moment
• Causes the molecule to orient themselves so the
  positive end is directed toward the negative end

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Hydrogen bond

• Polar molecules, such as water molecules, have a
  weak, partial negative charge at one region of
  the molecule (the oxygen atom in water) and a
  partial positive charge elsewhere (the hydrogen
  atoms in water).

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Hydrogen bond

• The attraction created by hydrogen bonds keeps
  water liquid over a wider range of temperature
  than is found for any other molecule its size.
• The energy required to break multiple hydrogen
  bonds causes water to have a high heat of
  vaporization that is, a large amount of energy
  is needed to convert liquid water, where the
  molecules are attracted through their hydrogen
  bonds, to water vapor, where they are not

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van der Waals forces
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van der Waals Forces

• Also known as London forces or dispersion forces
• is the attractive or repulsive force between
  molecules other than those due to covalent bonds
  or to the electrostatic interaction of ions with
  one another or with neutral molecules
• why does methane melt and boil at low
  temperature?
• Why does methane, a nonionic, nonpolar substance,
  become solid and liquid at all?

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van der Waals forces

• Nonpolar compound has weak intermolecular forces,
  used less energy
• Boil at low temp
• Heavier molecules required greater amount of
  energy to escape from liquid to gaseous
• Larger surface, greater van der Waals interaction

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Solubilities
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Solubilities

• In the process of dissolving, molecules or ions
  must be separate from each other
• Energy required to overcome lattice energies and
  intermolecular or interionic attractions come
  from the formation of new attractive forces
  between solute and solvent
• Water is highly polar and is capable to form
  strong hydrogen bonds
• Polar and ionic compounds tend to dissolve in
  polar solvent
• Like dissolves like

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Solubilities

• Long carbon chain ? less soluble
• If its an alcohol then we must consider the two
  ends of the molecule
• Hydrophilic water loving
• Hydrophobic water avoiding