Chemistry 100

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http//enstrophy.colorado.edu/mohseni/ASEN5519Spr
ing2004/TypesOfChemicalBonds1.html
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London dispersion forces

• All molecules exhibit these forces.
• Due to temporary and induced dipoles.
• Strongest IMFs for non-polar molecules
• Examples include nitrogen (N2) and methane (CH4).
  

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Dipole-dipole interactions

• Polar molecules exhibit these forces.
• Due to permanent dipoles.
• Stronger IMFs for than LDFs (given similar sized
  molecules).
• Examples include hydrogen chloride (HCl) and
  water (H2O which exhibits a special kind of
  dipole-dipole interaction).

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Ion-ion interactions

• Ionic compounds exhibit these forces.
• Due to ions.
• Strongest of the IMFs (given similar sized
  molecules).
• Example includes sodium chloride (NaCl).

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Question 1

• Which of the following molecules exhibits
  dipole-dipole interactions?
• a) OF2
• b) SF6
• c) XeF4
• d) C2H2
• e) At least two of the above molecules (a-d)
  exhibit dipole-dipole interactions.

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Question 2

• Which of the following molecules would be
  expected to have the lowest boiling point?
• a) C4H10
• b) NH3
• c) H2O
• d) C2H6
• e) I do not know.

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Question 3

• Methane (CH4) is a gas, but carbon tetrachloride
  (CCl4) is a liquid at room conditions. Which of
  the following explains this phenomenon?
• a) CCl4 is a polar molecule and CH4 is not.
• b) CCl4 and CH4 have different geometries and
  shapes.
• c) CH4 exhibits hydrogen bonding and CCl4 does
  not.
• d) Cl is more electronegative than H.
• e) None of the above explanations explains this.

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Question 4

• Which of the following molecules would be
  expected to have the highest melting point?
• a) CO2
• b) N2
• c) SO2
• d) H2
• e) H2O