Chemistry 236 Worksheet

  1. Explain what is meant by: a) an ionic bond, b) a polar covalent bond, and c) a non-polar covalent bond. Give examples for each.
  2. Draw Lewis dot structures for the following formulas:
    a) H3COH b) H2CO c) C02 d) C2H6
    e) C2H4 f) C2H2 g) 03 h) HN03
    Compound C-C bond length
    CH3-CH3 1.54
    H2C=CH2 1.33
    HCΞHC 1.20

    a) What is the hybridization of each of the, carbons in ethane- ethylene and acetylene? 
    b) Why do the carbon-carbon bond lengths decrease going from ethane to ethylene to acetylene? 
    c) What is the hybridization of each of the carbon atoms in allene, H2C=C=CH2
    d) What would you expect for the carbon-carbon bond length of allene? 
    e) Draw a 3-dimensional representation of allene showing the carbon-carbon σ and π molecular orbitals.
    f) Is allene a 'flat molecule' (do all the hydrogens lie in one plane)? Why or why not?
  4. Draw all possible line-bond structures that are consistent with the valence rules for the following molecular formula: 
    a) C3H7F  b) C2H60  c) C2H40  d) C3H9
  5. Calculate formal charges for each non-hydrogen atom in the following molecules:
    a) Molecule b) Molecule c) Molecule

  6. Make 3-dimensional drawings for non-planar molecules and show the direction of the expected dipole moment for each of' these molecules: 
    a) H2CCl2     b) H2C=CC12     c) C12C=CC12     d) HCC13     e) Molecule
  7. Define Lewis acids and Lewis bases. 
  8. Which of the following are Lewis acids and which are Lewis bases? 
    a) (H3C)3N:   b) BF3   c) AlC13   d) (H3C)3P:   e) (C2H5)2
  9. Convert the following structures into skeletal drawings: 
    a) Molecule b) Molecule

  10. Convert the following into Kekule structures: 
    a) Molecule b) Molecule