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Chapter 8 Even Problems
40. Which compound in each of the following pairs of ionic substances has the most exothermic
lattice energy? Justify your answers.
a. LiF, CsF
b. NaBr, NaI
c. BaCl2, BaO
d. Na2SO4, CaSO4
e. KF, K2O
f. Li2O, Na2S
52. Estimate H for the following reaction using bond energies.
O
C2H4 + O3 → H3C–C–H + O2
64. Write Lewis structures that obey the octet rule for each of the following molecules and ions.
a. SO42–, PO43–, ClO4–
b. SO32–, PO33–, ClO3–
c. ClO2–, SCl2, PCl2–
d. Considering your answers to parts a, b, and c, what conclusions can you draw concerning
structures containing the same number of atoms and the same number of valence electrons?
68. Some of the important pollutants in the atmosphere are ozone (O3), sulfur dioxide, and sulfur
trioxide. Write Lewis structures that obey the octet rule for these three molecules. Show all
resonance structures where applicable.
92. Write Lewis structures and predict whether each of the following is polar or nonpolar.
a. HOCN (exists as HO–CN)
d. CF2Cl2
b. COS (O is the central atom)
e. SeF6
c. CO2
f. H2CO (C is the central atom)
94. Write a Lewis structure and predict the molecular structure and polarity for each of the
following sulfur fluorides: SF2, SF4, SF6, and S2F4 (exists as F3S–SF). Predict the F–S–F bond
angles in each molecule.