Problem 126b
(b) What are they in graphite (in one sheet)?
Problem 126c
(c) What atomic orbitals are involved in the stacking of graphite sheets with each other?

Problem 127
Employing the bond enthalpy values listed in Table 8.4, estimate the molar enthalpy change occurring upon (a) polymerization of ethylene. (b) formation of nylon 6,6. (c) formation of polyethylene terephthalate (PET).
Problem 128a
Although polyethylene can twist and turn in random ways, the most stable form is a linear one with the carbon backbone oriented as shown in the following figure:

The solid wedges in the figure indicate bonds from carbon that come out of the plane of the page; the dashed wedges indicate bonds that lie behind the plane of the page. (a) What is the hybridization of orbitals at each carbon atom? What angles do you expect between the bonds?
Problem 129a
(a) In polyvinyl chloride shown in Table 12.6, which bonds have the lowest average bond enthalpy?

Problem 130a
Silicon has the diamond structure with a unit cell edge length of 5.43 Å and eight atoms per unit cell. (a) How many silicon atoms are there in 1 cm3 of material?
Problem 131a,c
One method to synthesize ionic solids is by the heating of two reactants at high temperatures. Consider the reaction of FeO with TiO2 to form FeTiO3. Determine the amount of each of the two reactants to prepare 2.500 g FeTiO3, assuming the reaction goes to completion. (a) Write a balanced chemical reaction. (c) Determine the moles of FeTiO3.
Problem 131b
One method to synthesize ionic solids is by the heating of two reactants at high temperatures. Consider the reaction of FeO with TiO2 to form FeTiO3. Determine the amount of each of the two reactants to prepare 2.500 g FeTiO3, assuming the reaction goes to completion. (b) Calculate the formula weight of FeTiO3.
Problem 131d
One method to synthesize ionic solids is by the heating of two reactants at high temperatures. Consider the reaction of FeO with TiO2 to form FeTiO3. Determine the amount of each of the two reactants to prepare 2.500 g FeTiO3, assuming the reaction goes to completion. (d) Determine moles and mass (g) of FeO required.
Ch.12 - Solids and Modern Materials
