Chapter 18: The Representative Elements

Tin forms compounds in the +2 and +4 oxidation states. Therefore, when tin reacts with fluorine, two products are possible. Write balanced equations for the production of the two tin halide compounds and name them.

Write equations describing the reactions of$\mathit{S}$ with each of the following:role="math" localid="1663850037443" $\mathit{C}{\mathit{l}}_{\mathbf{2}}\mathbf{,}{\mathit{O}}_{\mathbf{2}}$, and$\mathit{H}\mathit{C}\mathit{l}$

The compound $P{b}_3{O}_4$ (red lead) contains a mixture of lead (II) and lead (IV) oxidation states. What is the mole ratio of lead (II) to lead (IV) in$P{b}_3{O}_4$ ?

The major industrial use of hydrogen is in the production of ammonia by the Haber process:

${\mathbf{\text{3H}}}_{\mathbf{\text{2}}}{\mathbf{\text{(g) +N}}}_{\mathbf{\text{2}}}\mathbf{\text{(g)}}\mathbf{\to }{\mathbf{\text{2NH}}}_{\mathbf{\text{3}}}\mathbf{\text{(g)}}$

a. Using data from Appendix 4 , calculate$\mathbf{∆}{\mathit{H}}^{\mathbf{0}}$ ,$\mathbf{∆}{\mathit{S}}^{\mathbf{0}}$ , and $\mathbf{∆}{\mathit{G}}^{\mathbf{0}}$for the Haber process reaction.

b. Is this reaction spontaneous at standard conditions?

c. At what temperatures is the reaction spontaneous at standard conditions? Assume that$\mathbf{∆}{\mathit{H}}^{\mathbf{0}}$ and$\mathbf{∆}{\mathit{S}}^{\mathbf{0}}$ do not depend on temperature.

The resistivity (a measure of electrical resistance) of graphite is (0.4 to $5.0)\times {10}^{-4}ohm\times cm$ in the basal plane. (The basal plane is the plane of the six-member rings of carbon atoms.) The resistivity is 0.2 to$1.0ohm\times cm$ along the axis perpendicular to the plane. The resistivity of diamond is${10}^{14}$ to${10}^{16}ohm\times cm$ and is independent of direction. How can you account for this behaviour in terms of the structures of graphite and diamond?

The oxyanion of nitrogen in which it has the highest oxidation state is the nitrate ion $\left(N{O^{-}}_3\right)$. The corresponding oxyanion of phosphorus is$P{O}_4^{3-}$ . The$N{O}_4^{3-}$ ion is known but is not very stable. The $P{O}_4^{3-}$ ion is not known. Account for these differences in terms of the bonding in the four anions.

Using data from Appendix 4, calculate $∆H^{\circ }$, $∆S^{\circ }$, and $∆G^{\circ }$ for the reaction

${\text{N}}_2\left(g\right)+{\text{O}}_2\left(g\right)\to 2\text{NO}\left(g\right)$

Why does the $\mathbf{NO}$formed in an automobile engine not readily decompose back to ${\text{N}}_2$ and ${\text{O}}_2$in the atmosphere?

Table 18.14 lists some common nitrogen compounds having oxidation states ranging from 23 to 15. Rationalize this spread in oxidation states.

What is nitrogen fixation? Give some examples of nitrogen fixation.

Elemental nitrogen exists as ${\mathit{N}}_{\mathbf{2}}$, whereas in the gas phase the elements phosphorus, arsenic, and antimony consist of${\mathbf{P}}_{\mathbf{4}}$,$\mathit{A}{\mathit{s}}_{\mathbf{4}}$, and$\mathit{S}{\mathit{b}}_{\mathbf{4}}$molecules, respectively. Give a possible reason for this difference between${\mathit{N}}_{\mathbf{2}}$and the other Group$\mathbf{5}\mathit{A}$elements.