91Ó°ÊÓ

Although phosphorus pentabromide exists in the vapor phase as \(\mathrm{PBr}_{5}\) molecules, in the solid phase the substance is ionic and has the structure \(\left[\mathrm{PBr}_{4}{ }^{+}\right] \mathrm{Br}^{-}\). What is the expected geometry of \(\mathrm{PBr}_{4}^{+} ?\) Describe the bonding to phosphorus in \(\mathrm{PBr}_{4}^{+}\)

Although phosphorus pentachloride exists in the vapor phase as \(\mathrm{PCl}_{5}\) molecules, in the solid phase the substance is ionic and has the structure \(\left[\mathrm{PCl}_{4}{ }^{+}\right]\left[\mathrm{PCl}_{6}^{-}\right] .\) What is the expected geometry of \(\mathrm{PCl}_{6}^{-}\) ? Describe the bonding to phosphorus in \(\mathrm{PCl}_{6}^{-}\).

Phosphorous acid, \(\mathrm{H}_{3} \mathrm{PO}_{3}\), is oxidized to phosphoric acid, \(\mathrm{H}_{3} \mathrm{PO}_{4}\), by hot, concentrated sulfuric acid, which is reduced to \(\mathrm{SO}_{2}\). Write the balanced equation for this reaction.

Phosphorous acid, \(\mathrm{H}_{3} \mathrm{PO}_{3}\), is oxidized to phosphoric acid, \(\mathrm{H}_{3} \mathrm{PO}_{4}\), by nitric acid, which is reduced to nitric oxide, NO. Write the balanced equation for this reaction.

According to an analysis, a sample of phosphate rock contains \(74.6 \% \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}\), by mass. How many grams of phosphoric acid, \(\mathrm{H}_{3} \mathrm{PO}_{4}\), can be obtained from \(30.0 \mathrm{~g}\) of the phosphate rock according to the following reaction? $$ \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}(s)+3 \mathrm{H}_{2} \mathrm{SO}_{4}(a q) \longrightarrow 3 \mathrm{CaSO}_{4}(s)+2 \mathrm{H}_{3} \mathrm{PO}_{4}(a q) $$

According to an analysis, a sample of phosphate rock contains \(71.2 \% \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}\), by mass. How many grams of calcium dihydrogen phosphate, \(\mathrm{Ca}\left(\mathrm{H}_{2} \mathrm{PO}_{4}\right)_{2}\), can be obtained from \(10.0 \mathrm{~g}\) of phosphate rock from the following reaction? $$ \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}(s)+4 \mathrm{H}_{3} \mathrm{PO}_{4}(a q) \longrightarrow 3 \mathrm{Ca}\left(\mathrm{H}_{2} \mathrm{PO}_{4}\right)_{2}(a q) $$

Write an equation for each of the following. a. burning of lithium metal in oxygen b. burning of methylamine, \(\mathrm{CH}_{3} \mathrm{NH}_{2}\), in excess oxygen (N ends up as \(\mathrm{N}_{2}\) ) c. burning of diethyl sulfide, \(\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{~S}\), in excess oxygen

Write an equation for each of the following. a. burning of calcium metal in oxygen b. burning of phosphine, \(\mathrm{PH}_{3}\), in excess oxygen c. burning of ethanolamine, \(\mathrm{HOCH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}\), in excess oxygen (N ends up as \(\mathrm{N}_{2}\) )

What are the oxidation numbers of sulfur in each of the following? a. \(\mathrm{SF}_{6}\) b. \(\mathrm{SO}_{3}\) c. \(\mathrm{H}_{2} \mathrm{~S}\) d. \(\mathrm{CaSO}_{3}\)

What are the oxidation numbers of sulfur in each of the following? a. \(\mathrm{S}_{8}\) b. \(\mathrm{CaS}\) c. \(\mathrm{CaSO}_{4}\) d. \(\mathrm{SCl}_{4}\)