Complete and balance the following chemical equations: (a) hardening of plaster containing slaked lime

$$\mathrm{Ca}(\mathrm{OH})_2+\mathrm{CO}_2 \longrightarrow$$

(b) removal of sulfur dioxide from the flue gas of power plants

$$\mathrm{CaO}+\mathrm{SO}_2 \longrightarrow$$

(c) the reaction of baking powder that produces carbon dioxide gas and causes bread to rise

$$\mathrm{NaHCO}_3+\mathrm{NaH}_2 \mathrm{PO}_4 \longrightarrow$$

In drawing Lewis structures, we learn that a hydrogen atom forms only one bond in a covalent compound. Why?

The reaction of calcium hydride, $\mathrm{CaH}_2$, with water can be characterized as a Lewis acid-base reaction: $\mathrm{CaH}_2(s)+2 \mathrm{H}_2 \mathrm{O}(l) \longrightarrow \mathrm{Ca}(\mathrm{OH})_2(a q)+2 \mathrm{H}_2(\mathrm{~s})$ Identify the Lewis acid and the Lewis base among the reactants. The reaction is also an oxidation-reduction reaction. Identify the oxidizing agent, the reducing agent, and the changes in oxidation number that occur in the reaction.

Why does hydrogen not exhibit an oxidation state of 1 - when bonded to nonmetals?

Why does white phosphorus consist of tetrahedral $\mathrm{P}_4$ molecules while nitrogen consists of diatomic $\mathrm{N}_2$ molecules?

Sodium chloride and strontium chloride are both white solids. How could you distinguish one from the other?

Arrange the following in order of increasing electronegativity: $\mathrm{F} ; \mathrm{Cl} ; \mathrm{O}$; and $\mathrm{S}$.

Determine the oxidation state of sulfur in each of the following: (a) $\mathrm{SO}_3$ (b) $\mathrm{SO}_2$ (c) $\mathrm{SO}_3 2-$

Determine the oxidation number of each element in each of the following compounds: (a) $\mathrm{HCN}$ (b) $\mathrm{OF}_2$ (c) $\mathrm{AsCl}_3$

Write balanced chemical equations for the reaction of the following acid anhydrides with water: (a) $\mathrm{SO}_3$ (b) $\mathrm{N}_2 \mathrm{O}_3$ (c) $\mathrm{Cl}_2 \mathrm{O}_7$ (d) $\mathrm{P}_4 \mathrm{O}_{10}$ (e) $\mathrm{NO}_2$

Nitrogen in the atmosphere exists as very stable diatomic molecules. Why does phosphorus form less stable $\mathrm{P}_4$ molecules instead of $\mathrm{P}_2$ molecules?

Carbon forms a number of allotropes, two of which are graphite and diamond. Silicon has a diamond structure. Why is there no allotrope of silicon with a graphite structure?

Suppose you discovered a diamond completely encased in a silicate rock. How would you chemically free the diamond without harming it?

A hydride of silicon prepared by the reaction of $\mathrm{Mg} 2 \mathrm{Si}$ with acid exerted a pressure of 306 torr at $26^{\circ} \mathrm{C}$ in a bulb with a volume of $57.0 \mathrm{~mL}$. If the mass of the hydride was $0.0861 \mathrm{~g}$, what is its molecular mass? What is the molecular formula for the hydride?