Fireworks are an extraordinary display of chemical reactions. Fig. 8-CO, p. 161

p. 163

Fig. 8-1, p. 166 Figure 8.1: One-mole quantities of some elements. The cylinders (left to right) hold mercury (201 g), lead (207 g), and copper (64 g). The two Erlenmeyer flasks hold sulfur (left, 32 g) and magnesium (right, 24 g). All rest on 1 mole of aluminum in the form of foil (27 g) and also on the watch glass. Fig. 8-1, p. 166

The Personal Side: Amadeo Avogadro (1776–1856)

Decomposition of ammonium nitrate (NH4NO3); a reaction that is very fast.

Reaction of zinc (Zn) with hydrochloric acid to produce hydrogen gas; a reaction that is slower than the decomposition of ammonium nitrate. p. 169

Fig. 8-2, p. 170 Figure 8.2: Collisions and chemical reactions. Some collisions are successful and some are not. The difference is determined to a great extent by the kinetic energy of the particles. Fig. 8-2, p. 170

Fig. 8-2a, p. 170 Figure 8.2: Collisions and chemical reactions. Some collisions are successful and some are not. The difference is determined to a great extent by the kinetic energy of the particles. Fig. 8-2a, p. 170

Fig. 8-2b, p. 170 Figure 8.2: Collisions and chemical reactions. Some collisions are successful and some are not. The difference is determined to a great extent by the kinetic energy of the particles. Fig. 8-2b, p. 170

Figure 8.3: Energy profiles of two exergonic chemical reactions. Exergonic reactions are “downhill” processes overall in terms of energy, and the product is favored at equilibrium. Reaction (a) is faster than reaction (b) because the activation energy barrier (Eact) is lower for (a) than for (b). Fig. 8-3, p. 170

Figure 8.3: Energy profiles of two exergonic chemical reactions. Exergonic reactions are “downhill” processes overall in terms of energy, and the product is favored at equilibrium. Reaction (a) is faster than reaction (b) because the activation energy barrier (Eact) is lower for (a) than for (b). Fig. 8-3a, p. 170

Figure 8.3: Energy profiles of two exergonic chemical reactions. Exergonic reactions are “downhill” processes overall in terms of energy, and the product is favored at equilibrium. Reaction (a) is faster than reaction (b) because the activation energy barrier (Eact) is lower for (a) than for (b). Fig. 8-3b, p. 170

Fig. 8-4, p. 171 Figure 8.4: Temperature and reaction rate. When a light stick is bent, an inner glass tube breaks, allowing reactants to mix. The result is a chemical reaction that releases energy as light. You can see by the dimmer light in the ice water (right) that the colder temperature slows down the reaction. Fig. 8-4, p. 171

Reaction of chalk (calcium carbonate) with dilute hydrochloric acid. Left: Powdered blackboard chalk reacts faster because the greater surface area increases the amount in contact with the hydrochloric acid. Right: The reaction of a piece of blackboard chalk is slower than the reaction of powdered chalk. p. 171

p. 172 An alligator crossing a highway. Alligators are cold-blooded animals—the rate of their metabolism depends on the temperature. This alligator crawled onto a major highway during an evening when there was a sharp temperature drop. The resulting slow-down in reaction rate put him to sleep in the middle of the road, where considerate police directed traffic around him. Finally, at midday the temperature rose and he walked off without any coaxing. p. 172

Figure 8.5: Catalyzed decomposition of hydrogen peroxide [2 H2O2(aq) → 2 H2O(ℓ) + O2(g)] on a fresh piece of liver. The liver is well supplied with an enzyme for this reaction. Fig. 8-5, p. 172

Fig. 8-6, p. 172 Figure 8.6: Effect of a catalyst. All a catalyst does is lower the activation energy. Because more reactants have enough energy to overcome the reaction energy barrier, the reaction rate increases. Fig. 8-6, p. 172

Fig. 8-7, p. 173 Figure 8.7: A system at equilibrium. Water has reached equilibrium with its vapor in this ecosphere. Equilibrium also has been reached by the food and waste products of the inhabitants—a carefully balanced community of plants, shrimp, and a hundred or so kinds of microorganisms. Fig. 8-7, p. 173

Fig. 8-8, p. 174 Figure 8.8: Ammonia synthesis. In a demonstration of Le Chatelier’s principle, pressure shifts equilibrium of reaction with different amounts of gaseous reactants and products. Higher pressure shifts the reaction toward smaller amounts and therefore smaller volumes, of gas. To increase the amounts of ammonia produced, the synthesis is done under pressure. Fig. 8-8, p. 174

Fig. 8-9, p. 176 Figure 8.9: A favorable exergonic reaction. The favorable driving forces combine to make the reaction of sodium with water dramatically exergonic. Fig. 8-9, p. 176

Fig. 8-10a, p. 176 Figure 8.10: A favorable but endothermic reaction. The reaction of barium hydroxide and ammonium thiocyanate is one of the uncommon examples of a favorable reaction that absorbs heat from its surroundings. Fig. 8-10a, p. 176

Fig. 8-10b, p. 176 Figure 8.10: A favorable but endothermic reaction. The reaction of barium hydroxide and ammonium thiocyanate is one of the uncommon examples of a favorable reaction that absorbs heat from its surroundings. Fig. 8-10b, p. 176

Figure 8.11: Energy profile of an endergonic reaction. Endergonic reactions are “uphill” processes in terms of energy, and the reactant is favored at equilibrium. Fig. 8-11, p. 177

Natural processes that increase entropy.

Table 8-1, p. 178

p. 178 Visualizing body heat. Thermogram photos show heat in reds and yellow, illustrating that the body heats up with exercise. p. 178

How many of these items could have been repaired or manufactured to last longer?

Figure 8.12: Stages in the production, use, and disposal of manufactured products. At each stage energy is used; there is a possibility of air or water pollution; and there is generation of waste. Therefore, there is also the possibility for conservation and recycling at each stage. Fig. 8-12, p. 180

The World of Chemistry: Green Design p. 180