Chapter 12
Liquids: Condensation, Evaporation, and Dynamic Equilibrium
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ver the past weeks, you have seen numerous examples of how chemistry can deepen your understanding of everyday phenomena. In this chapter, we revisit the topic of liquids and the changes they undergo, in order to explain some of the things you might experience on an unusually warm spring morning.
7:47 a.m. You get out of bed and take a quick shower. As you step out of the shower, you shiver with cold, even though the day is already warm.
7:51 a.m. You turn toward the bathroom mirror to comb your hair, but it’s so steamed up you can hardly see yourself. What causes water to collect on the mirror’s surface?
7:54 a.m. The water that dripped onto the floor has almost dried up now, but the water that collects in the bottom of your toothbrush cup never seems to disappear. Why?
8:01 a.m. Drops of cologne land on the counter. Why do they evaporate so much more quickly than water, and even more quickly in the heat from your blow dryer?
8:03 a.m. You notice a can of hair spray sitting on the window ledge in the hot sun. You’ve heard that if its temperature gets high enough, the can will explode. What causes that to happen?
8:04 a.m. Heating the water for your morning tea, you wonder what causes bubbles to form when the water boils—and why they don’t form until the water becomes extremely hot. That reminds you—why did it take so long to boil the potatoes during your backpacking trip to the high Sierras last week?
8:12 a.m. Whew! That’s a lot of wondering for the first few minutes of your day. Why not relax, drink your tea, and settle down to read this chapter? All of your questions are about to be answered.
Why does water vapor condense on a bathroom mirror?
12.1 Changing from Gas to Liquid and from Liquid to Gas—An Introduction to Dynamic Equilibrium
12.2 Boiling Liquids
12.3 Particle-Particle Attractions
Describe the relationship between the temperature of a substance and the motion of its component particles. (Section 3.1.)
Compare the freedom of motion and the attractions between the component particles in solids, liquids, and gases. (Section 3.1.)
Given a formula for a compound, classify it as either a molecular compound or an ionic compound. (Section 5.2.)
Given the names or formulas for two elements, decide whether the bond that would form between them would be covalent or ionic. (Section 5.2.)
Given the formula for a molecule or polyatomic ion, draw a reasonable Lewis structure for it. (Section 5.5.)
Given the Lewis structure or enough information to produce it, draw the geometric sketch of a molecule, including bond angles. (Section 5.7.)
Given a name or chemical formula, tell whether it represents a binary ionic compound, an ionic compound with polyatomic ion(s), a binary covalent compound, a binary acid, or an oxyacid. (Section 6.5.)
Convert between names and chemical formulas for binary ionic compounds, ionic compounds with polyatomic ion(s), binary covalent compounds, binary acids, and oxyacids. (Section 6.5.)
Review Skills
The presentation of information in this chapter assumes that you can already perform the tasks listed below. You can test your readiness to proceed by answering the Review Questions at the end of the chapter. This might also be a good time to read the Chapter Objectives, which precede the Review Questions.
