Breakdown, Discussion & Help With Sample Problems: What You Should Know

12.1 Types of Solutions: Intermolecular Forces and the Prediction of Solubility

Important terms in Section12.1 include solute, solvent, miscible, solubility, and hydration shells. Topics covered include intermolecular forces in solution and gaso and solid solutions.

Of import is the section (p 466) that deals with liquid solutions and the role of molecular polarity and hydrogen bonding in liquid solutions. FIg 12.3 (p 467) nicely describes the importance of hydrogen bonding in solute solvation in water solvent.

The CHEMICAL CONNECTIONS graphic on p 469 contains informative and highly readable information about how antibiotics work...a sensible inclusion in Chapter 12 because of their mechanism of action, which involves the antibiotic disrupting ion balance by forming a channel in the membrane through which aqueous ions can flow. Polarity is an important concept in the mechanisms of antibiotics as well.

12.2 Energy Changes in the Solution Process

Sub-sections within 12.2 include discussion of heats of solution and hydration, as well as the importance of entropy in the solution process.

Figs 12.9 and 12.10 (pp 474-5) are highly instructive as far as the enthalpis of solution are concerned for dissolving various compounds in water and in hexane.

12.3 Solubility as an Equilibrium Process

Important terms in Section 12.3 include saturated, unsaturated, and super-saturated.

Topics covered in 12.3 include the effects of temperature and pressure on solubility.

click here for a few words about SAMPLE PROBLEM 12.2 (page 477)

12.4 Quantitative Ways of Expressing Concentration

Molarity was introduced in Chapter 3 as a means for quantifying the concentrations of solutions. In Section 12.4, additional concentration parameters are discussed, including molality, parts by mass (mass percent), parts by volume (volume percent), and mole fraction.

click here for a few words about SAMPLE PROBLEM 12.4 (page 481)

click here for a few words about SAMPLE PROBLEM 12.5 (page 482)

click here for a few words about SAMPLE PROBLEM 12.6 (page 483)

12.5 Colligative Properties of Solutions

The colligative (collective) properties of solutions include vapor pressure lowring, boiling point  elevantion, freezing point depression, and osmotic pressure.

Colligative properties of solutions are the differences in the physical properties of solutions that are due solely to the number of solute particles within the solutions.

click here for a few words about SAMPLE PROBLEM 12.8 (page 490)

12.6 The Structure and Properties of Colloids

Colloids and suspensions are discussed in Section 12.6; the CHEMICAL CONNECTIONS graphic on pp 499-501 describes how water treatment plants take advantage of colloids.

exercises such as numbers 12.4, 12.23, 12.29, 12.38, 12.58, 12.62, and 12.93 are all straightforward problems of the type that are often found on CHEM 200 exams