Ch. 7 Review and Assessment Answer Key
Organizing Information
a. Solvents
b. Ions
c. Do not conduct
Reviewing Key Terms
1.b
2.b
3.c
4. a
5.c
6.b
Checking Concepts
7. You could shine a flashlight through them. Light passes through a solution without scattering, but a
colloid scatters the light.
8. A concentrated solution of sugar water contains more solute relative to the amount of solvent than a
dilute solution. A concentrated solution tastes sweeter and has a lower freezing point and high boiling
point.
9. Tomato juice would turn blue litmus paper red, and it would react with a base such as baking soda.
10. An indicator is a different color in an acid that it is in a base.
11. A strong base might have a pH of 14, 13, or 12.
12. HCl and NaOH combine to make the salt NaCl.
Thinking Critically
13. As divers descend deeper under water, more nitrogen in the air dissolves in their blood because
pressure increases with depth. If divers return too quickly gas comes out of solution, blocks blood flow,
and causes severe pain called “the bends”.
14. The solubility of gas is lower at higher temperatures. Heating reduces the solubility of dissolved
gases in water and it causes some of the gases to come out of the solution.
15. Based on litmus paper changes, one liquid is an acid and the other is a base. When they react
together they form a neutral substance - salt and water. This is known as neutralization.
16. An acid forms hydrogen ions (H+) in a water solution. A base forms hydroxide ions (OH-) in a water
solution.
Math Practice
17. KCl
18. Too much antacid can cause the pH in the stomach so that it is too high and will not allow the
enzyme, pepsin, to work well on proteins.
19. 100g
20. 50 ml
Applying Skills
21. You can tell that the solution contains a weak acid because very few acid particles have broken up
into hydrogen ions and negative ions.
22. The unpaired yellow cubes and the unpaired blue circles represent ions.
23. Your diagram should show that most of the particles of the strong acid have broken up into
hydrogen ions and negative ions.
24. Hydrogen ion concentration is measure by pH. The higher the concentration, the lower the pH. A
strong acid produces more hydrogen ions in solution, so it has a lower pH than a weak acid of the same
concentration.