Chapter 10 Question Set
1. (a) State the four principle types of bonding in crystalline solids and give examples of
each. (b) what is the fundamental physical origin of all of them? (c) What kind of
particle is presenting the crystal structure of each of them?
Answer:
(a) Ionic: NaCl; Covalent: diamond; van der Waals: ice; metallic: copper
(b) In each case, the bonding is due to electric forces
(c) Ions; atoms, molecules, ions
8. Solids of which type have the lowest melting points? Solids of which type are the best
conductors of heat and electric current?
Answer:
Molecular solids have the lowest melting point as the have the lowest energy bonding (van
der Walls forces) holding them together. Metals are the best conductors of heat and electric
current.
11. Why do bubbles of gas form in a glass of soda water when it warms up?
Answer:
Gases such as CO2 dissolve better in cold water than they do in warm water. So dissolved
CO2 in soda water comes out of solution as a gas bubble on the side of the glass as it warms.
13. What is the difference between a molecular ion and a polar molecule?
Answer:
A molecular ion is a molecule that has gained or lost an electron and so carries a charge. A
polar molecule is one that still has all of its electrons but they are unevenly distributed around
the molecule making it polar.
18. The pesticide DDT concentrates in the fat of animals and tends to remain in the soil
despite heavy rain that washes away other contaminants. What do these observations tell
you about the nature of the DDT molecule?
Answer:
These observations tell us that DDT is a very non-ionic, non-polar molecule.
23. Which is more strongly acidic, a solution of pH 3 or one of pH 5? Which is more strongly
basic, a solution of pH 8 or one of pH 10?
Answer:
The pH 3 solution is more strongly acidic than the pH 5 solution. The pH10 solution is more
strongly basic than the pH 8 solution.
26. Which of the following are weak acids? Hydrochloric acid, nitric acid, acetic acid, sulfuric
acid, citric acid?
Answer:
Acetic acid and citric acid are both weak acids compared to hydrochloric, nitric and sulfuric
acids.