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(a) State the four principal types of bonding in crystalline solids and give an example of each. (b) What is the fundamental physical origin of all of them? (c) What kind of particle is present in the crystal structure of each of them? |
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Lithium atoms, like hydrogen atoms, have only one electron in their outer shells, yet lithium atoms do not join together to form Li2 molecules the way hydrogen atoms form H2 molecules. Instead, lithium is a metal with each atom part of a crystal structure. What do you think is the reason for the difference? |
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3 | |
How could you tell experimentally whether a fragment of a clear, colorless material is glass or a crystalline solid? |
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4 | |
What kind of solid contains a "gas" of freely moving electrons? Does this gas include all the electrons present? |
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5 | |
Van der Waals forces are strong enough to hold inert gas atoms together to form liquids at low temperatures, but these forces do not lead to inert gas molecules at higher temperatures. Why not? |
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6 | |
What ions would you expect to find in the crystal structures of MgO and K2S? |
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7 | |
What ions would you expect to find in the crystal structures of CaF2 and KI? |
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8 | |
Solids of which type have the lowest melting points? Solids of which type are the best conductors of heat and electric current? |
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9 | |
Give two ways to tell whether a sugar solution is saturated or not. |
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10 | |
Why is the solubility of one gas in another unlimited? |
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11 | |
Why do bubbles of gas form in a glass of soda water when it warms up? |
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12 | |
Ordinary tap water tastes different after it has been boiled. Can you think of the reason why? |
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13 | |
What is the difference between a molecular ion and a polar molecule? |
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14 | |
Seawater freezes at a lower temperature than pure water because of the salts dissolved in it. How does the boiling point of seawater compare with that of pure water? |
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15 | |
How could you distinguish experimentally between an electrolyte and a nonelectrolyte? |
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16 | |
The ions of potassium (K) and calcium (Ca) both contain 18 electrons. Would you expect the chemical behaviors of these elements to be similar? |
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17 | |
Name one property by which you could distinguish (a) Cl- from NO3-, (b) Ag+ from Na+, (c) Cu2+ from Ca 2+. |
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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? |
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19 | |
With the help of Fig. 10-13 predict what will happen when a concentrated solution of sodium nitrate at 50°C is added to a saturated solution of potassium chloride at the same temperature. |
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20 | |
At 10°C, which is more concentrated, a saturated solution of potassium nitrate or a saturated solution of potassium chloride? At 60°C? |
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21 | |
Do pure acids in the liquid state contain H+ ions? If not, what do such acids consist of? |
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22 | |
Is it correct to say that the only ions an acidic solution contains are H+ ions and that the only ions a basic solution contains are OH- ions? If not, what would correct descriptions of such solutions be? |
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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? |
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24 | |
In an acidic solution, why is the OH- concentration lower than it is in pure water? |
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25 | |
Justify the statement that water is both a weak acid and a weak base. |
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26 | |
Which of the following are weak acids? Hydrochloric acid, nitric acid, acetic acid, sulfuric acid, citric acid. |
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27 | |
Would you expect HBr to be a weak or strong acid? Why? |
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28 | |
When a salt that contains the negative ion of a weak acid is dissolved in water, the solution is basic. For example, a solution of sodium acetate (the corresponding acid is acetic acid) is basic. Why? |
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