Name:______________________________
Hour: ________________
Chapter 4: Aqueous Reactions and Solution Stoichiometry
Reading Guide: Section 4.1: General Properties of Aqueous Solutions (Pg 122)
1. A _____________________ is a homogeneous mixture of two or more substances.
2. The substance present in greatest quantity is usually called the __________________.
3. The other substances in the solution are known as the __________________; they are said to be
dissolved in the solvent.
Electrolytic Properties
4. What is one way that a solution of salt water and a solution of sugar water are different?
_______________________________. The salt solution is a good conductor of
________________, whereas the sugar solution is not.
5. Although water itself is a poor conductor of electricity, the presence of ___________________
causes aqueous solutions to become good conductors.
6. ______________ carry electrical charge from one electrode to the other, completing the
electrical circuit.
7. Thus, the conductivity of ___________ solutions indicates the presence of ions in the solution,
and the lack of conductivity of __________________ solutions indicates the absence of ions in
solution.
8. When NaCl dissolves in water, the solution contains __________ and _________ ions, each
surrounded by water molecules.
9. When sucrose dissolves in water, the solution contains only ______________ sucrose molecules
surrounded by water.
10. A substance whose aqueous solutions contain ions is called an ___________________.
11. A substance that does not form ions in solution is called al _____________________.
12. The difference between NaCl and C12H22O11 arises largely because NaCl is _________________
and C12H22O11 is _________________.
Ionic Compounds in Water
13. The ionic solid _______________ into its component ions as it dissolves.
14. Water is a very effective ___________________ for ionic compounds.
15. Although water is electrically neutral molecule, one end of the molecule is rich in
_______________ and thus possesses a partial __________________ charge, denoted by
__________.
16. The other end has a partial ______________ charge, denoted by ______________.
17. Positive ions called _______________ are attracted to the negative end of water, and negative
ions called ______________ are attracted by the positive end.
18. Draw the water molecule diagram shown on the right margin (under the figure 4.2, to the right
of the text) showing the partial negative and partial positive regions of water:
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19. As an ionic compound ____________, the ions become surrounded by water molecules. The
ions are said to be __________________.
20. The _________________ process helps stabilize the ions in solution and prevents _________
and ___________________ from recombining.
21. Furthermore, because the ions and their shells of surrounding water molecules are free to move
about, the ions become _________________ uniformly throughout the solution.
22. We can usually predict the nature of the ions present in a solution of an ionic compound from
the ___________________ _____________ of the substance.
23. Sodium sulfate ( __________________), for example, dissociates into ____________ ions
(___________) and _______________ ions (_________________).
24. You must remember the ___________________ and ________________ of common ions to
understand the forms in which ionic compounds exist in aqueous solution.
25. Give it some thought: What dissolved species are present in a solution of
a. KCN
______________ and _____________ ions
b. NaClO4
______________ and ______________ ions
Molecular Compounds in Water
26. When a molecular compound dissolves in water, the solution usually consists of ___________
________________ dispersed throughout the solution.
27. Consequently, most molecular compounds are _____________________.
28. There are, however, a few molecular substances whose aqueous solutions contain
______________.
29. The most important of these are ___________________.
30. For example, when HCl (g) dissolves in water to form hydrochloric acid, HCl (aq), it
_____________________; that is, it dissociates into _________ and ______________ ions.
Strong and Weak Electrolytes
31. There are two categories of electrolytes, _________________ and ________________, which
differ in the extent to which they conduct electricity.
32. ____________________ _____________________ are those solutes that exist in solution
completely or nearly completely as ions.
33. Essentially all soluble ______________________ ________________ and a few molecular
compounds (such as __________________) are strong electrolytes.
34. __________________ _______________ are those solutes that exist in solution mostly in the
form of molecules with only a small fraction in the form of ions.
35. For example, in a solution of __________________ ________________ (______________) most
of the solute is present as _________________ molecules.
36. Only a small fraction (about _____________) of the ___________________ is present as
______________ and __________________ ions.
37. We must be careful not to confuse the extent to which an electrolyte _____________________
as either strong or weak.
38. For example, _____________________ is extremely soluble in water but is a weak electrolyte.
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39. _______________________, on the other hand, is not very soluble, but the amount of the
substance that does dissolve dissociates almost _____________________, so ____________ is a
strong electrolyte.
40. When a weak electrolyte such as acetic acid ionizes in solution, we write the reaction in the
following manner: ____________________________________________________________.
41. The double arrow means that the reaction is significant in _____________ directions.
42. At any given moment some _______________________ molecules are ionizing to form
_________ and ________________. At the same time, _____________ and ______________
ions are recombining to form ____________________.
43. The balance between these opposing processes determines the relative number of
______________ and neutral ____________________.
44. This balance produces a state of _________________ __________________ that varies from
one weak electrolyte to another.
45. Chemists use a ________________ ______________ to represent the ionization of weak
electrolytes and a ________________ _______________ to represent the ionization of strong
electrolytes.
46. Because HCl is a strong electrolyte, we write the equation for the ionization of HCl as follows:
___________________________________________.
47. The absence of a reverse arrow indicates that the __________ and _____________ ions have no
tendency to _____________ and form HCl molecules.
48. In the sections ahead we will begin to look more closely at how we can use the composition of a
compound to predict whether it is a ____________ electrolyte, _______________ electrolyte,
or __________________ electrolyte.
49. For the moment, it is important only to remember that _________________
________________ __________________ are strong electrolytes.
50. We identify ionic compounds as being ones composed of ________________ and
__________________, or compounds containing the _______________ ion.
51. Give it some thought: Which solute will cause the light bulb in the experiment shown in Figure
4.2 to glow more brightly, CH3OH or MgBr2? ______________________
Sample Exercise 4.1 Relating Relative Numbers of Anions and Cations to Chemical Formulas
(Pg 125)
The diagram on the right represents an aqueous solution of one of the following compounds:
MgCl2, KCl, K2SO4. Which solution does it best represent and WHY?
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Draw diagrams (such as that above) representing aqueous solutions of each of the following ionic
compounds such that each contains 6 cations and the appropriate number of anions:
NiSO4
Ca(NO3)2
Na3PO4
Al2(SO4)3
Distributed Practice:
1. A strip of zinc metal having a mass of 2.00 g is placed in an aqueous solution containing 2.50 g
of silver nitrate.
a. Write the balanced chemical reaction:
b. Which reactant is the limiting reagent? Justify your answer with both a mathematical
calculation and using a sentence that explains your choice.
c. How many grams of Ag will form?
d. How many grams of the excess reactant will be left at the end of the reaction?
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