Untitled - Kelly Walsh High School

Aqueous Solutions 75
The calculation in this problem begins like the second example in this section:
(0.0400 L)a 0.100 mol HC2H3O2 ba
L
1 mol Ca(OH) 2
b
2 mol HC2H3O2 These steps give us the moles of calcium hydroxide. To get the molarity of calcium
hydroxide, we use the definition of molarity, which tells us we need to
divide these moles by the volume, in liters, of the calcium hydroxide solution.
In order to finish the problem, we must add one more step:
(0.0400 L)a 0.100 mol HC2H3O2 ba
L
1 mol Ca(OH) 2 1
ba
2 mol HC2H3O2 0.0250 L b
0.0800 M Ca(OH) 2
This calculation leaves us with the appropriate number of significant figures and
the correct units.
It is possible to expand these examples to any titration problem, acid-base,
redox, precipitation, and so on. Just remember that the key is the mole concept.
In this chapter, you learned about solutions and how to use molarity to express
the concentration of solutions. You also learned about electrolytes and nonelectrolytes.
Using a set of solubility rules allows you to predict whether or not
precipitation will occur if two solutions are mixed. You examined the properties
of acids and bases and the neutralization reactions that occur between them.
You then learned about redox reactions and how to use an activity table to predict
redox reactions. You learned about writing net ionic equations. Finally, you
learned how to use the technique of titrations to determine the concentration
of an acid or base solution.
1. True/False. A solution is a heterogeneous mixture.
2. True/False. Acids are electrolytes.
3. Which of the following is a molecular compound?
a. NaCl b. KNO 3 c. CH 3OH d. CsOH e. (NH 4) 2SO 4
4. Which of the following is not soluble in water?
a. AgCl b. KCl c. NH 4Cl d. FeCl 2 e. FeCl 3
5. Which of the following is insoluble in water?
a. (NH 4) 2SO 4 b. Na 2SO 4 c. MgSO 4 d. ZnSO 4 e. BaSO 4
6. You are to mix two aqueous solutions to see if a precipitate will form.
Which of the following combinations will not form a precipitate?
a. AgNO 3 KBr b. Pb(NO 3) 2 KCl c. NaOH FeCl 2
d. Na 3PO 4 NH 4Cl e. CaCl 2 K 2SO 4