NAME _______________________ CHEM 142
April 23, 2008 Exam 4
Please write your name at the top of each page of this examination in the space provided. I
will deduct 5 points from your score if you do not do so!
Section A. MULTIPLE CHOICE QUESTIONS: (5 pts each)
Choose the best answer. Clearly circle your answer. No credit will be given if more than
answer is marked or if there is any ambiguity about what your answer is. Each question in
this section is worth 5 points. Zero points are given for incorrect answers: therefore, it is to
your advantage to give an answer for each question.
1. Which of the following is the strongest acid? [This is not a trick question.]
a. HNO3b. H2S c. PH3d. SiH4 e. CH4
2. Will a precipitate be formed if 0.100 mol of Ag+ and 0.001 mol of SO42- are added to
water to make 1.0 L of solution? (Ksp = 1.4 x 10-5)
a. Yes, because Q > Ksp
b. Yes, because Q < Ksp
c. No, because Q > Ksp
d. No, because Q < Ksp
3. Which of the following describes what happens to the solubility of a slightly soluble
ionic compound when a common ion is added to a saturated solution of the compound?
a. The solubility of the ionic compound is reduced.
b. The solubility of the ionic compound is increased.
c. There is no effect on the solubility of the ionic compound.
d. More of the ionic compound dissolves.
4. What is the smallest [Ag+] that would cause the precipitation of Ag2CrO4 from 0.050 M
Na2CrO4 (aq)? (the Ksp of Ag2CrO4 is 2.4 x 10-12)
a. 4.8 x 10-11 M
b. 6.9 x 10-6 M
c. 1.5 x 10-6 M
d. 8.4 x 10-5 M
e. 2.4 x 10-11 M
5. Identify the acid and base on each side of the following equation:
