Study Guide for Exam Chem 112, latest 2022

Study Guide for Exam
Chem 112, latest 2022

There are 70 problems here, most are pretty easy, and a few are very hard. Remember they
represent examples of what might be on the final. The problems on the final will be close
variations on some of these themes, and there will be about 20 or so problems on the exam.
The best way to use this is to work each problem, and then make sure you know why the answer
is the correct one. Come to the CIC if you have any questions!

Chapter 17

1) An important buffer in the blood is a mixture of
A) sodium chloride and hydrochloric acid.
B) hydrochloric acid and sodium hydroxide.
C) carbonic acid and bicarbonate ion.
D) acetic acid and bicarbonate ion.
E) acetic acid and carbonate ion.

2) Identify a good buffer.
A) small amounts of both a weak acid and its conjugate base
B) significant amounts of both a strong acid and a strong base
C) small amounts of both a strong acid and a strong base
D) significant amounts of both a weak acid and a strong acid
E) significant amounts of both a weak acid and its conjugate base

3) Define buffer capacity.
A) Buffer capacity is the amount of acid or base that can be added to a buffer without
destroying its effectiveness.
B) Buffer capacity is the amount of acid that can be added until all of the base is used up.
C) Buffer capacity is the amount of base that can be added until all of the acid is used up.
D) Buffer capacity is the amount of acid that can be added until all of the acid is used up.
E) Buffer capacity is the amount of base that can be added until all of the base is used up.

4) Which of the following is true?
A) The equivalence point is where the amount of acid equals the amount of base during any
acid-base titration.
B) At the equivalence point, the pH is always 7.
C) An indicator is not pH sensitive.
D) A titration curve is a plot of pH vs. the [base]/[acid] ratio.
E) None of the above are true.

5) When titrating a strong monoprotic acid with KOH at 25°C, the
A) pH will be less than 7 at the equivalence point.
B) pH will be greater than 7 at the equivalence point.
C) titration will require more moles of base than acid to reach the equivalence point.
D) pH will be equal to 7 at the equivalence point.
E) titration will require more moles of acid than base to reach the equivalence point.

, 6) When titrating a weak monoprotic acid with NaOH at 25°C, the
A) pH will be less than 7 at the equivalence point.
B) pH will be equal to 7 at the equivalence point.
C) pH will be greater than 7 at the equivalence point.
D) titration will require more moles of base than acid to reach the equivalence point.
E) titration will require more moles of acid than base to reach the equivalence point.

7) When titrating a monoprotic strong acid with a weak base at 25°C, the
A) pH will be 7 at the equivalence point.
B) pH will be greater than 7 at the equivalence point.
C) titration will require more moles of the base than acid to reach the equivalence point.
D) titration will require more moles of acid than base to reach the equivalence point.
E) pH will be less than 7 at the equivalence point.

8) If the pKa of HCHO2 is 3.74 and the pH of an HCHO2/NaCHO2 solution is 3.89, which of
the following is true?
A) [HCHO2] < [NaCHO2]
B) [HCHO2] = [NaCHO2]
C) [HCHO2] > [NaCHO2]
D) [HCHO2] >> [NaCHO2]
E) It is not possible to make a buffer of this pH from HCHO2 and NaCHO2.

9) If the pKa of HCHO2 is 3.74 and the pH of an HCHO2/NaCHO2 solution is 3.11, which of
the following is true?
A) [HCHO2] < [NaCHO2]
B) [HCHO2] = [NaCHO2]
C) [HCHO2] << [NaCHO2]
D) [HCHO2] > [NaCHO2]
E) It is not possible to make a buffer of this pH from HCHO2 and NaCHO2.

10) If the pKa of HCHO2 is 3.74 and the pH of an HCHO2/NaCHO2 solution is 3.74, which of
the following is true?
A) [HCHO2] > [NaCHO2]
B) [HCHO2] = [NaCHO2]
C) [HCHO2] < [NaCHO2]
D) [HCHO2] < <[NaCHO2]
E) It is not possible to make a buffer of this pH from HCHO2 and NaCHO2.

11) Give the equation for an unsaturated solution in comparing Q with Ksp.
A) Q > Ksp
B) Q < Ksp
C) Q = Ksp