AP Chemistry Practice Test 28

Questions 1-5 refer to the following information.

Questions refer to the titration curve below, which is of a weak base titrated with a strong acid.

Image

The pH was measured with a pH meter after small volumes of 0.125 M HCl were added to 25.0 mL of a weak base. Data from that experiment are shown in the above graph.

1. Which of the following describes the base that is being titrated?

2. Between which two points on the titration curve can the solution be described as a buffer?

3. For the best results with a visual indicator (one that changes color), what will optimize the results?

4. If the student uses a pH indicator that changes color from pH 6 to 8, which statement best characterizes the expected observations?

5. Which arrow points to the place on the curve where pH = pKaof the conjugate acid of the base?

6.

In the diagram above, which labeled arrow is pointing toward a covalent bond and which is pointing toward a hydrogen bond?

Covalent Bond   Hydrogen Bond

7. Which would be the easiest way to burn a copper penny?

8. S(s) + O2(g) → SO2(g)

The equation for the reaction between sulfur and oxygen, written in equation form above, can be interpreted in all of the following ways except

9.

Morphine, C17H19NO3 (shown above), has a Kb = 8.0 × 10-7. If a 0.00100 M solution of morphine is prepared, the expected pH will be in which one of the following pH ranges?

10. What is the pKa of morphine hydrochloride, C17H20NO3+Cl-, where C17H20NO3+ is the conjugate acid of the morphine in the previous question?