The AP Chemistry Test
2021 Test Changes
Updates from The AP College Board July 2019 have stated that the test format will be as follows:
| Section 1: Multiple Choice | Section 2: Free Response | ||||||||
| 60 Questions | 1 Hour 30 minutes | 50% of Exam Score | 7 Questions | 1 Hour 45 Minutes | 50% of Exam Score | ||||||||
|
A scientific or graphing calculator is recommended for use on Section 2. |
2020 Test Changes (Online)
Updates from The AP College Board March 2019 have stated that the test format will be as follows: The exam is 45 minutes long on-line and includes both a 20question multiple-choice section and a 2 question free-response section. The multiple-choice section accounts for half of each student's exam grade, and the free-response section counts for the other half.
You’ll have 45-minutes to take the exam online and it will only cover units 1-7. If you have already studied content from unit 8 or 9 don’t stress! It’s all worth knowing.
 | Two Long FRQs: Q1 = 25 minutes and will be 60% of your score, Q2 = 15 mins and will be 40% of your score |
| Make sure to print or open the Periodic Table of Elements and the AP Chemistry Equations and Physical Constants sheet |
| Calculators are allowed, but all calculations can be done without one |
2015 Test Changes
Updates from The AP College Board August 2015 have stated that the test format will be as follows: The exam is 3 hours and 15 minutes long and includes both a 90-minute multiple-choice section and a 105-minute free-response section. The multiple-choice section accounts for half of each student's exam grade, and the free-response section counts for the other half.
| Section | Question Type | Number of Questions | Timing |
| I | Multiple-Choice | 60 | 90 minutes |
| II
|
Long Free-Response | 3 ten point questions | 105 minutes |
| Short Free-Response | 4 four point questions |
2013 Test Changes
Updates from The AP College Board August 2013 have stated that the test format will be as follows: The exam is 3 hours long and includes both a 90-minute multiple-choice section and a 90-minute free-response section. The multiple-choice section accounts for half of each student's exam grade, and the free-response section counts for the other half.
| Section | Question Type | Number of Questions | Timing |
| I | Multiple-Choice | 60 | 90 minutes |
| IIa IIb |
Long Free-Response | 3 | 90 minutes |
| Short Free-Response | 4 |
2010 Test Changes
Updates from The AP College Board August 2010 have stated that the grading policy for Section I will no longer be determined by the (1/4) points attempted and missed rule.
2007 Test Changes
As described in
the new 2007, 2008 AP Chemistry Course Description, the AP Chemistry Exam will
have a new format beginning in May 2007. It is important to note that the
content covered by the exam will not change. The weighting of the two
major parts of the exam will change slightly -- Sections I and II will each
contribute 50 percent toward the final grade.
Section I (90 minutes) will not change and will still consist of 75
multiple-choice questions with broad coverage of chemistry topics. However,
there will be three primary changes in the format of Section II of the 2007
exam. While these changes do not introduce new content, students should be made
aware of these changes before taking the exam in May 2007.
The first change in Section II is that students will no longer be asked to
choose between alternative questions. All students will do the same six
questions: three problems, the first of which is an equilibrium problem;
question 4 (reactions); and two essay questions.
A second change in Section II relates to question 4, which assesses students'
knowledge about chemical reactions. Currently students are asked to write
chemical equations for five of eight given sets of reactants. In the new
question 4 format, all students will write balanced chemical equations
for three different sets of reactants and will answer a short question about
each of the three reactions.
The third change in Section II relates to the timing of Part A (during which
calculators are permitted) and Part B (when no calculators are permitted). In
Part A, students will have 55 minutes to answer three problems; in Part B,
students will have 40 minutes to answer question 4 and questions 5 and 6, the
two essay questions.
The table below summarizes the difference between the 2006 and 2007 AP Chemistry
Exam Section II formats. Note that the laboratory question can now appear in
Part A.
Table 1: A Comparison
of the 2006 and 2007 AP Chemistry Exam Section II Formats
|
2006 Section II Format |
2007 Section II NEW Format |
||
|
Part A, 40 minutes |
% of Section Score |
Part A, 55 minutes |
% of Section Score |
|
· Equilibrium problem |
20% |
· Equilibrium problem |
20% |
|
· Other problem (choice) |
20% |
· Other problem* |
20% |
|
|
|
· Other problem* |
20% |
|
Part B, 50 minutes |
% of Section Score |
Part B, 40 minutes |
% of Section Score |
|
·
Reactions question |
15% |
· Reactions question (3 required) |
10% |
|
· Laboratory essay |
15% |
· Essay question* |
15% |
|
· Required essay |
15% |
· Essay question* |
15% |
|
· Other essay (choice) |
15% |
*One of the other problems or essays will be based on laboratory |
|
One area of interest among AP teachers lies in
the reformatting of question 4; therefore, the remainder of this article will
present the reactions that appeared in the 2006 exam and show how these
reactions might be recast in the new 2007 format.
The current directions for question 4 are as follows.
4. Write the formulas to show the reactants and the products for any FIVE of the laboratory situations described below. No more than five choices will be graded. In all cases, a reaction occurs. Assume that solutions are aqueous unless otherwise indicated. Represent substances in solution as ions if the substances are extensively ionized. Omit formulas for any ions or molecules that are unchanged by the reaction. You need not balance the equations.
Example: A strip of magnesium is added to a solution of silver nitrate.
|
Ex. |
Mg + Ag+ → Mg2+ + Ag |
These instructions will be slightly modified in the 2007 exam booklet; the new
wording (added in boldface) will be very close to this:
4. For each of
the following three reactions, in part (i) write a BALANCED equation and in part
(ii) answer the question about the reaction. In part (i), coefficients should be
in terms of lowest whole numbers. Assume that solutions are aqueous unless
otherwise indicated. Represent substances in solutions as ions if the substances
are extensively ionized. Omit formulas for any ions or molecules that are
unchanged by the reaction.
Example: A strip of magnesium is added to a solution of silver nitrate.
(i) Mg + 2 Ag+ → Mg2+ + 2 Ag
(ii) Which substance is oxidized in the reaction?
Answer: Magnesium (Mg) metal
As shown, the new directions for question 4 require the students to provide a balanced chemical equation showing only the reacting substances and ask the student to answer a question about the reaction. The majority of the credit for a response will be earned for writing the balanced equation; the remaining credit will be earned for correctly answering the question that follows each reaction, which will require the student to focus more on the meaning of the reaction. For instance, the example given above is an oxidation-reduction reaction. Ask yourself what your students should know about a redox reaction. Here are some questions that I hope most students would be able to answer:
· Which substance is being oxidized?
· Which substance is being reduced?
· What is the change in the oxidation number of the magnesium?
· What would you observe happening to the magnesium metal strip in this reaction?
Any one of
these questions -- and you may be able to come up with more -- is representative
of what question 4 will include on the 2007 AP Chemistry Exam. Table 2 (below)
lists some sample questions -- suggested by members of the AP Chemistry
Development Committee -- that might be asked about the reactions that appeared
on the 2006 exam. Part (i) asks for the balanced chemical equation, omitting any
ions or molecules that are unchanged in the reaction; part (ii) asks one
question that focuses on such things as the type of reaction (redox,
proton-transfer, Lewis acid-base, and so forth), the stoichiometry of the
reaction, and the physical observations that one might expect as the reaction
occurs.
Table 2: Question 4
Reactions on the 2006 AP Chemistry Exam Recast in the 2007 NEW Format
|
(a) Solid potassium chlorate is strongly heated and decomposes, resulting in a change in the oxidation numbers of both chlorine and oxygen. (i) 2 KClO3 → 2 KCl + 3 O2 |
(ii) What is the oxidation number of chlorine before and after the reaction? Answer: Chlorine has an oxidation number of +5 in KClO3 and -1 in KCl. |
|
(b) Solid silver chloride is added to a solution of concentrated hydrochloric acid, forming a complex ion. (i) AgCl + Cl− → [AgCl2]− |
(ii) Which species acts as a Lewis base in the reaction? Explain. Answer: The chloride ion acts as a Lewis base in the reaction because it donates an electron pair. |
|
(c) A solution of ethanoic (acetic) acid is added to a solution of barium hydroxide. (i) HC2H3O2 + OH− → H2O + C2H3O2− |
(ii) Explain why a mixture of equal volumes of equimolar solutions of ethanoic acid and barium hydroxide is basic. Answer: In the mixture there are initially twice as many moles of hydroxide ions as molecules of acid; since they react in a 1:1 ratio, there is an excess of hydroxide ions after the reaction is complete, leading to the basic solution. |
|
(d) Ammonia gas is bubbled into a solution of hydrofluoric acid. (i) NH3 + HF → NH4+ + F− |
(ii) Identify a conjugate acid-base pair in the reaction.
Answer: NH3 (base) and NH4+
(acid) |
|
(e) Zinc metal is placed in a solution of copper(II) sulfate. (i) Zn + Cu2+ → Zn2+ + Cu |
(ii) Describe the change in color of the solution that occurs as the reaction proceeds. Answer: The blue color of the solution due to the presence of the hydrated copper(II) ion fades as the copper(II) ion reacts and the colorless hydrated zinc(II) ion forms. |
|
(f) Hydrogen phosphide (phosphine) gas is added to boron trichloride gas. (i) PH3 + BCl3 → H3PBCl3 |
(ii) Which species acts as a Lewis acid in the reaction? Explain. Answer: BCl3 acts as a Lewis acid in the reaction because it accepts the non-bonded pair of electrons of the phosphorus atom in PH3. |
|
(g) A solution of nickel(II) bromide is added to a solution of potassium hydroxide. (i) Ni2+ + 2 OH− → Ni(OH)2 |
(ii) Identify the spectator ions in the reaction mixture. Answer: The spectator ions are the bromide ion (Br−) and the potassium ion (K+). |
|
(h) Hexane is combusted in air. (i) 2 C6H14 + 19 O2 → 12 CO2 + 14 H2O |
(ii) When one molecule of hexane is completely combusted, how many molecules of products are formed? Answer: 1 molecule of hexane produces 13 molecules of products. |
The examples given in the table represent one kind of question about each
reaction; there are many more such questions that can be asked, but recall that
these questions should not require the use of a calculator, which is not
permitted for Part B of Section II of the exam. If you ask your students to
write and answer a question about each reaction that they study, then they will
be very well prepared to tackle question 4 on the 2007 AP Chemistry Exam!
AP Practice Tests and Review Manuals
 |
AP Chemistry : Advanced Placement Examination |
| by Frederick J. Rowe | |
| Paperback - $17.00 |
 |
Chemistry 2000-2001 |
| by Princeton Review Editors | |
| Paperback - $17.00 |
 |
Chemistry : Principles & Problem Solving |
| Paperback - $17.00 Hardcover - $60.00 | |
 |
Master the AP Chemistry Test |
| by Brett Barker | |
| Paperback - $17.00 | |
 |
How to Prepare for the AP Chemistry |
| by Neil D. Jespersen | |
| Paperback - $15.00 |