AP® Chemistry Multiple Choice Questions
How to Approach AP Chemistry MCQs & Examples
The first section of the AP® Chemistry exam consists of 60 multiple-choice questions (MCQs) and accounts for 50% of your overall score. This is a large portion of your score, but if you know how to tackle the various types of MCQs that appear on the exam, you should be able to ace this section. Each question type is distinct and must be approached in a different way to answer the question correctly.
Listed below are the question types that you will see on the AP Chemistry exam:
- Text-based questions
- Reaction equation- or chemical structure-based questions
- Diagram-based questions
- Experimental set-up-based questions
- Particle diagram-based questions
- Data table-based questions
- Graph-based questions
- Ranking-based questions
- Math-based questions
- Calculation required questions
- Math equation or expression answer choice questions
- Non-text answer choice questions
- Reaction equation answer choice questions
- Chemical structure answer choice questions
- Graph answer choice questions
- Particle diagram answer choice questions
- Passage-based questions
Below, we describe each question type, give you some tips about how to approach the question, and provide you with an example of each question type that you can expect to see on the AP Chemistry exam. Our UWorld AP Chemistry practice problems have hundreds of these questions, and we will show you an example of how we break down a specific question using our illustrated explanations. Practicing with AP-level questions and utilizing the tips we give will help you attain the highest score possible when you take the AP Chemistry exam!
Text-Based Questions
This type of MCQ requires you to analyze information given only in text form to arrive at the correct answer. Text-only questions are generally conceptual, but you should not presume that because there isn’t a graph, table, or diagram to analyze, this type of question is easy. Some text-based questions test more complex ideas.
Tips for Answering Text-Based Questions:
- Read the question thoroughly and mark the important information by circling or underlining the text
- Consider what you know about the concept the question is testing
- Go through the answer choices carefully and eliminate the answer choices that are clearly incorrect
- Select the answer that seems like the best fit and mark the question if you are unsure so that you can come back to it if you have time.
Below is an example of a text-based question.
MCQ 1 Example
A beaker contains 230 g of sucrose in 100 mL of water at 25 °C. After stirring the solution, some sucrose dissolves but some solid sucrose remains at the bottom of the beaker. The beaker is then heated to 90 °C and stirred again, and the solid at the bottom of the beaker completely dissolves. Which of the following is true?
- A) The dissolution of sucrose is endothermic.
- B) The dissolution of sucrose is exothermic.
- C) The dissolution of sucrose is endothermic at 25 °C and exothermic at 90 °C.
- D) The dissolution of sucrose is exothermic at 25 °C and endothermic at 90 °C.
What You Must Know:
To answer this question, you need to understand what the terms endothermic and exothermic mean and be able to decide whether one or both terms apply to the two scenarios described in the question.
To see an example of how UWorld helps you answer this type of question, click here to see an illustrated explanation of correct and incorrect answers and the pertinent background information.
Reaction Equation- or Chemical Structure-Based Questions
This type of question provides either one or more chemical reaction equations or chemical structures in the question stem with text generally below the reaction or structure. Sometimes, chemical reactions are accompanied by a numerical value next to the reaction, such as enthalpy, free energy, or an equilibrium constant. You generally need to apply content knowledge to the given reaction or structure to correctly answer the question.
Tips for Answering Reaction Equation- or Chemical Structure-Based Questions:
- Read over the question carefully, circling or underlining important information
- Carefully examine the reaction or chemical structure and make note of what type of reaction is presented (if applicable) and any other important given information
- Perform any necessary calculations or manipulations to the reaction (eg, determine the overall reaction, determine the net ionic equation)
- Review the answer choices and eliminate the ones you immediately know are incorrect
- Select the best answer but mark the question if you are unsure about the answer so that you can come back to the question if time allows at the end
Sometimes reaction equations or chemical structures may look intimidating, but don’t let them scare you! Read the question and see what it is asking so that you can focus on the aspects of the reaction or structure needed to answer the question. Below is an example of a reaction equation-based question.
MCQ 2 Example
Step 1: 2 NO(g) + H2(g) → N2(g) + H2O2(g)
Step 2: H2O2(g) + H2(g) → 2 H2O(g)
Based on the reaction mechanism above, which of the following are products in the overall reaction?
- A) H2O(g) only
- B) H2O(g) & H2O2(g) only
- C) H2O(g) & N2(g) only
- D) H2O(g), N2(g), & H2O2(g)
What You Must Know:
To correctly answer this question, you must know how to determine the overall reaction given the individual reaction steps and where the products are located in a reaction equation.
Diagram-Based Questions
This type of question gives a diagram in the question stem with text above, below, or both above and below the diagram. These questions can have diagrams that depict an experimental setup or a particle diagram. You will need to examine the diagram thoroughly to answer the question correctly.
Experimental setup questions require you to analyze the given diagram and apply your knowledge of the concept to answer the question. The setup could be something like paper chromatography, an electrochemical cell, or a titration. For some questions, you may need to perform calculations based on values you obtained from the setup diagram.
Particle diagrams given in question stems represent the molecules involved in a chemical reaction or a physical change. These diagrams are used to show the relative amounts of each molecule, so you should pay close attention to how many molecules are present in the diagrams and how they change.
Tips for Answering Diagram-Based Questions:
- Read over the question carefully, circling or underlining important information
- Carefully examine the diagram and make note of any important information or numerical values that seem pertinent to the question
- Read the answer choices and eliminate the ones you know are incorrect
- If you are unsure about the correct answer, pick the best answer and mark the question so you can return to it later if you have time at the end of the exam
Don’t be overwhelmed by an unfamiliar type of diagram; you are given all of the information needed to answer the question! Here is one example of a diagram-based question.
MCQ 3 Example
A galvanic cell is constructed with a Mg(s) anode and an Ag(s) cathode and produces an electric current, as represented in the diagram above. Which of the following statements correctly predicts the result of replacing the AgNO3(aq) solution with distilled water and provides the correct explanation?
- A) The cell will still produce an electric current because the Ag(s) can still be oxidized as the cell operates.
- B) The cell will no longer produce an electric current because there are no NO3-(aq) ions available to be reduced.
- C) The cell will no longer produce an electric current because there are no Ag+(aq) ions available to be oxidized.
- D) The cell will no longer produce an electric current because there are no Ag+(aq) ions available to be reduced.
What You Must Know:
To correctly answer this question, you need to know the purpose of the ionic solution in a galvanic cell and apply this concept to the galvanic cell modification described in the question.
Data Table-Based Questions
Questions of this type involve the addition of a table in the question stem along with text. You will have to use the data displayed in the table, along with any other information provided in the text of the question, to select the right answer choice. Sometimes, you may also need to apply your content knowledge to answer this type of question.
Tips for Answering Data Table-Based Questions:
- Read over the question carefully, circling or underlining important information
- Carefully look over the table, paying attention to the row and column headings (the units for numerical values in particular)
- Try to find patterns in the data, and circle any data that seem especially important to the question
- Read over the answer choices and mark out any that you know are incorrect
- If you are unsure of the correct answer, select the choice that seems best. However, make sure you mark the question so that you can return to it if you have time at the end of the test.
On the AP Chemistry exam, you will see both small and large data tables, but there is no need to be afraid of these. You just need to identify the important portion(s) for correctly answering the question. You will find an example of this question type below.
MCQ 4 Example
6 CO2(g) + 6 H2O(l) → C6H12O6(s) + 3 O2(g)
The formation of C6H12O6(s) and O2(g) during photosynthesis is represented by the equation above. Based on the information in the table below, which of the following is the overall enthalpy of the reaction?
| Substance | ΔH°f (kJ/mol) |
|---|---|
| O2(g) | 0 |
| H2O(l) | −285.8 |
| CO2(g) | −393.5 |
| C6H12O6(s) | −1273 |
- A) -5349 kJ/molrxn
- B) -2803 kJ/molrxn
- C) −593.7 kJ/molrxn
- D) +2803 kJ/molrxn
What You Must Know:
To correctly answer this question, you need to have a basic understanding of the heat of formation of a compound and how it relates to the enthalpy of a reaction. Using this knowledge, along with your calculation skills, you will be able to select the correct answer choice.
Graph-Based Questions
The question stem of graph-based questions will show you at least one graph displaying data and a text description of what is being shown. You will be required to use your content knowledge related to the type of information presented on the graph to analyze the given graph and select the best answer for the question. Similar to data table-based questions, graph-based questions can be intimidating at first because sometimes they contain a lot of information.
Tips for Answering Graph-Based Questions:
- After reading the question carefully, circle or underline important information.
- Examine the graph, paying close attention to the labels on the axes (especially the units), and the legend (if present).
- Mark any part(s) of the graph that seems especially relevant to the question.
- Read over the answer choices and cross out any that you know are incorrect.
- If you are unsure about the correct choice, select the answer that seems best to you. However, you should mark the question so that you can return to it if you have time at the end of the test.
If you follow the tips above, you will have no reason to be intimidated by graph-based questions! You can see an example below.
MCQ 5 Example
An acid is titrated with 0.10 M NaOH(aq), resulting in the titration curve shown above. Based on the titration curve, which of the following could be the acid being titrated?
- A) HC2H3O2(aq)
- B) HCI(aq)
- C) H2C4H2O4(aq)
- D) H3AsO4(aq)
What You Must Know:
This question relies on your understanding of acid-base titration, along with the equivalence point(s) of such titrations. Using the graph in the stem, you will apply your understanding of these concepts to select the best choice.
Ranking-Based Questions
These question types involve using given information, your content knowledge, or a combination of both to rank certain species (eg, elements, ions, molecules) based on a trend, property (eg, boiling point, bond polarity, bond length), or solution concentration. You will be given the items you are asked to rank and you will be told how to rank them (eg, least to greatest, lowest to highest) in the question stem.
Tips for Answering Ranking-Based Questions:
- After reading the question carefully, circle or underline important information. Pay close attention to the order in which the question asks you to rank the items.
- Consider what you know about the items you are asked to rank.
- Read over the answer choices and cross out any that you know are incorrect.
- If you are unsure about the correct choice, select the answer that seems best to you. However, you should mark the question so that you can return to it if you have time at the end of the test.
Keep reading for an example of a ranking-based question.
MCQ 6 Example
The relative sizes and ionic radii of the sulfide, bromide, and iodide anions are shown in the figure above. Based on Coulomb's law applied to the information in the figure, which of the following correctly arranges the anions in order of increasing strength of attraction to water molecules in solution (weaker attraction < stronger attraction)?
- A) S2- < Br- < I-
- B) Br- < S2- < I-
- C) I- < Br- < S2-
- D) S2- < I-- < Br-
What You Must Know:
This question requires knowledge of charge interactions, ion-dipole interactions, and Coulomb’s law. You will apply this knowledge to rank the given anions in order of increasing strength of attraction (ie, weaker attraction to stronger attraction) to water molecules in solution.
Math-Based Questions
This type of question involves taking information provided in the question stem and applying math of some kind to achieve the best answer.
For calculation required questions, you will be expected to perform a calculation to find the correct choice. Remember that calculator use is not permitted on the MCQ section of the exam. So be sure to practice these types of questions without a calculator so you will be better prepared for test day. Rounding or estimating can sometimes be helpful when doing math-based questions.
For equation or expression answer choice questions, you will need to select the appropriate equation or expression used to perform a particular calculation. These types of questions could also ask you to select the correct inequality expression for a given scenario (eg, value of equilibrium constant, sign of Gibbs free energy, comparison of concentrations at equilibrium).
Tips for Answering Math-Based Questions:
- Read over the question carefully, circling or underlining important information.
- You can use the blank space provided in your test booklet if you need to write out any calculations, but don’t make any stray marks on your answer sheet.
- Look over the answer choices and mark out any that you know are incorrect.
- If you are unsure of the correct answer choice, make your best guess, but remember to mark the question to come back to if you have time at the end of the exam.
Remember that you will have a provided Equations and Constants sheet as well as a periodic table to refer to as needed during these types of questions. Below you will find an example of this type of question.
MCQ 7 Example
P4(s) + 6 Cl2(g) → 4 PCl3(g) ΔH = −2440 kJ/molrxn
P4(s) + 10 Cl2(g) → 4 PCl5(g) ΔH = −3438 kJ/molrxn
Based on the enthalpies for the formation of PCl3(g) and PCl5(g) represented by the reactions above, how much heat is absorbed or released by the decomposition of PCl5(g) represented below?
- A) 250 kJ is absorbed
- B) 998 kJ is absorbed
- C) 250 kJ is released
- D) 998 kJ is released
What You Must Know:
In addition to basic math skills, you must also understand Hess’s law and the change of enthalpy in a system to perform the calculations required to answer this question.
Non-Text Answer Choice Questions
This type of question can be more complex or seem more intimidating than some other question types because rather than choosing a sentence, phrase, or numerical answer you must choose a non-text answer (eg, reaction equation, chemical structure, graph, diagram). The question stem could have a reaction equation, chemical structure, graph, or diagram in addition to the text, as well. Regardless, you will need to apply the given information and sometimes your content knowledge to answer the question.
For reaction equation answer choice questions, you must select the appropriate chemical reaction that represents the scenario described in the question.
Chemical structure answer choice questions require you to select the chemical structure of a molecule with a particular property (eg, largest/smallest bond angle, most/least soluble or polar). Don't be scared if you don’t know the identity of the compounds in the answer, just apply your knowledge of the particular property to select the structure that best answers the question.
Graph answer choice questions require you to choose the graph that correctly depicts what the question is asking. You will encounter different types of graphs on the AP Chemistry exam, including reaction energy profiles, titration curves, and molecule speed distributions. Pay close attention to the title and units of each axis.
For particle diagram answer choice questions, you must select the diagram that depicts what the question is asking (eg, reactants or products in a given reaction, components of a solution, arrangement of atoms in an alloy). You must apply the content knowledge you have learned to select the correct diagram.
Tips for Answering Non-Text Answer Choice Questions:
- Read over the question carefully, circling or underlining important information.
- Carefully examine each answer choice diagram, paying special attention to the number of molecules (stoichiometry), placement of molecules in the diagram (ie, is it a solid, liquid, or gas?), or arrangement of elements in an alloy, when pertinent.
- Eliminate any answer choices that are obviously incorrect.
- Choose the best answer, and if you are unsure, mark the question and come back to it if you have time left over at the end of the test.
Below is an example of a question with diagram answer choices.
MCQ 8 Example
The complete combustion of a particular sample of C2H2(g) (acetylene) was found to produce 8 moles of CO2(g) and 4 moles of H2O(g). Which of the following diagrams best represents the reactants before the reaction occurred? Note: Assume that each molecule shown represents 1 mole.
- A)
- B)
- C)
- D)
What You Must Know:
To correctly answer this question, you must understand the law of conservation of mass and how to be able to write a balanced chemical reaction given the type of reaction and how much product formed. Based on the stoichiometry of the balanced reaction, you should be able to identify the diagram that corresponds to the reactants.
Passage-Based Questions
This type of question is a little different from the standalone question types because passage-based questions are tied to a particular passage on the exam. Passages are generally fairly short, but some may be longer, and sometimes they contain multiple figures, including reactions, drawn images, data tables, and/or graphs. A few passages may contain text only, while others may contain a single figure, such as a table or graph, with no additional text. In addition, passages may introduce one or more experiments or describe a chemical process.
Each passage will contain 3-5 questions pertaining to that passage. Any of the previously introduced question types may be found as a passage-based question. Usually, these questions will rely on information given in the passage in order to select the best answer. Sometimes, you will also need to apply your content knowledge in addition to the passage information to arrive at the best choice.
Tips for Answering Passage-Based Questions:
- Read the passage fairly quickly and examine any figures (eg, reactions, graphs, tables, diagrams) present. You shouldn’t spend too much time trying to figure out everything about the passage until you have read the questions. Underline information you think may be important.
- Read the question carefully, circling or underlining critical information. Pay attention to information given in the question about where to look in the passage to find the answer (eg, “Based on Figure 2…”).
- Go back to the passage as directed by the question and focus on the relevant part(s) of the passage.
- Read through the answer choices and mark out any that are obviously incorrect.
- If you are not sure about the correct answer, select the answer that seems best. However, make sure to mark the question so that you can return to it if you have time at the end of the test.
Although passage-based questions can inherently seem more complex than other question types, there is no reason to be frightened by these questions if you follow the tips here! Keep reading to see an example of this type of question. First, read the passage, and then try answering the associated question.
MCQ 9 Example
The full photoelectron spectrum of a neutral atom of an unidentified element X is given above. The exact binding energy values measured are listed above each peak.
Question
During the second ionization of an atom of element X, an electron is removed from the
- A) 1s sublevel
- B) 2s sublevel
- C) 2p sublevel
- D) 3s sublevel
What You Must Know:
This question requires knowledge of determining electron configuration and ionization energy of an unknown element. You will use this knowledge to analyze data in the passage figure and choose the appropriate sublevel from which an electron is removed during the second ionization of an atom of this element.
Now that you know the types of MCQs you will encounter on the AP Chemistry exam, you will be prepared with the necessary skills to take on any question you encounter. The key to success on the AP Chemistry exam is thorough preparation, and knowing these question types is just one more way you are prepared to do your best and achieve a high score!
Frequently Asked Questions
How many multiple-choice questions are on the AP Chem Exam?
Can you use a calculator on the MCQ section of the AP Chem Exam?
How are AP Chemistry multiple-choice questions graded?
How long is the multiple-choice section of the AP Chemistry Exam?
When can I get the AP Chemistry past exam MCQs?
Collegeboard offers AP Chemistry past exam MCQs through AP Classrooms — this is a free medium that offers online instructional resources and tools to AP teachers and students regardless of their learning environment.