AP® Chemistry Free-Response Questions (FRQs)
Do you want to get a high score on the AP® Chemistry exam? If so, you have come to the right place! In this article, we will describe tactics so that you may do well on Section II of the AP Chemistry exam. This section contains the free response questions (FRQs) and can be intimidating because you have to come up with your own answers, unlike in the multiple choice section. To get full credit, you will need to perform various tasks, such as drawing particle diagrams or graphs, showing calculations to obtain a numerical answer, and providing concise explanations.
Section II consists of 7 FRQs and accounts for 50% of your exam score. This section may seem overwhelming at first, but if you know how to tackle the types of questions on this portion of the exam, you will be successful. Below, you will find tips on how to approach FRQs, task verbs commonly used in FRQs and their meanings, and a general overview of the types of FRQs you will see on the AP Chemistry exam.
How to Answer AP Chemistry Free-Response Questions & Examples
Success on the AP Chemistry exam depends on how well you know the content as well as whether you tackle the questions efficiently and use your time wisely. This section teaches you how to approach the FRQs to get the highest score possible and reach your goal on the AP Chemistry exam!
Know how the FRQs are scored
The FRQ responses are scored by AP Readers, who are AP Chemistry teachers and college instructors trained to use a specific scoring rubric to assign points for correct answers. A point is given when the reader sees that you have met a specific requirement stated in the scoring rubric. So the best way to score the maximum points is to prove your comprehension of each part of the question.
- Even though your AP Reader is an expert, you should write your answers like you are trying to explain the idea to someone who is not very familiar with chemistry.
- Be sure to write your responses in the lined space provided for each question.
- Write clearly and legibly using either a pencil or a pen with black or dark blue ink. If using a pen, be sure that it does not smear easily. The readers cannot give you credit if they cannot verify that you have met the requirements outlined in the scoring rubric. If you make a mistake, simply put a line through that part so that it will not be scored.
- Make sure to fully explain a concept and don’t omit any information necessary to demonstrate your understanding of the concept. For example, if you were asked to explain why one compound has a higher boiling point than another, it would not be sufficient to say that the compound with the higher boiling point has stronger intermolecular forces. You should mention the types of intermolecular forces each compound experiences and then compare the strengths.
- If you are asked a question based on an answer to a previous part of the question, you can earn full credit for the question even if your answer to the previous question is incorrect as long as your reasoning is correct based on that answer. For example, let’s say you were asked to calculate [H+] for a solution in the first part of one question, but you performed the calculation incorrectly. Then in a subsequent part of the same question, you are asked if the solution is acidic or basic based on the [H+] you calculated. If you calculate the pH correctly and answer this part of the question correctly (ie, solution is acidic or basic) based on the pH you calculated, you will get full credit for the latter part.
- Because you are not penalized for incorrect answers, you should attempt to answer each question if you have time. You will most likely know something about what the question is asking, so it doesn’t hurt to take a shot since there are various ways to earn a point for any given part of a question. The only way you are guaranteed to not earn any points is by not trying to answer the question! Give your best effort!
Pay attention to what the question is asking
Each FRQ on the AP Chemistry exam uses “task verbs” that ask you to do something specific. Pay attention to these words because they are usually associated with the points available on the scoring rubric. Therefore, if you correctly complete each thing that the task verbs in a particular question ask you to do, you will receive the maximum points possible for that question. Below you will find a list of common task verbs with examples to help you better understand what to do when you see them in a question.
- When you read a question, circle or underline each task verb and instruction. Consider what you must do to answer that part of the question.
- For questions requiring calculations, be sure to show your work, even if it’s a simple calculation. Don’t forget that you should wait until the end of a calculation to round your answer.
- If the question asks you to calculate a value, be sure to pay attention to significant figures, and don’t forget to add units using correct abbreviations to your answer if appropriate.
- To ensure you answer each item asked of you in a question, mark off the task verbs and instructions as you complete them. Make sure you complete each portion of a question before continuing on to the next question.
Use your time wisely
You have 105 minutes to complete Section II of the AP Chemistry exam. You should aim to spend approximately 20 minutes on each long FRQ (questions 1-3) and 10 minutes on each short FRQ (questions 4-7). This will leave you with approximately 5 minutes to look over your work or go back to any question about which you were unsure.
Be sure to read each part of a question before starting to write down any answers to give you an idea what the entire question encompasses. The best use of your time is to start by answering the parts of the question you feel most comfortable with. However, if one part of a question asks you to base the answer off of a previous part, you must answer the previous part first.
- If you get stumped on any part of a question, skip it and go to the next part. You can always come back to it at the end if you have time. You don’t want to spend too much time on any one question such that you are not left with an adequate amount of time to complete the other questions.
- If you have time left after completing each question, be sure to go back and review your answers to make sure you have answered all parts of each question.
Be clear and concise
The best way to ensure you score the maximum points possible on each FRQ is not necessarily to write as much as possible, but making sure that everything you write is directly answering what the question is asking. Giving details is OK, but make sure they are pertinent to the question. Concentrate on showing the reader that you understand the topic being tested. Answers should be written legibly and in complete sentences where appropriate. You won’t score points if you just mention key words without showing you understand how they apply to the concept. Therefore, avoid vaguely writing a lot of words hoping that one of them will earn you a point.
- Focus on what the question is specifically asking and be sure to not write information that is not relevant to the question. It is not necessary to restate the question in your answer.
- If you are given options in the question (eg, Does the temperature increase, decrease, or stay the same when the pressure is increased?), be sure to actually state one of the given options in your answer. In other words, don’t make up an option that isn’t given (eg, saying more information is needed to determine how the temperature will change).
- After answering the question, stop writing! There is no need to include extra information because you may end up contradicting something you said earlier, causing you not to earn a point where you would have otherwise.
- Only give the number of examples or draw the number of molecules/interactions, etc. on a diagram that a question asks. Providing extra examples is not encouraged because this will waste your time and these extra examples are not scored even if a previous example is incorrect.
- For math-based questions that require a numerical answer, think about whether the answer you calculated “makes sense” (eg, a negative number obtained for something like a concentration or mass doesn’t make sense).
- If you can’t remember the name for a specific term, try to explain it the best you can. Remember, you are trying to show that you understand the concepts.
Common Task Verbs and Their Meanings
There are several task verbs that are commonly used in AP Chemistry FRQs. You need to know what is meant by each task verb and the differences among them to write an effective FRQ response. Some task verbs are not terms that are commonly used in everyday language, and some of the task verbs used in FRQs overlap somewhat with one another. A good understanding of this terminology will help you earn the maximum number of points for each FRQ on the AP Chemistry exam.
This task verb requires that you apply mathematical steps (basic algebra, formulas from the provided Equations and Constants sheet) to arrive at a final calculated answer.
Example: Calculate the value of ΔH° for the reaction.
- For these types of questions, you should show your work, because this is usually worth a point in addition to the point you receive for arriving at the correct answer.
- Don’t forget to pay attention to significant figures and remember that you should wait until the end of the calculation to round.
- If applicable, you should include units with your answer.
- Unlike the multiple choice section, you are allowed to use an approved calculator on the FRQ section. Therefore, you shouldn’t feel the need to perform mathematical calculations in your head. Instead, use your calculator to speed up the process and ensure accuracy.
- Your final answer should be boxed so that it can easily be picked out by your reader.
2. Complete the diagram
This phrase means that you will need to finish a diagram (eg, Lewis electron-dot diagram, particle diagram) that will be provided in the question.
Example: Complete the Lewis electron-dot diagram for H2SO4 and show all bonding and nonbonding electrons.
- Pay attention to whether you are asked to provide labels in the diagram.
- Make sure your writing on the diagram is legible and that you only write what the question is asking, not more.
When you see this term, you will be expected to provide information about a particular process, topic, or experiment.
Example: Describe how you would prepare a 0.25 M solution of KCl(aq).
- You should strive to show that you understand whatever you are being asked to describe.
- A good way to show understanding is to provide a concrete example after your description of the topic.
- If you’re asked to describe the process of doing something in a lab, be sure to include the proper glassware you would use (eg, you would measure the volume of a liquid with a graduated cylinder, not a beaker or Erlenmeyer flask).
With this task verb, you will need to come to a decision or conclusion after evaluating specific information given to you in the question. This is a test of your critical thinking skills. You could also be asked to perform a calculation with this task verb.
Example: Determine whether your answer to part (a) above supports the student’s claim that the reaction is endothermic. Justify your answer.
- To earn maximum points, you should provide reasoning or evidence showing how you arrived at your determination.
Similar to ”complete the diagram,” you will be expected to create a type of visual representation of a concept. This could be a diagram, model, graph, or another type of representation. You may also be asked to draw something onto a diagram, such as an arrow, dotted lines to indicate interactions, or a peak on a graph
Example: Draw a particulate representation of the reaction products.
- You may also see the verb “represent” associated with this task verb (eg, Draw a peak on the graph to represent the 3s electrons.).
- After you draw your representation, you should think carefully about whether it needs labels, units, or a title, because these components are often worth points on your score.
- For particle diagrams, be sure to draw the molecules/ions in the correct physical state (ie, the reader should be able to tell whether something is a solid, liquid, or gas) and use correct stoichiometry.
Here, you will be required to estimate a specific value or parameter from given information (eg, graph, Lewis structure). You may also need to apply content knowledge to the given information to correctly answer the question.
Example: Based on the titration curve, estimate the pKa of the acid.
- Think about whether the value you are estimating has units associated with it; if so, make sure you include these units in your estimation.
7. Evaluate a claim
In this type of question, you will make a factual statement. This statement could be based on information from the question itself and/or from your content knowledge of the subject.
Example: A student claims that the acid-base indicator bromophenol blue is not a suitable indicator for the titration of 0.1 M HCl(aq) with 0.1 M NaOH(aq). Do you agree with the student’s claim? Justify your answer using the information provided in the table above.
- In your answer, you should state what you believe to be true about the claim given the available information and your background knowledge.
In this type of question, you must provide information about why a particular thing happened or the motivations or reasons for its occurrence. You may also need to discuss how something happened.
Example: A student noticed that the pH of the solution barely changed when 0.1 M NaOH(aq) was added to a solution. Explain this observation.
- It is generally a good idea to use specific examples or data provided in the question.
- Your goal should be to demonstrate that you can make a specific concept understandable to another person.
Here, you will need to indicate or give information pertaining to a specific subject.
Example: Identify the cathode in the galvanic cell.
- The “identify” task verb could also be in the form of “circle”, where you must circle something from a given list.
- Ensure you are doing exactly what the question is asking. For example, if a question asks you to circle a compound, make sure you circle it (instead of boxing it or marking it in another way).
- You should be excited when you see this task verb, because it is an easy one! This type of question is pretty straightforward, so remember to answer only what is asked.
- However, sometimes you may need to provide reasoning for your answer. Even if you are unsure about the reasoning, be sure to identify what is asked because you will typically receive a point for identifying and a point for the explanation.
This task verb requires you to provide evidence to show that a particular claim is true.
Example: Which acid is stronger, HNO3(aq) or CH3COOH(aq)? Justify your answer based on the particulate representation above.
- You may also be asked to provide reasoning explaining how your evidence supports, defends, or modifies the claim.
- This type of question generally requires the use of data provided in the FRQ.
Here, you will need to provide a reasoned, educated guess about the cause(s) or effect(s) of a change to a specific system, or provide the sign (positive or negative) of a given thermodynamic parameter.
Example: Predict whether the equilibrium position will shift toward the reactants, shift towards the products, or stay the same when more O2(g) is added to the reaction vessel. Justify your answer.
- Often, answering this type of question will include your reasoning about how you came to your prediction. This reasoning may include analysis of data.
12. Write an equation or expression
For these types of questions, you will need to write out a specific chemical equation based on information given in the question, or a mathematical expression that could be used to perform a calculation (eg, expression for an equilibrium constant).
Example: Write the net-ionic equation based on the balanced reaction shown above.
- Make sure your equation is appropriately balanced, if applicable.
- Include appropriate notation in your equation or expression.
FRQ Types on the AP Chemistry Exam
Section II on the AP Chemistry exam will follow a particular format. The first three FRQs are long questions worth 10 points each. The last four FRQs are short questions worth 4 points each. The FRQs will cover concepts and topics from all of the big ideas taught in AP Chemistry. Listed below are some general types of questions you could encounter in the FRQ section of the AP Chemistry exam.
- Examine molecular or atomic representations and draw conclusions
- Perform calculations using logical steps to arrive at an answer
- Analyze a particular experimental design
- Analyze experimental observations and provided data
- Interpret different type of representations
Great work making it to the very end! So you now have an idea about what the FRQ section of the AP Chemistry exam entails. The next step is preparing with high-quality AP Chemistry practice problems to master the skills you need to approach each of the seven FRQs you will encounter on the real AP Chemistry exam. If you practice these skills and keep the tips we provided here in mind, you can be confident in your abilities during this portion of the exam!
Frequently Asked Questions
There are 7 free-response questions in this section, which includes 3 long-answer and 4 short-answer questions on the AP Chemistry Exam. The MCQ section represents 50% of your score.
The AP Chemistry FRQ section is 1 hour and 45 minutes long (105 minutes).
You can find the AP Chemistry past exam free-response questions on the College Board® website.
Do you want to find strategies for answering MCQs? Check out UWorld’s How to Approach Guide to AP Chemistry Multiple Choice Questions with examples.
Do you want to know the ultimate tips and best resources for AP Chemistry? Read this for a step-by-step AP Chemistry study guide to score 5.
Not sure about how the AP Chemistry Exam Format is? Take a look at this article on types of questions, number of questions, topic-wise weight, and more!
Is AP Chemistry Exam Prep your priority? Check out this detailed article about the AP Chem Exam; why to take it, prerequisites, difficulty, and what’s on the exam.