ap free response questions chemistry

AP® Chemistry

Unit 1 | atomic structure and properties, short answer questions, interpreting pes spectra, interpretation of atomic structure, isotopes of bromine, long answer questions, periodic properties, percent yield from the dehydration of a hydrate, periodic trends, unit 2 | molecular and ionic compound structure and properties, bond length, formal charge, resonance, and lewis structures, localized electron bonding: properties of molecular geometry, unit 3 | intermolecular forces and properties, combustion analysis and gas laws, spectral analysis of unknown elements, intermolecular forces and boiling point, lewis structures and intermolecular forces, beer-lambert law lab, solubility of molecular compounds, gas law experimentation, interpreting particulate matter drawings, molecules: propane and n-propanol, metallic bonding: using a model to explain metallic properties, acid-base intermolecular interactions, matter and molarity, lab analysis of dyes, intermolecular and intramolecular forces, intermolecular forces of liquid chemicals, properties of matter based on bond type, unit 4 | chemical reactions, calculating volume and the ideal gas law, limiting reactant, percent yield, and net ionic equation, chemical and physical properties: explaining common occurrences, decomposition of ammonium dichromate, gravimetric analysis of a chloride sample, reaction between sulfuric acid and aqueous barium hydroxide, standardizing permanganate, gravimetric analysis of an insoluble substance, titration of an organic acid, identification of an unknown metal hydroxide, physical and chemical changes, unit 5 | kinetics, kinetics of decomposition, rate law using experimental data, reaction pathway between alkene and hydrobromic acid, experimental determination of reaction rates, kinetics graphing and rate laws, unit 6 | thermodynamics, patterns in combustion enthalpies, stoichiometry and calorimetry, stoichiometry and enthalpy in chemical reactions, comparing fuel gases, unit 7 | equilibrium, gas equilibrium, equilibrium: experimental design, le châtelier's principle and thermodynamics, disturbances in equilibrium, determination of $k_{eq}$ for a redox reaction, equilibrium and the haber process, activation energy, empirical formula of hydrate, heterogeneous equilibria: sublimation, unit 8 | acids and bases, calorimetry.

• SAP-10.A.2,

Qualitative Analysis of a Neutralization Reaction

Titration and molarity calculation, titration of an unknown concentration of acetic acid, molar mass of an unknown acid.

AP Chemistry Free Response Questions

Ap chemistry free response.

There are some great online resources available for AP Chemistry free response questions. Check out prior year questions and get tips and strategies for this portion of the exam.

Prior Year Questions

Course description questions, video solutions to 2018 frqs.

AP Chemistry | Practice Exams | Free Response | Notes | Videos |  Study Guides

Choose Your Test

Sat / act prep online guides and tips, ap chemistry frq: how to ace the free response questions.

Advanced Placement (AP)

Practicing free-response questions is one of the best things you can do to improve your AP Chemistry score. Not only will you excel on the free-response section, but you'll also know the material so well that the multiple-choice questions will be a piece of cake.

In this article, I'll tell you all about the free-response section of the exam, give you some tips on how to solve AP Chemistry FRQs, and go through a couple of sample problems from recent exams so you can get a feel for what they're like!

What's the Format of the AP Chemistry Free-Response Section?

The free-response section of the AP Chemistry exam seems intimidating because it's longer than free-response sections on most other AP tests, and it includes lots of calculations and experiments that you have to interpret.

The most important thing you can do is remain calm and stay focused and methodical in your approach to each question. It's not as scary or difficult as it looks if you've prepared well for the test and use your common sense!

Here's an overview of the format of the free-response section:

• 105 minutes (1 hour 45 minutes)
• Calculator use permitted
• Seven questions total
• Three long-response worth 10 points each
• Four short-response worth 4 points each
• The long-response questions always come first!

You'll be tested on the following skills (which may be tied to any topic in the AP Chemistry curriculum):

• Experimental design
• Analyzing real lab data to identify patterns and explain phenomena
• Creating or analyzing diagrams of molecules and atoms to explain observations
• Translating between different representations of data
• Following logical steps to analyze and solve problems

OK, that all makes sense, but how exactly do you solve these long, complicated questions? In the next section, I'll go through a step-by-step guide for how to approach the AP Chemistry FRQs .

How to Solve AP Chemistry Free-Response Questions

It's important to have a game plan for the free-response section. My first piece of advice is not to feel obligated to do the questions in order! Take a couple of minutes (no more than 5-10) at the beginning of the section to look through everything and decide which question you want to tackle first. It's best to start with your strengths so you'll have more time at the end for challenging questions.

You should spend a maximum of 20 minutes on each long free-response question and 10 minutes on each short free-response question. Keep an eye on the time so it doesn't get away from you! Here are some basic steps you should take to solve free-response questions:

Step 1: Figure Out What You Know

First, assess the information the question gives you. It can be confusing to extract the data that's embedded in the introduction over and over again as you go through different parts of the question. Make things easier for yourself by writing down the values you're given next to the question so that they're easily accessible when you need them. You should also take time to understand (at least on a general level) the experiment being described so that you don't feel confused and overwhelmed when you start reading the question.

Step 2: Dive Into the Question

For each part of the question, read the instructions and ask yourself the following:

Do you need to do any calculations?

Decide which equations you'll need (if applicable), and write them down. Do the necessary calculations based on the numbers you extracted in the previous step and any numbers you were given in this part of the question. Make sure you show your work! Don't erase your calculations, and double-check everything to make sure you have the correct units and your answer makes sense logically.

Does the question ask you to justify or explain your answer?

If so, don't ignore these instructions. In many cases, you'll only get points for your answer if you can explain it adequately. Use concrete evidence to back up your response (we're talking hard data). Even if something seems obvious to you, spell it out as clearly as possible to ensure that you earn those points!

Do you need to draw a diagram?

Even though neither of the free-response questions I'll go over in the next section requires this, some questions will ask you to draw diagrams. For example:

If you have to answer a question like this, try to be as clear as possible. Draw out your answer on scrap paper first if you feel unsure so that the final product is neat and unambiguous. Here's the answer, by the way:

Step 3: Double Check

Look back at the question to make sure you didn't miss anything or leave out any explanations. Reread each part and connect it directly to its corollary in your response so you're scooping up all the points you possibly can!

You should also walk through how you found each answer to make sure you didn't make any weird errors you missed the first time around.

Finally, check again for appropriate units. Errors in unit conversion are common silly mistakes that are really, really frustrating if you knew how to do the problem correctly otherwise.

AP Chemistry FRQ Examples

I'll go through the solution process for a sa mple question of each type so you can get a better idea of what the test will be like. Notice that these questions look complex and overwhelming at first, but if you stay calm and break them down methodically, they don't end up being that bad!

Long Free-Response Sample Question

Here's a sample long free-response question from the 2014 exam:

There's a ton of information here, so let's start from the beginning. What we know from the short intro is that the pH of a 0.20 M 50 mL sample of propanoic acid is 2.79 at 25 degrees Celsius. There's also an equation that shows how the acid reacts with water and which products are created by this reaction.

Now we're ready to tackle part (a):

Where's the conjugate acid-base pair in the equation? There are two pairs that you could potentially list for this answer:

CH 3 CH 2 COOH (acid) and CH 3 CH 2 COO - (base)

H30 + (acid) and H 2 0 (base)

We know that the first compound is propanoic acid, and the loss of the hydrogen atom through the reaction creates the basic compound on the right side of the equation. Conversely, the water in the first half of the equation is a base that becomes an acid when it picks up the hydrogen atom from the propanoic acid.

To get this point, you would need to label each compound indicating which is the acid and which is the base. Always read instructions carefully, or you may lose out on points - I can't say this enough!

Let's move onto part (b):

What's the value of K a for propanoic acid at the temperature indicated in the question? We just need to plug some values into the equation for K a , which is given to you on the formula sheet for the test:

Hmm, looks like we can't plug in the values yet because we don't know the molarity of the H 3 0 + , which would have to go in the [H + ] spot in the equation. We can find that value using this other equation from the formula sheet:

This means:

-pH = log[H + ] 10 -pH = [H + ] 10 -2.79 = [H 3 0 + ] 1.6 x 10 -3 M = [H 3 0 + ]

This value for the molarity of H 3 0 + is equal to the molarity of CH 3 CH 2 COO - . The same amount of each must be created by the equation because the hydrogen atoms are removed and added in a 1:1 ratio. Armed with this new information, we can go back to the K a equation:

K a = [H 3 0 + ][CH 3 CH 2 COO - ] / [CH 3 CH 2 COOH] K a = (1.6 x 10-3 M )(1.6 x 10-3 M ) / 0.2 M K a = (1.6 x 10-3 M ) 2 / 0.2 M K a = 1.3 x 10 -5

• One for correctly solving for [H 3 0 + ]
• One for plugging the right values into the K a equation
• One for solving for K a correctly

OK, now for part (c)!

Oh crap, this one has PARTS WITHIN THE PART. Don't panic; you got this. It's just true or false plus answer explanations! The explanations on these types of questions are very important. If you don't explain your answer adequately, you won't get any points even if the answer itself is correct. You can earn two points total on this question, one for each answer AND explanation.

In solution, the OH ions from the NaOH will react with the CH 3 CH 2 COOH to form water and CH 3 CH 2 COO - like so (hydrolysis reaction):

The pH of the resulting solution will be GREATER than 7 because of the formation of the new basic compound at equivalence. That means i t's false!

If two acid solutions have the same pH, but one is with hydrochloric acid, and the other is with propionic acid, would the first solution necessarily have a lower molar concentration of the HCl?

HCl is a strong acid that ionizes completely in solution while propionic acid only partially ionizes. Fewer moles of HCl are needed to produce the same molar concentration of H 3 0 + and reach an equivalent pH level to the propionic acid solution. This one is true!

The next part of the question offers up a new scenario, so let's take stock of what we've learned from the added description. So, the student titrates 25 mL of a ~mystery solution~ (mysterious squiggles added for dramatic flair) of propanoic acid with 0.173 M NaOH and reaches the endpoint of the titration after 20.52 mL of the NaOH has been added.

Now onto part (d)!

Based on this information, part (d) asks us to figure out the molarity of the propanoic acid.

First, how many moles of NaOH were put into the solution? We can find this by multiplying the total volume of NaOH solution by its molarity:

(0.02052 L NaOH) x (0.173 mol NaOH / 1 L NaOH) = 3.55 x 10 -3 mol

A total of 3.55 x 10 -3 moles of NaOH were put into the solution. Since the titration reached the equivalence point at this time, that means that the number of moles of NaOH added would have to be the same as the number of moles of propanoic acid in the original solution. If we divide 3.55 x 10 -3 mol propanoic acid by the number of liters of acid in the original solution, we will get the molarity:

3.55 x 10-3 mol propanoic acid / 0.025 L propanoic acid = 0.142 M

For this part, you get one point for correctly calculating the number of moles of acid at the equivalence point and one point for providing the correct molarity.

Part (e) is a critical thinking question about a new experiment.

Would the student have to use a different indicator to figure out the concentration of a solution of an acid with pK a of 4.83? Based on our K a calculations in part b, we can use one of the equations on the formula sheet to figure out pK a for the original propionic acid and compare the two values.

pK a = -logK a pK a = -log(1.3 x 10 -5 ) pK a = 4.89

The two pK a values of 4.83 and 4.89 are pretty close to one another, so you wouldn't need to use a different indicator in the new titration. The correct response is to disagree with the student's claim. You get one point here for disagreeing with the claim and explaining why, and you get a second point for directly comparing the two pK a values.

Short Free-Response Sample Question

Here's a sample short free-response question, also from the 2014 exam:

As you can see, the "short" questions aren't really that short, but they're not as involved as the long ones. There isn't as much information to digest, and each of the parts of the question is more direct. Each part of this question is worth one point (4 points total). Your response must include the correct answer and the correct justification/methodology to earn points!

Starting with part (a):

n = PV/RT n = (1.04 atm)(1.00 L)/(0.08206 L atm mol −1 K −1 )(1100 K) n = 0.0115 mol CO 2

Moving onto part (b):

In experiment 1, the original number of moles of CaCO 3 would be equivalent to 50.0 g / (100.09 g/mol). The 100.09 g/mol number was calculated by adding up the atomic weights of the elements in the compound. This calculation gives us 0.500 mol CaCO 3 total.

If all of it had decomposed, the figure we calculated in part a for the number of mols of CO 2 produced would also be 0.500 mol, but it was only 0.0115 mol. This discrepancy means that the student's claim has to be false!

Now let's tackle part (c):

What would happen if more gas was added to the container and the pressure went up to 1.5 atm? Would it go back down to 1.04 atm afterward?

Equilibrium was reached in both experiments, and it resulted in a final pressure of 1.04 atm. The reaction would just adjust to the added gas by shifting towards the reactant. The pressure would go back down to the equilibrium figure of 1.04 atm as the excess CO 2 was consumed. The final pressure would still be equal to 1.04 atm.

Finally, we'll answer part (d):

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How to Practice AP Chemistry Free-Response Questions

You can find AP Chemistry FRQs from previous years (and their solutions) on the College Board site. The exam was last significantly changed in 2014 (seven free-response questions instead of six, and no questions asking you just to balance equations), so keep in mind that the 2014 and onward exams will be the most accurate representations of what you can expect to see on your test. Here's a link to the most recent questions and answer explanations:

2014 to 2019 AP Chemistry Free-Response Questions

You can also view the 2021 FRQ and their scoring guidelines .

There is no login required for access to these questions. You can also check out my article that lists all the AP Chemistry practice tests and quizzes that are available online . There are a few more unofficial practice tests that include free-response questions modeled after the questions on the real exam.

The free-response section is the most challenging part of the AP Chemistry exam for most students. To do well, you need to have a strong understanding of all the major concepts covered in the course and be able to apply them to a variety of experimental scenarios. Most of these questions look intimidating, but they're manageable if you take them one step at a time and break them down into smaller chunks.

Here's a review of how to solve free-response questions:

• Write down any data that's included in the question
• Figure out which formulas you need
• Do the necessary calculations
• Justify your responses
• Draw diagrams if applicable
• Make sure your units of measurement are correct
• Verify that your answers make sense logically

Practice your skills on free-response questions from past AP tests until you feel comfortable. Remember, questions from tests before 2014 will be slightly different from the current free-response questions; base your expectations for the real test off the material from 2014 onward!

What's Next?

If you're looking for more AP Chemistry practice , check out my list of the best review books for this year's test. Almost all of them include free-response questions modeled after the current format of the exam.

For a holistic look at the most effective way to study for in-class assessments and the final exam , read my ultimate study guide for AP Chemistry.

Are you debating whether to start studying now or put it off a little longer? Learn more about when you need to get serious about your study plans for AP tests.

Want to improve your SAT score by 160 points or your ACT score by 4 points? We've written a guide for each test about the top 5 strategies you must be using to have a shot at improving your score. Download it for free now:

Samantha is a blog content writer for PrepScholar. Her goal is to help students adopt a less stressful view of standardized testing and other academic challenges through her articles. Samantha is also passionate about art and graduated with honors from Dartmouth College as a Studio Art major in 2014. In high school, she earned a 2400 on the SAT, 5's on all seven of her AP tests, and was named a National Merit Scholar.

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AP Chemistry Practice Tests

The AP chemistry exam is a two-part exam designed to take about three hours.

The first section has 60 multiple-choice questions. You will have 90 minutes to complete this section.

The second part of the exam is the free-response section. You will begin this section after you have completed and turned in your multiple-choice scan sheet. There will be a break before you begin the second section. The length of this break will vary from school to school. You will not be able to go back to the multiple-choice questions later.

You will receive a test booklet for the free-response section of the test. You will have 105 minutes to answer seven questions.

If you are a mobile user, click here: Do AP Chemistry Practice Questions .

AP Chemistry Multiple-Choice Practice Tests

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• AP Chemistry Practice Test 1: Atoms, Elements, and the Building Blocks of Matter
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• AP Chemistry Practice Test 8: Chemical Reactions, Energy Changes, and Redox Reactions
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• AP Chemistry Practice Test 13: Equilibrium, Acids and Bases, Titrations, and Solubility
• AP Chemistry Practice Test 14: Equilibrium, Acids and Bases, Titrations, and Solubility
• AP Chemistry Practice Test 15: Equilibrium, Acids and Bases, Titrations, and Solubility
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AP Chemistry Free-Response Practice Tests Online

• AP Chemistry Free-Response Practice Test 1: Atoms, Elements, and the Building Blocks of Matter
• AP Chemistry Free-Response Practice Test 2: Atoms, Elements, and the Building Blocks of Matter
• AP Chemistry Free-Response Practice Test 3: Bonding and Phases
• AP Chemistry Free-Response Practice Test 4: Bonding and Phases
• AP Chemistry Free-Response Practice Test 5: Chemical Reactions, Energy Changes, and Redox Reactions
• AP Chemistry Free-Response Practice Test 6: Chemical Reactions, Energy Changes, and Redox Reactions
• AP Chemistry Free-Response Practice Test 7: Chemical Reactions and Their Rates
• AP Chemistry Free-Response Practice Test 8: Chemical Reactions and Their Rates
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AP Chemistry Downloads

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AP Chemistry Free Response Questions (FRQs)

8 min read • july 17, 2020

Jordyn Haynes

Overview of AP Chemistry FRQs

The written response section or Free Response Questions of the AP Chemistry is the second and final section of the AP Chemistry exam. The FRQs are designed to test the 6 major concepts covered throughout the AP Chemistry Course:

Question and Method

Models and Representations

Representing Data and Phenomena

Model Analysis

Mathematical Routines

Argumentation

The FRQs will also cover other important concepts such as experimental design and analysis of lab data and observations and will also look for a logical path towards your answer. There are 7 FRQs on the exam: 3 long answer questions and 4 short answer questions (we will break down the specifics of these two types of questions in a later section). All questions are multi-step questions and will test a variety of topics and skills learned throughout the AP Chemistry course. 

For more info about these key concepts & skills straight from the College Board click here .

Exam Format 

As you know, the FRQ section on the AP Chem exam is 7 questions long (3 long, 4 short answer questions). You will have 1 hour and 45 minutes to complete the section. Your score on this section equates to 50% of your total exam score. Here is a clip of Dylan Black , a chemistry streamer, going over the format of the exam as a whole.

Short Answer vs Long Answer Questions

The short answer questions are single or multi-part questions that are scored out of a total of 4 points. The long answer questions are always multi-part and are worth a total of 10 points. A good breakdown of time for these questions would be:

10 minutes for each SAQ and 16 minutes for each LAQ

Here are the task verbs for the chemistry FRQ:

Image Courtesy of College Board

How to Ace the FRQ - Step by Step 

Step 1 - Read the Entire Question

Read each part of the question from top to bottom or bottom to top. Make sure you understand what each part of the question is asking before moving on. 

Step 2 - Break It Down 

Figure out your plan of attack. Make a list of any given information and call to mind the skills you need to apply to answer the problem. Determine if calculations are needed or if you have to draw a diagram. Also, look out for questions asking you to “prove” or “justify” your answer and then think about any theoretical topics you’ve learned that will help you validate your answer. 

Step 3 - Answer the Question

This is your time to shine! Use the information you have already organized to move through each problem. Apply all skills and perform all calculations. Make sure to answer all parts of the question and to justify your answer whether it be with a calculation, a rule/law, a trend, or theory.  Make sure to reference both substances in your justification/explanation.

Step 4 - Double-Check

Make sure you’ve answered everything. Are your units and/or the number of significant figures correct? Have you missed anything? Are your calculations accurate? Walk through each step of the problem and connect it to how you got your answer. 

Remember, you got this! Image Courtesy of GIPHY

AP Chemistry FRQ Tips

Concise and clear is key.

Write with precision and confidence. Convey your answer clearly and accurately--nothing more, nothing less. Don’t distract your reader with rambling or long-winded explanations and make sure to use proper grammar. 

Stay Consistent

Be careful to make sure all of your answers make logical sense and “add up” as you work from part 1 to the end of the problem

Cash In On Credit

In other words, maximize your credit on each problem. If a question has multiple answers make sure you select the best one. Always be sure to prove or justify your answer if applicable. You may get partial credit for any question so if you have any knowledge for any part of a question include it! 

Words and Symbols 

Sounds silly, but always be sure to accurately label your work. Make certain you correctly use terminology (ie. molecule, ion, mol, bond, atom, attraction, force, etc.)  and symbols (ie. k, K, M, m, etc.) 

Know Your Chemistry

It is super helpful to understand the major concepts and most important topics of Chemistry when trying to answer FRQs efficiently. Develop a good foundation with all of these but specifically intermolecular forces and periodic trends (as recommended by the College Board). Also, knowing your significant figures rules and conversion factors will boost your chances of getting every point possible! 

Example FRQ - Short Answer (4 points)

A student is performing an experiment with NO2(g). The gas is in a rigid container, originally at 300. K and 2.0 atm. The student increases the temperature of the gas to 450 K. 

Describe the effect of raising the temperature of NO2(g) on the movement of the NO2(g) molecules. 

Calculate the pressure in the container at 450 K. 

Use the Kinetic Molecular Theory to explain why the pressure of NO2(g) changes when the temperature is increased.  

The student measures the actual pressure of NO2(g) in the container and sees it is less than the pressure predicted by the ideal gas law. Explain why this occurred. 

Break Down 

The question includes information about a sample of gas & there are 4 questions to answer. 

What Do I Have to Do? Remember the Kinetic Molecular Theory and the Ideal Gas Law. Most gas questions can be broken down to those two concepts.

1A. As temperature increases, the gas molecules have a higher average amount of kinetic energy and move with a greater velocity. As a result, the pressure increases in a rigid container. The particles collide with the container walls with a greater amount of force.

1B . Use PV = nRT to calculate the new pressure at the higher temperature. All variables remain constant except pressure and temperature. Simplify down to 

P1/T1 = P2/T2   

(2.0 atm / 300. K) = ( P2 / 450. K)    

P2 = 3.0 atm

1C. According to the Kinetic Molecular Theory, the average kinetic energy of a sample of gas particles is directly proportional to the kelvin temperature. When the temperature of the gas sample is increased, the average kinetic energy also increased, resulting in a greater velocity. This resulted in a greater pressure at the increased temperature, since the number of collisions the molecules have with the walls of the container increased. 

1D. The real gas pressure is less than ideal gas pressure due to attractive forces between the NO2 gas particles. The NO2 molecule is polar and exerts attractive forces resulting in a lower gas pressure due to less molecules colliding with the container’s walls. 

Scoring Guidelines

See below for a quick breakdown of each point. 

1 point comes from correctly relating temperature to gas motion.

1 point comes from correctly calculating P2.

1 point comes from correctly justifying the relationship between Kinetic Molecular Theory to pressure and temperature.

1 point comes from correctly explaining the causes of “real” gas pressure.

Example FRQ - Long Answer (10 points)

Here is an example of the process described above for answering a free-response question. This is a long answer question, but the steps taken to answer all FRQs should be relatively the same. Begin by completing a thorough read-through of the entire question.

1. Answer the following questions regarding the photoelectron spectra for calcium and potassium.

A. On the PES spectra above write an X above calcium’s valence electrons. Justify your answer using Coulomb’s Law.

B. Explain WHY every peak for calcium is shifted slightly to the left of potassium.

C. Would the peaks for an ion of calcium (Ca2+) be shifted to the left, right or stay the same as the peaks of the calcium atom shown in the diagram?  Justify your answer.

D. Would the photoelectron spectra of 39K and 40K be the same or different?  If they were different, in what way(s)?  If they were the same, why?  Justify your answer.

E. Identify the element shown above.  

Write the electron configuration.

Explain to which energy level the shortest peak must (just to the right of 1.0 MJ/mol) must be assigned.  Justify your answer.

The question includes 2 PES graphs & there are 5 questions to answer. 

What Do I Have to Do? 

I have to draw an “X” above the peak that represents the valence electrons for calcium and use Coulomb’s Law to justify my answer. 

1A. The ‘X’ should be above the purple peak just to the right of 1 MJ/mol. This peak represents the valence electrons for calcium. The height equals 2 electrons and the position at the lowest binding energy means that those electrons are held onto with the least amount of energy. Using Coulomb’s law, the valence electrons are the furthest away from the nucleus and have the weakest interaction. There is significant shielding between the valence electrons and the nucleus resulting in the lowest binding energy. As the distance increases the energy decreases (inverse square relationship).

1B. Calcium has a higher effective nuclear charge than potassium, as a result the electrons are more tightly held than potassium’s electrons. This results in every electron in calcium having a slightly higher binding energy than the electrons in potassium.

1C. Stay the same, however, the peak for the valence electrons (the rightmost peak) would be missing. Both the calcium ion and calcium atom have the same effective nuclear pull, therefore the binding energy would be the same.  

1D. The PES spectra of the potassium isotopes would be the same. Both isotopes have the same number of protons, resulting in the same effective nuclear pull and the same binding energies for electrons in the electron clouds. Isotopes differ in number of neutrons which is irrelevant when discussing binding energies (ionization energies).

1E.  Scandium

1Ea. 1s2 2s2 2p6 3s2 3p6 4s2 3d1

1Eb. 3d1 This peak only has 1 electron and is filled after 4s2. It has slightly higher binding energy suggesting that it is NOT a valence energy level electron, this puts it in energy level 3. 

Calculations/Equations?

The exact source of points in an AP Chemistry FRQ differs on a problem to problem basis, but you will always get the points for the correct answer. However, the correct answer is not always the only point to scoop up for any given question. Points will often come from correct explanations, units, secondary calculations, or balancing an equation. You may also earn partial credit on FRQ problems for answers that follow the correct approach but have the wrong numeric answer or answers that have some but not all parts of the correct answer. 

1 point comes from correctly naming the location of the “X” AND 1 point for using Coulomb’s Law (effective nuclear charge) to justify the answer. See why justification and proving your answer is important? 

1 point comes from correctly justifying the location of calcium’s peaks.

1 point comes from correctly answering the question and 1 point for correctly justifying the answer. 

1 point comes from correctly identifying the element.

1 point comes from the correct electron configuration. 

1 point comes from the correct energy level and and for correctly justifying the answer. 

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Chemistry library

Course: chemistry library   >   unit 19.

• 2015 AP Chemistry free response 1a
• 2015 AP Chemistry free response 1b and c
• 2015 AP Chemistry free response 1d

2015 AP Chemistry free response 1e

• 2015 AP Chemistry free response 2a (part 1 of 2)
• 2015 AP Chemistry free response 2a (part 2/2) and b
• 2015 AP Chemistry free response 2c
• 2015 AP Chemistry free response 2d and e
• 2015 AP Chemistry free response 2f
• 2015 AP Chemistry free response 3a
• 2015 AP Chemistry free response 3b
• 2015 AP Chemistry free response 3c
• 2015 AP Chemistry free response 3d
• 2015 AP Chemistry free response 3e
• 2015 AP Chemistry free response 3f
• 2015 AP Chemistry free response 4
• 2015 AP Chemistry free response 5
• 2015 AP Chemistry free response 5a: Finding order of reaction
• 2015 AP Chemistry free response 6
• 2015 AP Chemistry free response 7

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