AP Chemistry FRQ 3 Long Answer Practice
55 FRQ 3 long-answer questions written in the AP format. Pick one, read the full question, and write your response.
Your first scored response is included. A plan unlocks unlimited scoring.
55 questions
sorted by unit
Gallium properties and semiconductor applications
Unit 1: Atomic Structure and Properties
Answer the following questions about the element gallium (Ga).
Gallium is a group 13 element that is solid at room temperature but melts in the hand. It is commonly used in semiconductors.
Figure 1. Mass spectrum of gallium
The mass spectrum of a sample of naturally occurring gallium is shown in Figure 1.
Calculate the average atomic mass of gallium based on the data in Figure 1. Show your work.
Identify the difference in the atomic structure of the two isotopes represented by the peaks at 69 and 71.
Table 1. Experimental data for gallium oxide formation
Measurement | Mass (g) |
|---|---|
Mass of empty crucible | 24.500 |
Mass of crucible + gallium | 25.750 |
Mass of crucible + gallium oxide product | 26.180 |
A student heats a sample of pure gallium in a crucible in the presence of excess oxygen to form a gallium oxide compound. The data collected is shown in Table 1.
Calculate the number of moles of oxygen atoms in the final product.
Determine the empirical formula of the gallium oxide formed in the experiment. Show your work.
During the experiment, some of the solid gallium oxide product was spilled from the crucible before the final weighing. Would the calculated mass percent of gallium in the compound be greater than, less than, or equal to the actual mass percent? Justify your answer.
Figure 2. Photoelectron spectrum of gallium
The photoelectron spectrum (PES) for selected subshells of gallium is shown in Figure 2.
Write the complete ground-state electron configuration for the gallium atom.
Identify the peak (A, B, C, or D) in Figure 2 that corresponds to the electrons in the 3d subshell. Justify your answer based on relative peak intensity.
Indium (In) is in the same group as gallium but is in period 5. Explain why the atomic radius of indium is larger than the atomic radius of gallium.
The first ionization energy of gallium (579 kJ/mol) is lower than the first ionization energy of calcium (590 kJ/mol), even though gallium has a higher nuclear charge. Explain this phenomenon using principles of atomic structure.
What the FRQ 3 Long Answer asks
FRQ 3 is the last of three long-answer questions on the AP Chemistry exam: a 10-point problem in about six parts that mixes calculations, written explanations, and drawings. Each question splits its 10 points its own way, so the table shows one common split.
- 10 points
- usually across parts A to F
- 105 min
- for all seven FRQs
- 50%
- of your exam score comes from FRQs
Part A: Representation
Complete a Lewis diagram, write an equation, or identify a value
2 pts
Part B: Explanation
Explain a property or work a calculation from the data
2 pts
Part C: Calculation
A calculation from the data, with units
2 pts
Part D: Justification
A claim justified with evidence or a calculation
2 pts
Part E: Linked step
A calculation or explanation that uses an earlier result
1 pt
Part F: Conclusion
A final claim about the system, with the chemical reason
1 pt
How FRQ 3 Long Answer practice works
Each question follows the exam’s format, from the full prompt to a score on every part.
Read the full question
The setup, figures, data tables, and every part, laid out the way the exam shows them.
Write on a 23-minute timer
A pace that fits all seven questions into the 105-minute section. Pause it or turn it off, and your response saves as you go.
Submit for a score out of 10
Your response is scored against the scoring guidelines written for that question. Your first score is included.
Feedback on every part
A summary at the top tells you what to work on next. Below it, each part shows whether you earned the point and what the scoring guidelines were looking for.
Detailed Feedback
Part A: 1/1 point
Earned the point. You correctly completed the Lewis structure by drawing two lone pairs on the oxygen atom and three lone pairs on the chlorine atom (using lines to represent the pairs).
Part B: 0/1 point
Did not earn the point. You correctly identified that HClO2 has an extra oxygen atom and mentioned electronegativity, but you needed to explain the mechanism. To earn the point, you must explain HOW the extra oxygen makes it a stronger acid—specifically, that it withdraws electron density to weaken the O-H bond, or that it stabilizes the conjugate base.
Part C: 1/1 point
Earned the point. Based on the scoring guidelines, providing the correct final answer earns full credit for the calculation steps. Your correct final pH implies the correct setup and calculation of [H+].
Questions about the FRQ 3 Long Answer
How many responses can I get scored?
You can read every question without a plan. Your first scored response is included. A plan unlocks unlimited scoring.
Is FRQ 3 different from FRQ 1 and FRQ 2?
They share one format: 10 points, usually six parts, and a topic from any unit. Practice all three to prepare for the full long-answer set.
How are long-answer questions different from FRQs 4 to 7?
FRQs 1 to 3 are 10-point problems with about six parts that mix calculations, explanations, and drawings. FRQs 4 to 7 are 4-point questions that stay on one topic.
How do I type formulas, charges, and drawings?
Use the subscript and superscript buttons for formulas and ion charges. For a drawing, like a Lewis diagram or a mark on a figure, use the drawing tool, or switch the editor to handwrite, draw on paper, and add a photo of your page.
Can I use a calculator and the equations sheet?
Yes. The practice screen has a calculator and the AP Chemistry equations sheet with the periodic table, which you also get on exam day.
More AP Chemistry practice
FRQ 1 Long Answer practice
FRQ 1 long-answer questions with every part, figure, and data table.
FRQ 2 Long Answer practice
FRQ 2 long-answer questions, 10 points each, from every unit.
FRQ 4 Short Answer practice
FRQ 4 short-answer questions with the figure to draw on and both steps of part C.
FRQ 5 Short Answer practice
FRQ 5 short-answer questions with a student’s claim to evaluate.
FRQ 7 Short Answer practice
FRQ 7 short-answer questions with a diagram and two linked calculations.
Write your first FRQ 3 Long Answer
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