AP Chemistry FRQ 2 Long Answer Practice
72 FRQ 2 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.
72 questions
sorted by unit
Magnesium isotopes and mass spectrum analysis
Unit 1: Atomic Structure and Properties
Answer the following questions about magnesium and its compounds.
Magnesium is a Group 2 element that exists naturally as a mixture of three isotopes. The mass spectrum of a pure sample of magnesium is shown in Figure 1.
Figure 1. Mass spectrum of magnesium (relative abundances of the three naturally occurring isotopes).
Using the data in Figure 1, calculate the average atomic mass of magnesium. Show your work.
Write the complete atomic symbol for the isotope corresponding to the peak at m/z = 26, including the atomic number and mass number.
A student analyzes a 2.018 g sample of a pure compound containing only magnesium and nitrogen. The results of the analysis are presented in Table 1.
Table 1. Composition of a Magnesium-Nitrogen Compound
Element | Mass in Sample (g) |
|---|---|
Magnesium | 1.458 |
Nitrogen | 0.560 |
Using the data in Table 1, calculate the number of moles of magnesium and the number of moles of nitrogen in the sample.
Based on your answer to part B(i), determine the empirical formula of the compound.
The photoelectron spectrum for a neutral magnesium atom is shown in Figure 2.
Figure 2. Photoelectron spectrum (PES) of magnesium showing electron binding energies and relative electron counts.
Based on the electron configuration of a neutral magnesium atom, identify the peak in Figure 2 that corresponds to the electrons in the 2p sublevel. Justify your answer in terms of the relative number of electrons.
The binding energy of the 2p electrons in a sodium atom (Na) is 3.67 MJ/mol. Explain why the binding energy of the 2p electrons in magnesium (Figure 2) is greater than that of sodium.
The first ionization energy of magnesium is 738 kJ/mol, while the first ionization energy of sodium is 496 kJ/mol. Explain this difference in terms of atomic structure.
What the FRQ 2 Long Answer asks
FRQ 2 is the second 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: Calculation
A first calculation or equation from the data
2 pts
Part B: Calculation or claim
Another calculation, or a claim supported by the data
2 pts
Part C: Reasoning
A calculation or an explanation of what the data show
2 pts
Part D: Justification
A claim justified with evidence, or a calculation from an earlier part
2 pts
Part E: Explanation
Why a result happens, in terms of particles or energy
1 pt
Part F: Prediction
How a change to the system affects the result, with a reason
1 pt
How FRQ 2 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(A-i): 1/1 point
Earned the point. You correctly wrote the equilibrium expression for Ka with the products in the numerator and the reactant in the denominator.
Part A(A-ii-1): 0/1 point
Did not earn the point. You did not show a setup or calculate the concentration of [H3O+].
Part B(B-i): 1/1 point
Earned the point. You correctly identified that pKa equals the pH at the half-equivalence point and determined the value to be 4.89.
Questions about the FRQ 2 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 2 different from FRQ 1 and FRQ 3?
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 3 Long Answer practice
FRQ 3 long-answer questions with the full setup and every part.
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 2 Long Answer
Pick one from the list, or let us choose for you.
Teaching AP Chemistry? Assign these FRQ 2 Long Answers to your class