1972 exams loved a question that is now extinct: Qualitative Analysis Schematics.
Question 7: "A solution contains $Ag^+$, $Pb^2+$, and $Cu^2+$. Describe a procedure to separate and confirm each ion."
The Expected Answer (A flow chart in prose):
Problem: A 0.500-gram sample of a metal $M$ is burned in air. The resulting oxide, $M_2O_3$, weighs 0.711 grams. (a) Calculate the atomic weight of the metal $M$. (b) If the metal $M$ is reacted with excess $HCl$, what volume of $H_2$ gas at STP would be produced?
Directions: Write balanced net ionic equations for the following reactions.
1. Acetic acid is added to solid zinc metal.
2. Solutions of silver nitrate and sodium chloride are mixed.
3. Excess concentrated ammonia solution is added to a solution of copper(II) sulfate.
4. Chlorine gas is bubbled through a solution of sodium bromide.
The 1972 AP Chemistry free-response section is a classic set of problems that covers foundational topics still relevant to today's curriculum, including stoichiometry, acid-base chemistry, and coordination compounds. Core Topics and Question Overviews
Stoichiometry and Gas Laws: Question 1 involved a mixture of potassium hydroxide, potassium carbonate, and potassium chloride. You had to use titration data (with HCl and NaOH) and gas volume (from CO2cap C cap O sub 2
produced) to calculate the mass percentages of each component in the original 5.00g sample. Coordination Chemistry: This question focused on
. You were asked to relate experimental measurements—specifically the moles of AgClcap A g cap C l 1972 ap chemistry free response answers
precipitated and electrical conductivity—to the structural formulas of three different isomers: violet, light green, and dark green.
Organic Chemistry (Isomerism): Students had to identify and draw possible isomers resulting from substituting one chlorine and one bromine atom into ethane ( C2H6cap C sub 2 cap H sub 6 ) and ethene ( C2H4cap C sub 2 cap H sub 4
Energy and Electrochemistry: One problem required calculating standard free energy ( ΔGcap delta cap G ) and enthalpy ( ΔHcap delta cap H
) changes by using Faraday's constant and cell potential, highlighting the relationship between voltage and thermodynamic stability. Archived Solutions and Study Resources
Because the 1972 exam predates the digital archives of AP Central, educators have manually compiled these "legacy" questions:
Adrian Dingle’s Chemistry Pages: Offers a comprehensive AP FRQ Worked Answer Archive that includes step-by-step breakdowns for 1972 questions.
ChemmyBear: Provides specific handouts for the Coordination Chemistry (Ligands) question, including the expected structural formulas and reasoning.
Scribd & Weebly Guides: You can find detailed keys for the Gas Law problems and Acid-Base solutions through various teacher-uploaded repositories. AP FRQ WORKED ANSWER ARCHIVE
* 2024. 2024 1-7. 2024, 1. 2024, 2. 2024, 3. 2024, 4. 2024, 5. 2024, 6. 2024, 7. * 2023. 2023, 1. 2023, 2. 2023, 3. 2023, 4. 2023, Adrian Dingle's Chemistry Pages 16.17 ap chemistry frq 1972 energy
The 1972 AP Chemistry Free Response section is characterized by a high volume of questions and a significant emphasis on classical chemical calculations and descriptive chemistry, which distinguishes it from modern exam formats. Exam Structure & Format
In 1972, the Free Response section (Section II) was significantly more extensive than current versions: Duration: 110 minutes total.
Question Count: The exam featured 18 free-response questions in total. Modular Scoring: 1972 exams loved a question that is now
Part A & B: Focused on core conceptual questions (15% and 20% of the section grade). Part C: Required choosing one out of two questions (15%).
Part D (Net Ionic Equations): Students had to complete five out of eight equations (15%). Historically, these were presented using chemical names rather than formulas, adding a layer of nomenclature difficulty.
Part E (Problems): Students chose four out of six quantitative problems (35%). Content Highlights
A review of released questions from 1972 reveals several recurring themes that remain central to chemistry but were tested with different nuances:
Acid-Base Chemistry: One prominent question involved a complex mixture of potassium hydroxide, potassium carbonate, and potassium chloride. Students had to use titration data (NaOH and HCl) and gas volume (CO₂) to calculate the percentage composition of the original sample.
Organic Chemistry: The exam tested isomerism by asking students to identify and draw structures for chlorinated and brominated substitutes of ethane and ethene. Equilibrium: Questions often utilized ammonia ( NH3cap N cap H sub 3 ) and ammonium ( NH4+cap N cap H sub 4 raised to the positive power
) buffer systems to test understanding of hydrogen ion concentration stability. Historical Comparison
Tools: Unlike modern exams where graphing calculators are standard, 1972 students were provided with log tables for their free-response calculations.
Question Presentation: Net ionic equations were numbered as individual questions (e.g., questions 4–12) rather than sub-parts of a single larger question, which is why the total question count appears so much higher than today's seven-question format.
Nomenclature: There was a heavier reliance on knowing chemical names by heart, as formulas were often omitted in the prompts.
For students looking to practice with these archival materials, resources like the Adrian Dingle AP FRQ Archive and ChemmyBear provide historical compilations of these questions and their solutions. AP Chemistry Acid-Base FRQ Solutions | PDF - Scribd
By: AP Curriculum Historians
For decades, the Advanced Placement (AP) Chemistry exam has been the gold standard for high school college-level chemistry. While modern students focus on quantum mechanics and organic spectroscopy, the 1972 exam represents a fascinating "retro" challenge—a test built in an era of slide rules, log tables, and heavy emphasis on stoichiometry, equilibrium, and descriptive chemistry.
If you are searching for 1972 AP Chemistry free response answers, you are likely a tutor, a history buff, or a student using the legendary "Old AP Exams" for ultra-hardcore preparation. You have come to the right place.
Disclaimer: The original 1972 AP Chemistry exam is copyrighted by the College Board. The following answers are provided for educational commentary and historical analysis based on declassified materials and retroactive scoring guidelines. They are not official College Board publications but are accurate to the chemistry of the era.
The 1972 AP Chemistry Examination represents a classic era of the exam, focusing heavily on stoichiometry, gas laws, thermodynamics, and descriptive chemistry. While the curriculum has evolved, the fundamental principles tested in 1972 remain foundational for modern students.
Below are the reconstructed questions and worked solutions for the 1972 Free Response section.
Problem: Calculate the hydroxide ion concentration, $[OH^-]$, in a $0.10\text M$ solution of ammonium chloride, $NH_4Cl$. ($K_b$ for $NH_3 = 1.8 \times 10^-5$).
Question Summary:
The solubility product of ( PbF_2 ) is ( 3.7 \times 10^-8 ). Calculate:
(a) The molar solubility of ( PbF_2 ) in pure water.
(b) The molar solubility of ( PbF_2 ) in a 0.10 M ( NaF ) solution.
1972 Answer Key (Validated):
Score Rubric (1972): 5 points for part (a) – setup (2), cube root (2), units (1). 5 points for part (b) – common ion effect (2), approximation (2), final (1).
Modern AP Chemistry (post-2014) is less computational and more conceptual, but the 1972 exam builds mental math endurance. If you can solve the 1972 FRQs without a calculator, the modern exam (which allows a four-function calculator) becomes trivial.
Specifically, the 1972 questions on:
...are rigorous enough to prepare any student for a PhD qualifier. Question 7: "A solution contains $Ag^+$, $Pb^2+$, and