AP Chemistry FRQ Room

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AP Chemistry Free Response Questions

The best way to get better at FRQs is practice. Browse through dozens of practice AP Chemistry FRQs to get ready for the big day.

  • View all (250)
  • Unit 1: Atomic Structure and Properties (16)
  • Unit 2: Molecular and Ionic Compound Structure and Properties (18)
  • Unit 3: Intermolecular Forces and Properties (23)
  • Unit 4: Chemical Reactions (30)
  • Unit 5: Kinetics (24)
  • Unit 6: Thermodynamics (28)
  • Unit 7: Equilibrium (57)
  • Unit 8: Acids and Bases (36)
  • Unit 9: Applications of Thermodynamics (18)
Unit 1: Atomic Structure and Properties

Application of the Ideal Gas Law: Gas Evolution Reaction

A chemical reaction conducted in a closed system produces a gas that is collected at Standard Temper

Medium

Atomic Structure and Isotopic Abundance Analysis

This question examines how the periodic table information relates to an element's internal structure

Medium

Average Atomic Mass Calculation from Isotopic Data

An element has the following isotopic data as shown in the table. Using the data, answer the followi

Easy

Bohr Model, Energy Levels, and Electron Transitions

Examine the Bohr model of the hydrogen atom.

Medium

Calculating Moles in Gaseous Samples Using the Ideal Gas Law

At STP, a student collects a gas sample that occupies $$44.8\,L$$. Answer the following:

Easy

Calculation of Gas Moles from Volume at STP

A gas is produced in a reaction and collected at STP, occupying a volume of 11.2 L. Use the molar vo

Medium

Correlation Between Atomic Radius and Electronegativity in Periodic Trends

Atomic radius and electronegativity are fundamental periodic trends that are inversely related. Desi

Hard

Electronegativity and Bond Polarity

A researcher examines how differences in electronegativity affect bond polarity. Consider the compou

Easy

Empirical Formula Determination from Percent Composition

An unknown compound is found to have a percent composition of 40.0% sulfur, 13.3% hydrogen, and 46.7

Medium

Isotopic Abundance Analysis for Carbon

An experiment was conducted to measure the isotopic composition of carbon. The data collected show t

Medium

Limiting Reactants: Combustion of Carbon

Consider the combustion reaction of carbon in oxygen to form carbon dioxide: $$C + O_2 \rightarrow C

Medium

Mass Spectrometry Analysis of Selenium Isotopes

Researchers obtained a mass spectrum for selenium showing five naturally occurring isotopes with the

Medium

Periodic Trends and Atomic Structure Analysis

A researcher is investigating periodic trends by examining how atomic radius and ionization energy v

Easy

Photoelectron Spectroscopy Analysis

A photoelectron spectrum (PES) provides information on the binding energies of electrons in various

Hard

Predicting Ionic Charges in Compound Formation

Use periodic trends to predict ionic charges and formulate compounds.

Easy

Reaction Rate Dependence on Molarity: A Kinetic Study

The rate of a reaction often depends on the molarity of the reactants. Design an experiment to inves

Medium
Unit 2: Molecular and Ionic Compound Structure and Properties

Bonding Type and Solubility

The type of bonding in a substance can significantly influence its solubility in various solvents. A

Medium

Comparative Analysis of Bonding Types and Electrical Conductivity

The conductivity of substances in various phases gives insight into their bonding. Compare the elect

Hard

Comparative Conductivity Analysis

A table detailing the conductivity of various substances based on their bonding type, in different s

Hard

Comprehensive Lewis Structure and Formal Charge Analysis in Sulfate Ion

This question requires you to integrate several concepts in Lewis structure construction, resonance,

Extreme

Designing an Experiment on Ion Mobility in Solutions

Design an experiment to investigate the factors influencing the mobility of ions in an aqueous solut

Extreme

Exploring Expanded Octets and Their Applications

This question focuses on the concept of expanded octets and asks you to both explain the phenomenon

Hard

Formal Charge and Stability of Molecules

This question focuses on the role of formal charge in determining the stability of a molecule. You w

Medium

Formal Charge Calculation in Nitrate Ion

The nitrate ion (NO3⁻) exhibits resonance, which affects how formal charges are distributed among th

Hard

FRQ 11: Ionic vs. Molecular Bonding – Conductivity and Melting Points

A table compares the melting point and conductivity properties of an ionic compound (NaCl) and a mol

Easy

FRQ 16: Predicting Bonding Trends using Coulomb's Law

A table compares several ionic compounds with details on ion charges and approximate lattice energie

Hard

Investigating Bond Energy and Reaction Kinetics in Ionic Compounds

This question examines the relationship between ionic bond energy and reaction kinetics, using disso

Hard

Lewis Structure and Incomplete Octet of Boron Trifluoride

Boron trifluoride ($$\text{BF}_3$$) is an example of a molecule where the central atom does not comp

Easy

Measuring Bond Strength via Differential Scanning Calorimetry (DSC)

A research group employs differential scanning calorimetry (DSC) to determine the bond dissociation

Extreme

Metallic Bonding and Electrical Properties

A researcher publishes a claim that all metals, due to their 'sea of electrons,' exhibit maximum ele

Medium

Solubility and Conductivity Comparison Misinterpretation

A student compares the electrical conductivity of aqueous solutions of sodium chloride (an ionic com

Easy

Studying Lewis Structures and Their Limitations

This question focuses on constructing Lewis structures for compounds that can exhibit expanded octet

Medium

Temperature Dependence of Resistivity in Metals

The resistivity (ρ) of a metal changes with temperature according to the equation $$\rho = \rho_{0}

Medium

Vibrational Spectroscopy and Bond Force Constant Calculation

Vibrational spectroscopy can provide insight into bond strength. Using a diatomic molecule as a mode

Extreme
Unit 3: Intermolecular Forces and Properties

Analysis of Chromatography Retention Factors in Solvent Systems

Investigate the effect of compound polarity on retention factors in a paper chromatography experimen

Easy

Analyzing a Diagram of Kinetic Molecular Theory

Review the provided diagram intended to represent kinetic molecular theory. Evaluate its effectivene

Extreme

Beer’s Law and Concentration Measurement

A solution containing a colored compound is analyzed using a spectrophotometer. The measured absorba

Easy

Chromatographic Separation using Retention Factor (Rf)

This question involves analyzing chromatographic data to determine Rf values and to infer polarity o

Medium

Chromatography and Separation of Mixtures

Consider a laboratory experiment utilizing paper chromatography to separate a mixture of colored dye

Medium

Chromatography Data Analysis for Ink Separation

Analyze the chromatographic separation of ink components to determine the polarity of the pigments.

Easy

Chromatography: Analyzing Retention Factors in Separation

Analyze the data obtained from a chromatography experiment to understand how retention factors (Rf v

Easy

Column Chromatography for Dye Separation

A laboratory technician aims to separate a mixture of dyes using column chromatography. The separati

Easy

Correlation of Intermolecular Forces and Vapor Pressure

Examine how vapor pressure is affected by the strength of intermolecular forces using the provided e

Medium

Coulombic Forces in Ionic versus Covalent Bonds and Phases

Coulombic attractions are responsible for the high melting and boiling points in ionic solids, where

Extreme

Determining Molar Mass from Gas Density Measurements

Using the provided density data, explain how the molar mass of a gas can be calculated and what tren

Easy

Fractional Distillation Analysis

Analyze a fractional distillation curve to identify the separation of mixture components and relate

Medium

Gas Density and Molar Mass Determination

This question involves deriving a relationship between a gas's density and its molar mass, and then

Medium

Gas Density and Molar Mass Determination

A researcher uses measurements of a gas's density to determine its molar mass through the ideal gas

Medium

Intermolecular Forces and Vapor Pressure

The strength of intermolecular forces (IMFs) has a direct impact on the vapor pressure of a liquid.

Hard

Intermolecular Forces and Vapor Pressure: A Multi-Phase Analysis

A researcher is examining how differences in intermolecular forces affect the vapor pressure of liqu

Extreme

Interpreting Dipole Moments and Lone Pair Effects in Molecular Geometry

A student measures the dipole moments of various molecules to study the impact of lone pair electron

Medium

Maxwell-Boltzmann Diagram: Temperature and Speed Distribution

Analyze the Maxwell-Boltzmann distribution graph provided to determine how temperature affects the d

Hard

Molecular Polarity Analysis: Comparing CF4 and NF3

A researcher claims that the molecular polarity of a compound depends not only on the polarity of in

Medium

Molecular Polarity and Bonding Effects

This question asks you to analyze the factors that control bond polarity and how molecular geometry

Easy

Paper Chromatography Separation of Pigments

In paper chromatography, the separation of mixture components depends on solute–solvent polarity int

Medium

Phase Changes and Bond Energy Considerations

A chemist is investigating the energy requirements for phase transitions in substances characterized

Hard

Vibrational Energy Transitions

The energy absorbed during a vibrational transition in a molecule is given by $$E = h*v$$, where h i

Hard
Unit 4: Chemical Reactions

Acid-Base Equilibria and Amphoteric Behavior of Water

A buffer solution is prepared using acetic acid (HC2H3O2) with a concentration of 0.20 M and its con

Medium

Acid-Base Reaction and Titration Analysis

This FRQ investigates acid-base reactions and titration analysis. Consider the neutralization reacti

Medium

Balancing Redox Half-Reactions

Consider the redox reaction: $$Fe + 2 HCl \rightarrow FeCl_{2} + H_{2}$$. Analyze the oxidation-redu

Medium

Chemical Equilibrium in Acid-Base Reactions

A researcher examines the equilibrium established in the acid-base reaction of acetic acid with wate

Easy

Chemical Equilibrium: Le Chatelier’s Principle

For the equilibrium reaction $$N_2 (g) + 3*H_2 (g) \rightleftharpoons 2*NH_3 (g)$$, analyze the syst

Medium

Complex Ion Formation: Analysis of Oxidation States

In a reaction involving complex ion formation, the oxidation state of a metal M changes upon ligand

Extreme

Designing and Evaluating a Redox Titration Experiment for Unknown Concentration

A chemist must determine the unknown concentration of a \(Cu^{2+}\) solution. The proposed method is

Extreme

Detailed Redox Reaction Analysis

A researcher investigates a redox process in which oxalate ions ($$C_2O_4^{2-}$$) are oxidized by pe

Medium

Determination of Oxidation States

Assign oxidation states to the elements in the following compounds:

Medium

Dilution of Hydrochloric Acid Solution

A laboratory procedure requires the preparation of 500.0 mL of a 1.00 M HCl solution from a 12.0 M s

Easy

Experimental Design: Reaction Rate and Stoichiometry

Design an experiment to investigate the reaction rate of a synthesis reaction where multiple variabl

Hard

FRQ 4: Redox Titration with Permanganate

A redox titration employs $$KMnO_{4}$$ to determine the concentration of an unknown oxidizing agent.

Hard

FRQ 10: Analysis of Percent Error in Calorimetry

In a calorimetry experiment to measure the enthalpy change of an exothermic reaction, the expected t

Easy

FRQ 19: Designing a Redox Titration Experiment for Unknown Concentration

In a redox titration, $$KMnO_{4}$$ is used to titrate an unknown $$Fe^{2+}$$ solution. The claim is

Extreme

Gravimetric Analysis for Alkali Hydroxides

A 4.33 g sample of an unknown alkali hydroxide is completely dissolved in water. Upon adding an exce

Hard

Gravimetric Analysis for Determining Unknown Alkali Hydroxide

A 4.33 g sample of an unknown alkali hydroxide is dissolved in water and reacted with $$Cu(NO_3)_2$$

Hard

Integrated Multi-Reaction Stoichiometry and Redox Analysis

A laboratory procedure involves a compound containing both copper and iron. This compound undergoes

Extreme

Investigation of Acid-Base Neutralization Reaction

A chemist studies the neutralization reaction between hydrochloric acid (HCl) and sodium hydroxide (

Easy

Kinetics of Decomposition Reactions

A researcher is studying the kinetics of hydrogen peroxide (H2O2) decomposition at various temperatu

Medium

Multi-Variable Effects on Reaction Kinetics

Reaction kinetics are often influenced by several factors at once. Design an experiment to study the

Extreme

Oxidation-Reduction Reaction: Iron and Hydrochloric Acid

A student designs an experiment where iron metal reacts with hydrochloric acid to produce iron(II) c

Medium

Precipitation Reaction and Solubility Analysis

When aqueous solutions of silver nitrate (AgNO3) and sodium chloride (NaCl) are mixed, a precipitate

Medium

Precipitation Reactions and Solubility Rules

When 0.50 M AgNO3 is mixed with 0.50 M NaCl, a white precipitate is observed.

Easy

Quantitative Analysis of Combustion in Hydrocarbons

A 1.50 g sample of an unknown hydrocarbon is combusted, producing 3.30 g of $$CO_2$$ and 1.35 g of $

Hard

Reaction Kinetics of a Decomposition Reaction

The decomposition of compound A follows first order kinetics. The following table provides the conce

Hard

Reaction Rate Analysis through Graphical Data Interpretation

A researcher measures the concentration of a reactant during a decomposition reaction over time to a

Medium

Redox Reaction and Oxidation States

Consider the redox reaction between copper(II) ions and metallic iron: $$Cu^{2+}(aq) + Fe(s) \righta

Hard

Stoichiometry in Multi-step Reactions

A reactant A undergoes a two-step conversion to product C via an intermediate B. The reactions are:

Hard

Synthesis Reaction and Stoichiometric Calculations

An industrial process synthesizes compound AB via the reaction $$A + B \rightarrow AB$$. In a partic

Medium

Thermodynamic Calculations: Gibbs Free Energy Change

For a given reaction, the enthalpy change is $$\Delta H = -150.0\ kJ/mol$$ and the entropy change is

Extreme
Unit 5: Kinetics

Advanced Data Analysis for Second-Order Reactions

An experiment investigating a second-order reaction provides a plot of $$1/[A]$$ versus time that sh

Extreme

Arrhenius Equation and Activation Energy Determination

A reaction was studied at several temperatures, and the corresponding rate constant $$k$$ was determ

Hard

Arrhenius Equation and Temperature Dependence

Experimental data for a reaction were collected at various temperatures. The Arrhenius equation rela

Hard

Calculating the Rate Constant Using Concentration-Time Data

For a reaction known to be first order, answer the following parts based on integrated rate law anal

Medium

Catalyst-Mediated Reaction and Energy Profile Comparison

For the reaction $$\text{A} + \text{B} \rightarrow \text{C}$$, a catalyst is introduced which alters

Medium

Collision Theory and Reaction Rates

For a gas‐phase reaction, collision theory postulates that the rate of reaction is proportional to t

Easy

Complex Effects of Reactant Concentration on Reaction Mechanisms

A reaction is studied by varying the concentrations of reactants A and B. The following data were ob

Hard

Deriving Net Rate Law from Multi-Step Reaction Mechanism

Consider the following two-step reaction mechanism: I. $$M \rightarrow N$$ (fast equilibrium) II.

Hard

Determination of Reaction Order from Initial Rate Data

Using the experimental data provided for the reaction $$A + 2*B + C \rightarrow D$$, analyze how the

Medium

Determination of Reaction Order from Time-Dependent Concentration Data

A reaction involving a single reactant A was monitored over time. The concentration data (provided b

Medium

Determination of Reaction Order from Time-Dependent Data

A reaction is monitored by following the concentration of reactant A over time. Use the data provide

Medium

Determining Arrhenius Constants from Temperature-Dependent Rate Data

A study was conducted to measure the rate constant $$k$$ for a reaction at different temperatures. T

Extreme

Determining Reaction Mechanism from Kinetic Data

Experimental studies of the reaction 2A + B → C yield a rate law of the form Rate = k [A]^2[B]. a.

Extreme

Energy Profile Diagram Misinterpretation in Exothermic Reactions

In an investigation of an exothermic reaction, a researcher constructed an energy profile diagram ba

Medium

Graphical Analysis of First-Order Kinetics

A chemist monitors the concentration of reactant A in a reaction over time. The graph of ln[A] versu

Easy

Graphical Determination of Reaction Order

Different integrated rate law plots can be used to determine the reaction order. Answer the followin

Hard

Impact of Stirring on Reaction Rate in Homogeneous vs. Heterogeneous Mixtures

Stirring is often used in chemical reactions to improve mixing. Compare the effects of stirring on r

Medium

Integrated Rate Law Analysis for a Second Order Reaction

A second order reaction was investigated by monitoring the concentration of reactant A over time. Th

Medium

Investigation of an Intermediate in a Multi-Step Reaction

A reaction proceeds through the following mechanism: Step I: $$A \rightarrow X$$ (fast) Step II: $

Hard

Kinetic Isotope Effect Analysis

The kinetic isotope effect (KIE) is observed when a hydrogen atom in a reactant is replaced by deute

Hard

Pressure Effects on Gas-Phase Reactions

For a gas-phase reaction, the rate is dependent on the frequency of collisions, which is influenced

Medium

Rate Constant Determination for a First Order Reaction

A chemist monitored the concentration of reactant A in a first order reaction over time. The resulti

Medium

Synthesis Investigation: Determining Reaction Orders in a Complex Reaction

Investigate the kinetics of the complex reaction $$2X + Y \rightarrow Z$$. Using initial rate data g

Extreme

Time-Resolved Kinetics and the Steady-State Approximation for an Intermediate

An intermediate X in a reaction mechanism is monitored over time using time-resolved spectroscopy. T

Extreme
Unit 6: Thermodynamics

Analysis of Bond Energy Contributions in a Reaction

Consider the chlorination of methane as represented by the reaction: $$CH_4 + Cl_2 \rightarrow CH_3C

Hard

Analysis of Endothermic Dissolution Temperature Changes

A student studies the temperature change resulting from dissolving 10.0 g of a salt in 100.0 mL of w

Easy

Analyzing Enthalpy Diagrams of Reactions

A reaction's energy diagram shows reactants at 100 kJ/mol, a maximum energy of 150 kJ/mol (activatio

Medium

Bond Energy Calculations in a Reaction

Consider the synthesis of ammonia given by the reaction: $$N_2(g) + 3 H_2(g) \rightarrow 2 NH_3(g)$$

Medium

Calorimetry Experiment: Specific Heat Measurements

A student uses a calorimeter to determine the specific heat of an unknown metal. The metal (mass = 5

Medium

Calorimetry in Action

A reaction in a coffee-cup calorimeter results in a temperature change in the surrounding water. Sup

Medium

Comparative Study of Enthalpies of Formation for Organic Compounds

Several organic compounds have been synthesized, and their standard enthalpies of formation (\(\Delt

Medium

Designing an Experiment to Measure Reaction Enthalpy

You are tasked with designing an experiment using a calorimeter to measure the enthalpy change of a

Medium

Determining Enthalpy of Fusion of Ice

A student attempts to determine the enthalpy of fusion of ice using a simple calorimetry experiment.

Easy

Determining Reaction Enthalpy Using Standard Enthalpy of Formation

Methanol (CH$_3$OH) is formed according to the reaction: $$C(s) + \frac{1}{2}O_2(g) + 2H_2(g) \right

Hard

Determining Unknown Reaction Enthalpy Using Hess’s Law

Consider the following stepwise reactions: Reaction 1: $$A → B$$, ΔH = +40 kJ Reaction 2: $$B → C$$

Hard

Energy Changes and Molecular Stability

A series of reactions show different enthalpy changes. Consider a reaction where compound A has \(\D

Easy

Energy Diagram Analysis for Exothermic and Endothermic Reactions

A researcher provided energy diagrams for two reactions with different characteristics. The diagrams

Medium

Energy Diagram and Reaction Mechanism Analysis

An energy diagram of a two-step reaction shows: Step 1 with an activation energy of 50 kJ/mol leadin

Hard

Energy Transfer in Redox Reactions of Rechargeable Batteries

Redox reactions in rechargeable batteries involve energy transfer that can result in measurable heat

Hard

Enthalpy of Phase Change: Melting and Vaporization

An energy versus temperature diagram for a substance undergoing phase changes is provided. This diag

Medium

Enthalpy of Solution: Dissolution of an Ionic Compound

In a calorimetry experiment, 5.00 g of ammonium nitrate is dissolved in 100.0 g of water inside a ca

Medium

Heat Transfer in Everyday Systems

In an experiment, a researcher measured temperature changes in a container of water heated on a hot

Easy

Investigating Heat Transfer in Liquid Mixtures

A researcher performs an experiment by mixing 50.0 g of water at 80.0°C with 50.0 g of water at 20.0

Easy

Investigating the Enthalpy of Fusion via Calorimetry Experiment Design

The melting of a solid involves distinct energy changes as bonds are broken during the phase transit

Medium

Kinetic Energy and Heat Transfer

In this FRQ, consider the principles of kinetic energy related to temperature and explain how heat i

Easy

Kinetic Energy and Temperature in Gaseous Samples

A graph is provided showing how the average kinetic energy of gas molecules varies with temperature.

Easy

Phase Changes and Enthalpy Calculations

A 100 g sample of a substance is heated from a solid state through melting and then vaporization. Th

Medium

Real-World Application: Heat Transfer in Chemical Reactions

In certain laboratory reactions, observers note that a beaker can become noticeably hot during an ex

Easy

Study of Phase Transition: Quantifying Enthalpy of Fusion

An experiment was conducted to measure the enthalpy of fusion for a substance. A sample of Substance

Medium

Temperature Effects on Reaction Rates

Experimental data for a reaction are collected at different temperatures, as shown in the table belo

Extreme

Thermodynamics of Sublimation

Consider a substance with an enthalpy of sublimation given by $$ΔH_{sub} = 30.0\ kJ/mol$$. Answer th

Medium

Using Hess’s Law with Experimental Data

Experiments have been conducted to determine the enthalpy changes for two intermediate reactions tha

Hard
Unit 7: Equilibrium

Acid-Base Equilibria: Understanding Ka and Kb

For the weak acid HA, which dissociates as follows: $$HA \rightleftharpoons H⁺ + A⁻$$, the acid diss

Medium

Acid-Base Equilibrium and Ka Determination

A weak acid, HA, dissociates in water according to the equation $$HA \rightleftharpoons H^{+} + A^{-

Hard

Analysis of Reaction Mechanism in Multistep Equilibrium Reactions

A reaction proceeds via a two-step mechanism where a fast equilibrium is established followed by a s

Extreme

Analyzing Kp and Kc in Gas-Phase Equilibria

A researcher studies the gaseous reaction: $$2*X(g) + Y(g) ⇌ 3*Z(g)$$. Considering the relationship

Hard

Application of Hess's Law to Equilibrium Constant Manipulations

Consider the following reactions: Reaction 1: $$\text{A} \rightarrow \text{B}, \quad K_1 = 4.0$$ R

Hard

Application of Le Chatelier's Principle in Industrial Settings

The Haber process for ammonia production is represented as: $$N_2(g) + 3\,H_2(g) \rightleftharpoons

Medium

Applying Reaction Quotient Q in a Carbonate System

In an environmental study of carbonated water, the following equilibrium is considered: $$H_2CO_3 \r

Medium

Buffer Equilibrium and pH Measurement in Acetic Acid/Sodium Acetate System

A buffer solution is prepared by mixing acetic acid and sodium acetate. The pH is monitored and a gr

Medium

Comparative Analysis of $$K_{c}$$ and Reaction Quotient $$Q$$

For the reaction $$\mathrm{A + B \rightleftharpoons C + D}$$, consider that the system has reached e

Hard

Comparing Kc and Kp in Gas Equilibria

For the reaction: $$\ce{2*A (g) + B (g) <=> 3*C (g)}$$, answer the following:

Medium

Conceptual Understanding of Reaction Quotient (Q)

Clarify the significance of the reaction quotient (Q) in chemical equilibrium and how it compares to

Easy

Data Analysis of Equilibrium via Graphical Representation

A researcher monitored the concentration of a reactant R over time for the reaction $$\text{R} \left

Hard

Determining $$K_{c}$$ and $$K_{p}$$ from Experimental Data

The reaction under study is: $$\mathrm{2SO_2 (g) + O_2 (g) \rightleftharpoons 2SO_3 (g)}$$. Experime

Extreme

Determining Equilibrium from Reaction Conditions

An equilibrium for the reaction $$G + H \rightleftharpoons I + J$$ is established and experimental d

Medium

Determining Reaction Direction using Q and Keq

A reaction A + 2B ⇌ 3C is studied in the lab. The concentrations at a given moment are provided in t

Medium

Determining the Solubility Product of AgCl

A researcher investigates the solubility of silver chloride (AgCl) in water. AgCl dissolves accordin

Medium

Dilution Effects on Aqueous Equilibria

Consider the following equilibrium in an aqueous solution: $$Fe^{3+}(aq) + SCN^{-}(aq) \leftrighthar

Hard

Dilution Effects on Aqueous Equilibria

Investigate the impact of dilution on an aqueous equilibrium system.

Hard

Dynamic Equilibrium and Reaction Rate Graphs

A graph depicting forward and reverse reaction rates over time for the equilibrium reaction $$D (g)

Extreme

Dynamic Equilibrium and Reaction Rates

At equilibrium, a reaction exhibits constant concentrations due to balanced forward and reverse reac

Easy

Effect of Catalysts on Equilibrium and Reaction Rates

A reaction is catalyzed by an enzyme, which increases the rate at which equilibrium is reached witho

Easy

Environmental Solubility Equilibrium Error in Heavy Metal Salts

In an environmental study, a team investigates the solubility equilibrium of a heavy metal sulfate i

Extreme

Equilibrium Calculations in the Haber Process

Consider the Haber process: $$\mathrm{N_2 + 3*H_2 \rightleftharpoons 2*NH_3}$$. The system is initia

Medium

Equilibrium Constant Manipulations via Hess’s Law

Hess’s Law allows the manipulation of equilibrium constants for multi‐step reactions. Answer the fol

Extreme

Equilibrium Expression and Q Calculation

Consider the general equilibrium reaction: $$a*A + b*B \rightleftharpoons c*C + d*D$$. (a) Write the

Easy

Equilibrium Kinetics and Reaction Order

Consider a reversible reaction for which concentration data over time is provided in the attached gr

Extreme

Exothermic Reaction Equilibrium and Temperature Effects

For the reaction $$\text{X} + Y \leftrightharpoons Z + \text{heat}$$ (an exothermic process), answer

Medium

Experimental Design for Temperature Effect on Equilibrium

Design an experiment to investigate how temperature changes affect the equilibrium constant $$K_{eq}

Hard

Experimental Design: Determining Ksp of a Sparingly Soluble Salt

Design an experiment to determine the solubility product constant (Ksp) of a sparingly soluble salt

Hard

Experimental Determination of $$K_c$$ for HI Decomposition

Consider the decomposition of hydrogen iodide (HI): $$2HI (g) \rightleftharpoons H_2 (g) + I_2 (g)$$

Hard

Graph Analysis of Equilibrium Attainment

A graph depicting the concentration of reactants and products over time for a reversible reaction is

Hard

Graphical Analysis of Equilibrium Shifts

A reaction in a closed system exhibits varying concentrations over time. Analyze the provided graph

Medium

Haber Process Equilibrium Analysis

Examine the dynamic nature of the Haber process and analyze how chemical equilibrium is established

Medium

Haber Process Equilibrium Analysis

Consider the Haber process for the synthesis of ammonia: $$N_2 + 3*H_2 \leftrightarrow 2*NH_3$$, occ

Easy

Haber Process Equilibrium Error Analysis

In this experiment, a researcher studies the Haber process ($$N_2 + 3*H_2 \rightleftharpoons 2*NH_3$

Medium

Hess's Law and Equilibrium Constant Combination: Error Identification

A researcher seeks to determine the overall equilibrium constant for a composite reaction by combini

Medium

Impact of Reaction Coefficient Scaling on Equilibrium Constants

Consider the reversible reaction: $$2*A + 3*B ⇌ 4*C$$ with an equilibrium constant $$K$$. A research

Easy

Inert Gas Effects on Equilibrium

Consider a gaseous equilibrium system at equilibrium. Describe what happens when an inert gas is add

Medium

Ionization of Water, Kw, and pH Changes

Consider the ionization of water, described by the equilibrium $$H_2O(l) \leftrightarrow H^+(aq) + O

Medium

Kinetics of Equilibrium: Tracking the Reaction Quotient Over Time

A student monitors the progress of the reaction: $$D+E ⇌ F$$ over a period of 15 minutes and records

Medium

Kinetics vs Equilibrium in a Multi-step Reaction

In a multi-step reaction, individual steps have their own kinetic rates, yet the overall equilibrium

Extreme

Le Chatelier’s Principle: Pressure and Temperature Effects in the Haber Process

Evaluate and explain how changes in pressure and temperature affect the equilibrium position in the

Easy

Manipulating Equilibrium Constants via Reaction Combination

Given the two reactions: 1) $$A \leftrightarrow B$$ with equilibrium constant $$K_1$$, 2) $$B \leftr

Medium

Multi-step Equilibrium Manipulations

Combine multiple reactions by manipulating their equilibrium expressions to derive an overall equili

Hard

Multi-Step Reaction Equilibria Analysis

Consider a two-step reaction sequence given by: Step 1: $$A \rightleftharpoons B$$ with equilibrium

Extreme

Optimization Strategies in the Haber Process

Discuss various methods employed in industrial settings to maximize the yield of ammonia in the Habe

Medium

Oxygen Binding in Hemoglobin: An Equilibrium Perspective

Hemoglobin binds oxygen reversibly, and its binding equilibrium can be influenced by changes in carb

Hard

Quantitative Analysis of Reaction Quotient Q

In a study of the reaction $$X + Y \rightleftharpoons Z$$, initial concentrations are $$[X] = 0.6\,M

Medium

Reaction Quotient (Q) and Equilibrium Position

Analyze the reaction quotient (Q) relative to the equilibrium constant to predict the direction of a

Easy

Reaction Quotient (Q) Evaluation

For the reaction: $$N_2 (g) + 3*H_2 (g) \rightleftharpoons 2*NH_3 (g)$$, consider the initial concen

Medium

Solid Marker in Reaction Quotient Calculation Error

A researcher investigates the equilibrium for the reaction $$L(s) + M(aq) ⇌ N(aq)$$ by measuring the

Hard

Solubility Product and Common Ion Effect: Error Analysis

A researcher studies the solubility of AgCl by preparing solutions in pure water and in water contai

Hard

Solubility Trends and Temperature Effects

A salt’s solubility in water was experimentally measured at different temperatures, yielding the fol

Medium

Temperature Dependence in Endothermic vs. Exothermic Reactions

Two reactions, one exothermic and one endothermic, were studied over a temperature range. Data table

Medium

Temperature Effects on Equilibrium Constant

Consider an exothermic reaction at equilibrium represented by $$A + B \leftrightarrow C + D + \text{

Medium

Temperature Effects on Exothermic Equilibrium Reactions

Consider the exothermic ammonia synthesis reaction: $$\ce{N2 + 3*H2 <=> 2*NH3}$$ with $$\Delta H = -

Medium

Titration Error in Determining $$K_{sp}$$ of a Salt

A titration experiment is performed to determine the solubility product $$K_{sp}$$ for a sparingly s

Hard
Unit 8: Acids and Bases

Application of pH in Environmental Chemistry: Acid Rain Effects

Acid rain forms when atmospheric pollutants mix with water, lowering the pH of lakes and other natur

Medium

Behavior of Weak Acids: Percent Dissociation Analysis

A weak acid, HA, has a dissociation constant $$K_a = 1.8 \times 10^{-5}$$. Analyze its dissociation

Hard

Bloodstream Buffer Simulation

In the human body, the blood pH is tightly regulated around 7.4. A key contributor is a buffer syste

Easy

Buffer Capacity and Dilution Effects

A buffer system consisting of acetic acid and sodium acetate is under investigation to understand it

Medium

Buffer Capacity and pH Change

Three buffer solutions are prepared with the following compositions: Buffer A: 0.50 M acetic acid a

Hard

Buffer Design for Pharmaceutical Applications

In pharmaceutical formulations, maintaining a stable pH is critical. A formulation is designed to ha

Medium

Buffer pH Calculation

A buffer solution is prepared by mixing 0.20 M acetic acid (HC2H3O2) with 0.15 M sodium acetate (NaC

Medium

Buffer Response in a Weak Acid–Strong Base Titration

During the titration of a weak acid with a strong base, the solution exhibits a buffer region where

Medium

Buffer Solution Preparation Miscalculation

In an experiment, a student attempted to prepare a buffer solution by mixing 100 mL of 0.2 M acetic

Medium

Buffer System Design Using Acetic Acid and Sodium Acetate

A chemist wishes to prepare a buffer solution with a target pH of 4.76 using acetic acid (HC2H3O2) a

Medium

Calculating pOH and Linking to pH

In aqueous solutions, pH and pOH are related via water ionization. Use this relationship to solve th

Easy

Common Ion Effect Misinterpretation in Solubility

An experiment was conducted to determine the solubility of Mg(OH)₂ by dissolving it in solutions of

Medium

Common Ion Effect on the Solubility of Mg(OH)2

In a saturated solution of Mg(OH)2, the following equilibrium is established: $$Mg(OH)_2 (s) \rightl

Medium

Comparative Analysis of pH-Dependent Solubility

Compare the solubility of two hydroxide salts, $$Mg(OH)_2$$ and $$Ca(OH)_2$$, in solutions of varyin

Medium

Comparative Solubility Study of Metal Hydroxides Under Varying pH Conditions

The solubility of metal hydroxides is strongly pH-dependent. Address the following:

Extreme

Comparing Acidity between Oxoacids and Binary Acids

Discuss factors affecting the acid strengths of oxoacids versus binary acids. Answer the following:

Medium

Critically Evaluating Chemical Equilibrium in Acid–Base Neutralizations

A published study suggests that product formation in an acid–base neutralization reaction is indepen

Extreme

Designing a Titration Laboratory Experiment for a Weak Acid

A researcher is tasked with designing a titration experiment to determine the concentration of a wea

Medium

Determining pH in Acid Solutions

In an aqueous solution of a strong acid, the pH is determined by the concentration of hydrogen ions

Easy

Effect of Temperature on Water Ionization (Kw)

At 25°C, the ion product of water is $$K_w = 1 \times 10^{-14}$$. Explain how an increase in tempera

Hard

Evaluating Acid Strength via pKa and Percent Dissociation

A researcher investigates several weak acids to determine their strengths. Analyze the relationship

Medium

Impact of Common Ion Effect on Salt Solubility

A student is investigating the solubility of calcium hydroxide (Ca(OH)₂) in solutions with high conc

Medium

Impact of pH on Solubility of Mg(OH)2

This FRQ investigates how solution pH affects the solubility of the sparingly soluble hydroxide salt

Medium

Indicator Color Change and pH Transition Range

Indicators are weak acids whose color changes with pH. Analyze their role in acid–base titrations.

Easy

Indicator Selection for a Neutralization Titration

During a titration experiment, an appropriate indicator must be chosen to accurately signal the endp

Medium

Misinterpretation of Neutralization Endpoints in Mixed Acid Systems

A student performed a titration on a solution containing a mixture of HCl (a strong acid) and acetic

Hard

Neutralization Reaction Analysis for Weak Acid-Strong Base Titration

In a titration experiment, acetic acid (a weak acid with $$pK_a = 4.76$$) is titrated with a strong

Hard

Neutralization Reaction in a Weak Acid-Strong Base System

A lab experiment investigates the titration of acetic acid (HC2H3O2) with sodium hydroxide (NaOH) in

Medium

pH Calculation of Strong Acid

A 0.010 M HCl solution is prepared. Use the expression $$pH = -\log([H^+])$$ to calculate the pH of

Easy

pH Impact on Solubility of a Sparingly Soluble Base

The solubility of sparingly soluble hydroxide salts depends on the solution pH. A researcher is stud

Hard

pOH Calculation and Its Relationship to pH

A solution of 0.0010 M NaOH is prepared. (a) Calculate the pOH of this solution using $$pOH = -\lo

Medium

Polyprotic Acid Titration and Stepwise Dissociation

Phosphoric acid (H3PO4) is a polyprotic acid that dissociates in three steps with the dissociation c

Hard

Polyprotic Acid Titration: Misinterpretation of Stepwise Dissociation

In an experiment involving the titration of phosphoric acid (H₃PO₄) with a strong base, a student as

Hard

Relationship Between Molecular Structure and Acid Strength

Compare the acid strength of hydrogen fluoride (HF) with that of hydrochloric acid (HCl) and analyze

Extreme

Stoichiometric Analysis of Neutralization

A solution containing 0.04 mol of HCl is mixed with 0.03 mol of NaOH, and the final volume of the so

Medium

Water Ionization and Temperature Effects

This question explores the ionization of water and the effect of temperature changes on the ion prod

Easy
Unit 9: Applications of Thermodynamics

Calculating Standard Cell Potential from Half-Reactions

Two half-reactions are provided with their standard reduction potentials. Half-reaction 1 is $$\ce{C

Medium

Comparative Analysis of Gibbs Free Energy Change Determinations

A student calculates $$\Delta G^\circ$$ in two ways: (1) using $$\Delta G^\circ = -RT\ln K$$ and (2)

Hard

Designing a Multi-step Redox Reaction Experiment

A researcher aims to investigate a multi-step redox reaction that involves an intermediate species.

Extreme

Determination of Equilibrium Constant from Gibbs Free Energy

A study claims that the equilibrium constant (K) for a reaction can be directly calculated using the

Hard

Effect of Temperature on Gibbs Free Energy: Data Analysis

An experiment records the variation in Gibbs free energy (\(\Delta G\)) of a reaction with temperatu

Medium

Electrode Potential Measurements Under Non-Ideal Conditions

A student performed an experiment to measure the cell potential of a galvanic cell constructed with

Easy

Electroplating Efficiency and Calculations

Electroplating is a common industrial application of electrolytic cells. Analyze the process with th

Hard

Energy Output Calculation for a Galvanic Cell in a Remote Sensor

A galvanic cell powers a remote sensor with a constant cell potential of $$1.50\,V$$ and a continuou

Medium

Entropy Change in Reaction Systems

In an experiment, an ideal gas‐phase reaction converts 1 mole of A(g) into 1 mole of B(g) and 1 mole

Easy

Entropy Changes in Phase Transitions

The table below lists various phase transitions along with their respective entropy changes (ΔS). An

Easy

FRQ 1: Calculating Standard Entropy Change

A reaction involving nitrogen dioxide and dinitrogen tetroxide is given by the equation: $$2\,NO_2(g

Easy

FRQ 20: Reaction Mechanism Investigation Using Gibbs Free Energy

A multi-step reaction mechanism is proposed for the conversion of reactant A to product D. The mecha

Extreme

Investigating Non-Standard Conditions in Galvanic Cells

A chemist monitors the voltage of a galvanic cell under non‐standard conditions over time. The follo

Hard

Pressure Effects on Gibbs Free Energy

In gas-phase reactions, pressure changes can influence the Gibbs free energy. Consider a reaction th

Hard

Reduction Potentials and Gibbs Free Energy Calculation

Consider a redox reaction with a standard cell potential given by \(E° = 0.80 \text{ V}\).

Easy

Temperature Dependence of Gibbs Free Energy

For a reaction described by the equation $$\Delta G° = \Delta H° - T\Delta S°$$, analyze how tempera

Hard

Thermodynamic Analysis of a Complex Reaction

A complex reaction is studied under varying conditions to understand the interplay between enthalpy,

Extreme

Unit Conversion in Gibbs Free Energy Calculations

A reaction has \(\Delta H° = -100 \text{ kJ/mol}\) and \(\Delta S° = -210 \text{ J/mol·K}\) at 298 K

Easy

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Where can I find practice free response questions for the AP Chemistry exam?
The free response section of each AP exam varies slightly, so you’ll definitely want to practice that before stepping into that exam room. Here are some free places to find practice FRQs :
  • Of course, make sure to run through College Board's past FRQ questions!
  • Once you’re done with those go through all the questions in the AP ChemistryFree Response Room. You can answer the question and have it grade you against the rubric so you know exactly where to improve.
  • Reddit it also a great place to find AP free response questions that other students may have access to.
How do I practice for AP AP Chemistry Exam FRQs?
Once you’re done reviewing your study guides, find and bookmark all the free response questions you can find. The question above has some good places to look! while you’re going through them, simulate exam conditions by setting a timer that matches the time allowed on the actual exam. Time management is going to help you answer the FRQs on the real exam concisely when you’re in that time crunch.
What are some tips for AP Chemistry free response questions?
Before you start writing out your response, take a few minutes to outline the key points you want to make sure to touch on. This may seem like a waste of time, but it’s very helpful in making sure your response effectively addresses all the parts of the question. Once you do your practice free response questions, compare them to scoring guidelines and sample responses to identify areas for improvement. When you do the free response practice on the AP Chemistry Free Response Room, there’s an option to let it grade your response against the rubric and tell you exactly what you need to study more.
How do I answer AP Chemistry free-response questions?
Answering AP Chemistry free response questions the right way is all about practice! As you go through the AP AP Chemistry Free Response Room, treat it like a real exam and approach it this way so you stay calm during the actual exam. When you first see the question, take some time to process exactly what it’s asking. Make sure to also read through all the sub-parts in the question and re-read the main prompt, making sure to circle and underline any key information. This will help you allocate your time properly and also make sure you are hitting all the parts of the question. Before you answer each question, note down the key points you want to hit and evidence you want to use (where applicable). Once you have the skeleton of your response, writing it out will be quick, plus you won’t make any silly mistake in a rush and forget something important.