AP Chemistry FRQ Room

Atomic Radii and Crystallographic Trends

Interpret experimental data on atomic radii and discuss underlying causes and measurement challenges

Combustion Analysis for Empirical Formula Determination with Calculation Misinterpretation

A student performs a combustion analysis to determine the empirical formula of an unknown organic co

Designing an Experiment to Determine Molarity

Outline a methodology to determine the molarity of an unknown sodium chloride (NaCl) solution using

Determination of Empirical Formula from Combustion Analysis

A compound consisting only of carbon, hydrogen, and oxygen is analyzed by combustion. The combustion

Effects of Electron Shielding on Ionization Energy

A graph plotting ionization energy versus atomic number across a period displays an overall increasi

Electron Configuration and Periodic Trends

Consider the electron configurations of elements across a period and the resulting periodic trends.

Electron Configuration Determination from Spectroscopic Data

A spectroscopic study of unknown elements reveals several emission lines corresponding to electron t

Electron Configuration Determination via Photoelectron Spectroscopy

Photoelectron spectroscopy (PES) is used to probe the energies of electrons in an atom, providing in

Electron Configuration Diagram Analysis

Given the electron configuration diagram for elements in the third period, identify the element with

Energy Level Transitions and Emission Spectra

When an electron in an atom transitions from a higher energy level to a lower one, it emits electrom

Exploring Molarity and Reaction Stoichiometry

In a titration experiment, 25.0 mL of 0.10 M hydrochloric acid (HCl) is titrated with 0.10 M sodium

Gas Evolution Reaction: Mole Calculations Using the Ideal Gas Law

During a chemical reaction, a gas is produced and collected over water. After correcting for water v

Gas Law and Mole Calculations in Reaction Conditions

A reaction in a closed container produces an ideal gas. At 298 K, 1 atm, and a volume of 11.2 L, ans

Ideal Gas Law and Mole Determination

An unknown gas is studied at STP. The following experimental data were recorded: Volume = $$22.4$$ L

Impact of Electron Shielding on Ionization Energy

Discuss how electron shielding affects the ionization energy of elements. Compare the ionization ene

Ionic Charge Prediction and Compound Formation

Using periodic trends and the octet rule, answer the following: (a) Predict the ionic charges for ma

Isotopic Abundance and Atomic Mass Determination

Element X has two naturally occurring isotopes with the following data: Isotope A: 35 amu (75% abund

Le Chatelier’s Principle in Industrial Equilibrium

Consider an industrial equilibrium reaction involving gaseous reactants and products. The graph prov

Mole-to-Gram Conversion and Percent Yield Calculation

In an experiment, 10.0 g of reactant A was used and the reaction was expected to produce 15.0 g of p

Molecular Geometry and VSEPR Theory

Using VSEPR theory, determine the molecular geometry of SF₄ and explain how the presence of lone pai

Percent Composition and Empirical Formula Determination

A compound is analyzed and found to have the following percent composition by mass: $$40.0\%$$ carbo

Percent Composition and Stoichiometry

In an environmental analysis, a compound is found in a mineral with a mass composition of 40% metal

Percent Composition of Calcium Nitrate

Calculate the percent composition of each element in calcium nitrate, $$Ca(NO_3)_2$$. Use the follow

Periodic Trends: Atomic Radius and Ionization Energy

Analyze the trends in atomic radius and ionization energy as you move across a period and down a gro

Periodic Trends: Atomic Radius, Ionization Energy, and Electronegativity

Examine the periodic trends as elements are arranged in periods and groups. A graph showing trends f

Shielding Effect and Ionization Energies

Electron shielding influences the effective nuclear charge experienced by outer electrons. Answer th

Stoichiometry of a Chemical Reaction

Consider the reaction: $$2 * A + 3 * B \to C$$. Answer the following:

Titration Experiment for Unknown Acid Molarity Determination

Titration is a common method for determining the molarity of an unknown acid solution. Design an exp

Understanding the Bohr Model and Energy Absorption

This question examines the application of the Bohr model to determine energy differences between ele

Analysis of Network Covalent Solids vs. Molecular Solids

This question asks you to compare the distinctive physical properties of network covalent solids and

Analyzing Alloy Composition and Properties

An engineering lab is analyzing an alloy sample suspected to be brass to understand how alloy compos

Bond Energetics: Reaction Energy Analysis

Analyze a reaction based on bond dissociation and formation energies to determine the net energy cha

Catalysis in Covalent Bond Formation Kinetics

A student investigates the role of a catalyst in a covalent bond-forming reaction by conducting para

Comparative Conductivity Analysis

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

Conductivity and Bonding Type Analysis in Solutions

A student investigates the electrical conductivity of various substances in different phases. The ta

Determining Molecular Polarity from Lewis Structures

Using the molecular geometry and Lewis structure of carbon dioxide ($$CO_2$$), determine its polarit

Electronegativity and Bond Polarity

A chemist is examining various diatomic molecules to determine how differences in electronegativity

Expanded Octets and Bonding in SF6

Examine the bonding in sulfur hexafluoride ($$SF_6$$) with a focus on expanded octets and formal cha

FRQ 6: Ionic Solutions – Conductivity and Concentration

A table shows the electrical conductivity of aqueous solutions of NaCl and CaCl₂ at different molar

FRQ 19: Analyzing Experimental Data on Bond Order and Bond Length

A graph plotting bond order versus bond length for a series of molecules is provided. In your answer

Investigating Ionic Conduction in Aqueous Solutions

A chemist is studying the electrical conductivity of aqueous solutions of ionic compounds. Two salts

Ionic Lattice Energies and Melting Points

A researcher investigates how ionic charge and ionic radii affect the lattice energy and melting poi

Ionic Lattice Energy and Coulomb's Law Application

This question requires you to apply Coulomb's Law to explain the factors affecting ionic lattice ene

Lewis Dot Structure of the Sulfate Ion

For the sulfate ion $$SO_{4}^{2-}$$, use your knowledge of Lewis dot structures and formal charge ca

Metallic Bonding and Electron Mobility

Discuss the nature of metallic bonding and its contribution to electrical conductivity in metals and

Phase-dependent Conductivity of Ionic and Covalent Compounds

This question explores how the physical state of a substance influences its electrical conductivity,

Properties of Network Covalent Solids

Discuss how the continuous network of covalent bonds in network covalent solids leads to their uniqu

Analysis of Contact Angle Measurements and Intermolecular Forces

A student performs an experiment to study how intermolecular forces influence the behavior of liquid

Application of the Ideal Gas Law Under Non-Ideal Conditions

A student performs an experiment to study the behavior of a gas by applying the ideal gas law, $$PV

Charles' Law and Volume Change with Temperature

The combined gas law explains how gas volume changes with temperature. Use Charles' law for a calcul

Chromatographic Separation of Mixtures

Apply principles of paper chromatography to separate a dye mixture and interpret the data to determi

Chromatographic Separation Techniques

Compare various chromatographic techniques for separating mixtures and design an experiment for comp

Chromatography and Polarity Separation

A researcher employs paper chromatography to separate dyes from an ink sample. The movement of each

Chromatography: Analyzing Retention Factors in Separation

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

Coulombic Attraction and Lattice Energy

Use ionic data to analyze lattice energies and explain how Coulombic attractions influence the physi

Coulombic Attraction and Lattice Energy Analysis

A solid ionic compound is being analyzed to understand the role of Coulombic attraction in its latti

Coulombic Forces in Ionic versus Covalent Bonds and Phases

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

Dalton's Law of Partial Pressures

Examine Dalton's law and its application to gas mixtures.

Designing a Paper Chromatography Experiment to Analyze Ink Composition

A student intends to separate the components of a complex black ink using paper chromatography. The

Determining Density and Molar Mass of an Unknown Gas

A student is tasked with determining the density of an unknown gas and calculating its molar mass us

Determining Gas Molar Mass from Density

The density of a gas can be used to determine its molar mass by the equation $$MM = \frac{D*R*T}{P}$

Effects of Temperature and Molar Mass on Effusion Rates

Examine the data on effusion times to analyze the combined effects of temperature and molar mass on

Effusion and Gas Kinetics

A researcher is studying the effusion rates of hydrogen and oxygen gases as well as their respective

Effusion Rates and Molecular Mass Relationship

Using the experimental data on gas effusion, analyze how molar mass affects the rate of effusion.

Electronegativity and Bonding

Evaluate the role of electronegativity differences in determining bond polarity and molecular struct

Gas Effusion and Molar Mass Determination

Effusion, the escape of gas molecules through small openings, provides insight into molar mass diffe

Intermolecular Forces and Boiling Points Investigation

A researcher evaluated the boiling points of four compounds with different intermolecular forces, us

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

London Dispersion Forces Evaluation

This question examines the nature of London dispersion forces (LDFs) in comparison to dipole-dipole

Molecular Polarity Analysis

A chemist is investigating how molecular geometry influences molecular polarity using the molecules

Molecular Polarity Analysis

A researcher examines covalent molecules to determine their overall polarity. Using the provided tab

Molecular Polarity and Dipole Moment Estimation

Consider the molecules carbon tetrafluoride (CF4) and nitrogen trifluoride (NF3). Although both have

Solvent-Solute Interactions and Dissolution

This question explores the concept of solvent-solute interactions in the context of dissolution, emp

Acid-Base Equilibria and Conjugate Pairs

A researcher investigates the equilibrium behavior of acetic acid in aqueous solution to understand

Acid-Base Equilibrium of Acetic Acid

Acetic acid reacts with water according to the equilibrium: $$HC_2H_3O_2 + H_2O \rightleftharpoons C

Acid-Base Neutralization Reaction and pH Calculation

In a titration experiment, 50.00 mL of 0.100 M acetic acid (HC2H3O2) is neutralized with 0.100 M NaO

Acid-Base Reaction Efficiency Analysis

A series of experiments were conducted to study the efficiency of acid-base neutralization reactions

Acid-Base Reaction Kinetics: Neutralization Reaction Rate

Acid-base neutralization reactions are fundamental in chemistry. Design an experiment to investigate

Balancing Chemical Equations and Stoichiometric Calculations

A researcher is practicing balancing chemical equations and using them to perform stoichiometric cal

Balancing Half-Reactions in Redox Processes

In the context of redox reactions, several proposed half-reactions for the oxidation of iron (Fe) ar

Combustion Analysis of a Hydrocarbon

A 1.00 g sample of a hydrocarbon with formula $$C_xH_y$$ is completely combusted. The combustion pro

Combustion Analysis of Butane

Butane ($$C_4H_{10}$$) combusts in oxygen to produce carbon dioxide and water.

Comparative Analysis of Reaction Types

A researcher investigates several reaction types including synthesis, decomposition, redox, and prec

Comprehensive Combustion Analysis of Hydrocarbon Samples

A researcher conducts a combustion analysis of a hydrocarbon sample to determine its empirical formu

Decomposition Reaction Analysis

A decomposition reaction following the form AB → A + B was studied at various temperatures. The foll

Determining the Rate Law from a Reaction Mechanism

A reaction is proposed to occur via a two-step mechanism. The slow, rate-determining step is: $$A +

Electron Transfer in Copper Deposition

Examine the half-reaction: $$Cu^{2+} (aq) + 2*e^{-} \rightarrow Cu (s)$$. Answer the following:

Experimental Analysis of Percent Error in Chemical Reactions

In an experiment, the theoretical yield of a reaction product is 25.0 g while the experimental yield

Experimental Design: Effect of Concentration on Redox Kinetics

A research laboratory is investigating how the concentration of reactants affects the rate of a redo

FRQ 1: Reaction Type Analysis and Equation Balancing

A researcher claims that the reaction $$A+B \rightarrow AB$$ is a synthesis reaction. Using the prov

FRQ 9: Temperature Effects on Decomposition Reactions

An experiment investigates the decomposition reaction $$AB \rightarrow A + B$$ at different temperat

FRQ 10: Analysis of Percent Error in Calorimetry

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

FRQ 17: Combustion Analysis and Environmental Impact

A study compares the combustion of a hydrocarbon under complete and incomplete conditions. Complete

Gravimetric Analysis: Determination of Alkali Metal in a Hydroxide Sample

An unknown alkali hydroxide is analyzed by dissolving a 4.33 g sample and reacting it with copper (I

Gravimetric Analysis: Identification of a Metal Ion via Precipitation

An unknown solution containing a trivalent metal ion \(M^{3+}\) is treated with a base to precipitat

Hydrocarbon Combustion: Stoichiometry and Calculation

A 10.00 g sample of an unknown hydrocarbon, represented as $$C_xH_y$$, is completely combusted in ex

Inquiry into Reaction Types in the Laboratory

A researcher is investigating different classes of chemical reactions by setting up experiments to d

Integrated Analysis of Water Treatment Process

A water treatment facility uses a multi-step process to remove iron contaminants from water. The pro

Integrated Reaction Design: Combining Acid-Base and Redox Steps

A researcher is developing a synthetic route that involves an acid-base neutralization to generate a

Multistep Reaction Mechanism Analysis

Consider a reaction mechanism where compound X first undergoes a synthesis reaction to form an inter

Percent Error in Experimental Reaction Yields

In a lab synthesis of compound AB, the theoretical yield was calculated to be 15.0 g, but the actual

Polymer Chemistry: Reaction Mechanisms in Polymerization

Polyethylene is produced by the radical polymerization of ethene (C2H4) under high pressure and temp

Precipitate Stability: Effect of pH on Solubility of Copper Hydroxide

The solubility of $$Cu(OH)_2$$ is highly dependent on the pH of the solution. Design an experiment t

Precipitation Reaction and Solubility Analysis

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

Precipitation Reaction and Solubility Rules

A 50.0 mL solution of 0.50 M AgNO3 is mixed with 50.0 mL of 0.50 M NaCl in a 100.0 mL container. A p

Reaction Mechanism Elucidation Using Half-Reaction Method

Elucidating reaction mechanisms in redox processes often involves analyzing half-reactions separatel

Redox Titration with Permanganate

In a redox titration, potassium permanganate ($$KMnO_4$$) is used to titrate a solution containing o

Synthesis Reaction and Stoichiometric Calculations

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

Synthesis Reaction for a Complex Salt

A laboratory procedure is designed to synthesize a complex salt by reacting a metal oxide with a car

Writing and Balancing Redox Reactions

Consider the unbalanced redox reaction: $$Fe + HCl \rightarrow FeCl_2 + H_2$$.

Analysis of Competing Reaction Pathways

A reaction can proceed via two parallel pathways. Pathway 1 is first order with respect to reactant

Analysis of First Order Kinetics Through Graphical Methods

A plot of $$\ln[A]$$ versus time for a reaction is provided below. (a) Determine the rate constant

Analysis of Zero-Order Reaction Kinetics

In a particular zero order reaction, the concentration of reactant A decreases linearly with time. U

Arrhenius Equation and Temperature Dependence

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

Comparing Integrated Rate Law Plots

The integrated rate laws for zero, first, and second order reactions can be determined by appropriat

Derivation of Overall Rate Law for a Pre-Equilibrium Mechanism

Consider the following mechanism: Step I (fast equilibrium): $$A + B \rightleftharpoons C$$ with eq

Designing a Kinetic Experiment: Second-Order Reactions

A chemist is designing an experiment to determine the kinetic parameters of a new reaction suspected

Designing Experiments to Determine Reaction Order

A researcher wants to determine the order of reaction for the decomposition of compound X. The exper

Determining Half-Life from Kinetic Data

A reaction is monitored over time and the concentration of reactant A is recorded. Use the data to d

Determining Rate Law from Initial Concentration Data

Consider the reaction A + 2B + C → D. A series of experiments were performed with different initial

Determining Reaction Order from Time-Dependent Data

In an experiment, the concentration of reactant A was measured over time, yielding the following dat

Distinguishing Types of Enzyme Inhibition

A biochemical reaction is studied under different conditions, yielding the following kinetic paramet

Evaluating Methods to Determine Reaction Kinetics

Two distinct methods for determining reaction kinetics are employed: (1) the method of initial rates

Graph Interpretation of Competing Reaction Pathways

Two parallel reaction pathways convert reactant A into different products. The concentration of A is

Graphical Analysis of First-Order Kinetics

For a first-order reaction, the integrated rate law is given by $$\ln[A] = -k*t + \ln[A]_0$$. A grap

Graphical Determination of Half-Life for a First-Order Reaction

A first-order decomposition reaction was monitored, and the concentration of reactant A was measured

Graphical Determination of Half-Life for First Order Reactions

The half-life of a first order reaction is constant and can be determined from a plot of $$ln[A]$$ v

Initial Rate Method with Multiple Reactants

For the reaction $$A + B \to C$$, the following data (obtained using the initial rate method) were r

Investigating Half-Life in First-Order Reactions

A research team monitored a first-order reaction by recording the concentration of reactant A over t

Kinetic Isotope Effect Analysis

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

Reaction Inhibition and Kinetic Analysis

In the unimolecular reaction $$A \to B$$, the addition of an inhibitor I is found to decrease the re

Stirring Effects in Heterogeneous Reaction Kinetics

In a heterogeneous reaction where a solid catalyst is present in a solution, experiments were perfor

Temperature Dependence and the Arrhenius Equation

Temperature significantly influences reaction rates. Consider the following aspects of the Arrhenius

Zero Order Reaction Kinetics from Concentration vs. Time Data

A reaction is experimentally determined to be zero order with respect to reactant A. The concentrati

Zero-Order Reaction Kinetics

A particular reaction exhibits zero-order kinetics with respect to reactant A, meaning its rate is c

Application of Hess's Law in a Multi-step Reaction

A researcher is studying a reaction with overall equation $$X + Y \rightarrow Z$$. The reaction is b

Applying the First Law of Thermodynamics in a Closed System

An experiment in a closed system provided the following data: | Parameter | Valu

Calculating Reaction Enthalpy Using Bond Energies

Consider the reaction in which diatomic molecules A2 and B2 react to form 2 molecules of compound AB

Calculating Reaction Enthalpy Using Enthalpy of Formation

Given the following standard enthalpy of formation (ΔHf°) data: | Substance | ΔHf° (kJ/mol) | |----

Calculating Reaction Enthalpy Using Hess's Law

A multi-step reaction is analyzed to determine its overall enthalpy change. The following reactions

Calorimetry Experiment Analysis

A student uses a calorimeter to measure the heat released during an exothermic reaction in water. Th

Calorimetry Experiment on Heat Transfer in an Exothermic Reaction

A researcher investigates an exothermic reaction using a well‐insulated calorimeter. In the experime

Calorimetry in Action

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

Determining Enthalpy of Formation Experiment Design

Enthalpy of formation, $$\Delta H_f^\circ$$, represents the energy change when one mole of a compoun

Determining Unknown Reaction Enthalpy Using Hess’s Law

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

Effect of a Catalyst on Reaction Energy Diagram

An energy diagram is provided for a chemical reaction conducted both with and without a catalyst. Th

Effect of Catalyst on Activation Energy

A researcher claims that adding a catalyst significantly reduces the activation energy of a reaction

Energy Diagrams and Reaction Enthalpy

A researcher is studying a reaction's energy diagram for an exothermic process. The provided graph s

Experimental Investigation of Phase Change Thermodynamics

A researcher studies the melting of ice. Starting with 20.0 g of ice at -5°C, the substance is heate

Formation of Methanol and Enthalpy of Formation Analysis

Consider the reaction for the formation of methanol: $$C(s) + \frac{1}{2} O_2(g) + 2 H_2(g) \rightar

Interpreting a Phase Change Calorimetry Graph

Examine the attached graph showing temperature versus heat added for a substance undergoing a phase

Kinetic Energy and Temperature in Gaseous Samples

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

Measuring the Enthalpy of Sublimation

Sublimation involves the transition of a substance directly from the solid phase to the gas phase, a

Modeling the Heat Transfer in Industrial Processes

An industrial reactor designed for a chemical process experiences significant heat loss, affecting o

Molecular Kinetics and Reaction Energy Transfer

During a chemical reaction, observations indicate changes in the kinetic energy distribution of mole

Real-World Application: Heat Transfer in Chemical Reactions

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

Specific Heat Capacity and Heat Transfer in Everyday Materials

In an experiment, the temperature change of water and a metal cup were recorded under identical heat

Study of Endothermic Dissolution Processes

An ionic salt dissolves in water through a multi-step process: Step 1: Breaking the ionic lattice (Δ

Thermodynamic Analysis of Bond Formation and Breaking

A chemical reaction involves breaking bonds in the reactants and forming bonds in the products. If t

Using Hess's Law to Determine Enthalpy Change

A reaction between A and B to form C is difficult to measure directly. Instead, the reaction is carr

Using Hess’s Law with Experimental Data

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

Acid Dissociation and pH Variations in Weak Acid Solutions

An investigation on the dissociation of a weak acid, HA, measured the pH of solutions with varying i

Acid Dissociation Constant (Ka) Determination: Ionic Strength Oversight

In an experiment to measure the acid dissociation constant (Ka) for acetic acid, a researcher prepar

Analyzing Concentration vs. Time Graph for an Equilibrium Reaction

A researcher monitors the concentration of a product over time until equilibrium is reached. Answer

Assessing Claims on Pressure Effects and Equilibrium Constant

A recent media report claims that increasing the volume of a reaction vessel (or decreasing pressure

Calculating Keq for the Haber Process

In the Haber Process, the production of ammonia is governed by the reaction $$\text{N}_2 + 3*\text{H

Calculating Q and Predicting Equilibrium Shift

For the reaction $$P \rightleftharpoons Q$$, the equilibrium constant, $$K_{eq}$$, is 20. (a) Write

Combining Reactions and the Equilibrium Constant

Two reversible reactions were studied: Reaction 1: A ⇌ B with $$K_{eq1} = 4.0$$, and Reaction 2: B ⇌

Common Ion Effect on AgCl Solubility

Consider the solubility equilibrium of silver chloride (AgCl): $$AgCl (s) \rightleftharpoons Ag^+ (a

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

Comparison of Equilibrium Constants: Kc, Kp, and Ksp

Define and compare the equilibrium constants $$K_c$$, $$K_p$$, and $$K_{sp}$$.

Constructing and Using an ICE Table for Equilibrium Calculations

Use an ICE table to determine the equilibrium concentration of a weak acid in aqueous solution.

Deriving Kp from Kc for a Gaseous Reaction

Consider the gaseous reaction: $$2NO_2(g) \leftrightarrow N_2O_4(g)$$.

Designing an Experiment on Temperature and Pressure Effects on Equilibrium

You are tasked with designing an experiment to investigate the effects of temperature and pressure o

Designing an Experiment to Measure $$K_{eq}$$

A researcher aims to determine the equilibrium constant for the reaction: $$SO_2(g) + \frac{1}{2}O_

Dilution Effects on Aqueous Equilibria

Investigate the impact of dilution on an aqueous equilibrium system.

Dilution Effects on Equilibrium in Aqueous Solutions

The equilibrium reaction $$Fe^{3+}(aq) + SCN⁻(aq) \rightleftharpoons FeSCN^{2+}(aq)$$ is monitored u

Dilution Misconception in Weak Acid Equilibrium

A researcher investigates the ionization equilibrium of a weak acid, HA, in water by diluting a stoc

Effect of Dilution on Aqueous Equilibria

Investigate how dilution (adding water) affects the position of equilibrium in aqueous systems.

Effect of Dilution on Chemical Equilibrium

An experiment investigates the equilibrium reaction $$P(aq) + Q(aq) \rightleftharpoons R(aq)$$ to de

Environmental Chemistry and Solubility Equilibria

Examine the solubility equilibrium of lead(II) chloride in groundwater, represented by $$PbCl_2(s) \

Equilibrium Constant Manipulations

For a given reaction, changes in the reaction equation can affect the equilibrium constant. Answer t

Equilibrium Data Analysis in a Laboratory Experiment

In a lab experiment, the following data were collected for the reaction $$Fe^{3+}(aq) + SCN^-(aq) \l

Equilibrium in Consecutive Reactions and Intermediate Formation

Consider the following two consecutive reversible reactions: Reaction (1): $$A \rightleftharpoons I

Esterification Equilibrium: Misconception on the Role of Water

A researcher studies the esterification reaction $$CH_3COOH + C_2H_5OH \rightleftharpoons CH_3COOC_2

Esters Formation Equilibrium Error due to Reactant Excess

An experiment studies the esterification reaction between an alcohol and a carboxylic acid to form a

Evaluating Reaction Direction Using Reaction Quotient (Q)

Design an experiment to evaluate the reaction direction during the conversion of sulfur dioxide to s

Exploring the Common Ion Effect on Solubility

Design an experiment to investigate the effect of adding a common ion on the solubility of $$AgCl$$,

Haber Process Equilibrium Analysis

In the Haber process, $$N_2 + 3*H_2 \rightleftharpoons 2*NH_3$$, researchers study the equilibrium s

Haber Process Equilibrium Analysis

Consider the ammonia synthesis reaction: $$\ce{N2 + 3*H2 <=> 2*NH3}$$. Answer the following question

Heterogeneous Equilibrium Analysis

Consider the following equilibrium involving a solid and a gas: $$CaCO_3(s) \rightleftharpoons CaO(s

Industrial Application of Equilibrium in Sulfuric Acid Synthesis

The contact process is used for the industrial synthesis of sulfuric acid, involving the conversion

Industrial Equilibrium: The Contact Process for Sulfuric Acid Production

Examine the Contact Process for sulfuric acid production represented by the reaction $$2*SO_2 (g) +

Industrial Synthesis Equilibria: Optimization in the Haber Process

The Haber process for ammonia synthesis is given by $$N_2 (g) + 3*H_2 (g) \rightleftharpoons 2*NH_3

Kinetics to Equilibrium: Temperature Effects

A series of experiments were conducted on the gaseous reaction: $$J (g) + K (g) \rightleftharpoons L

Le Chatelier's Temperature Shift Error in Exothermic Reaction

A student studies the equilibrium for the exothermic reaction $$I + J ⇌ K + energy$$ by varying the

Manipulating Combined Equilibria

Two reversible reactions are given with their equilibrium constants as shown in the table. Use this

Photochemical Equilibrium in Iodine Dissociation: Error Analysis

A researcher studies the photodissociation equilibrium of iodine given by the reaction $$I_2 \rightl

Predicting Equilibrium Shifts in Industrial Processes

Consider the industrial gas-phase reaction: $$A(g) + 2*B(g) \leftrightarrow C(g) + D(g)$$. Answer th

Predicting Shifts in Complex Ion Formation Equilibria

Consider the complex ion formation equilibrium: $$\ce{Cu^{2+} (aq) + 4NH3 (aq) <=> [Cu(NH3)_4]^{2+}

Reaction Quotient and Equilibrium Prediction

For the reaction $$2*A \leftrightarrow B + C$$, initial concentrations are provided in the table bel

Reaction Quotient and Equilibrium Shift

For the reaction $$A_2 + 2*B \leftrightarrow 3*C$$, the measured concentrations at a given time are:

Reaction Quotient and Equilibrium Shift Determination

For the reaction $$\mathrm{2A \rightleftharpoons B + C}$$, the initial concentrations are provided i

Reaction Quotient and Precipitation Prediction

For the precipitation reaction $$CaF_2(s) \leftrightarrow Ca^{2+}(aq) + 2F^-(aq)$$ with $$K_{sp} = 3

Reaction Quotient Misinterpretation in Gas Phase Reaction

In a gas-phase reaction represented by $$X ⇌ Y$$, a research group monitors the system by measuring

Solubility and the Common Ion Effect

Investigate the dissolution of AgCl and the influence of the common ion effect. Answer the following

Solubility Changes with Temperature: An Experimental Analysis

A series of experiments measured the solubility of a sparingly soluble salt at various temperatures.

Temperature Effects on Equilibrium Constant

Discuss how an increase in temperature would affect the equilibrium constant $$K_{eq}$$ for the exot

Temperature Influence on Equilibrium in Exothermic Reaction

An exothermic reaction is studied over a range of temperatures, and the equilibrium constant is meas

Understanding Equilibrium in Reactions Involving Solids and Gases

Examine the equilibrium reaction: $$CaCO_3(s) \rightleftharpoons CaO(s) + CO_2(g)$$ Answer the fol

Volume Change Error in $$H_2S$$ Equilibrium Reaction

An experiment examines the decomposition equilibrium of hydrogen sulfide given by $$2H_{2}S ⇌ 2H_{2}

Acid/Base Structure and Selective Deprotonation

Compare acetic acid (HC₂H₃O₂) and ethanol (C₂H₅OH) in terms of their ability to donate protons in aq

Calculating pH of Salt Solutions

A solution is prepared by dissolving sodium acetate (NaC2H3O2) in water. Answer the following:

Calculating pOH and Linking to pH

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

Common Ion Effect and Solubility of Magnesium Hydroxide

Magnesium hydroxide, $$Mg(OH)_2$$, exhibits limited solubility that decreases when added to a soluti

Common Ion Effect on Hydroxide Salt Solubility

Magnesium hydroxide, Mg(OH)₂, dissolves according to the equilibrium: $$Mg(OH)_2(s) \rightleftharpo

Designing a Buffer System

Design an experiment to prepare a buffer solution that targets a pH of 7.40 for a biochemical assay.

Effect of Dilution on Buffer pH

Buffer solutions are known for maintaining a relatively constant pH even upon dilution.

Indicator Behavior in Titration

Discuss the role of pH indicators in titration experiments. Describe the necessary properties of an

Indicator Color Change and pH Transition Range

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

Indicator Selection and Color Change Analysis

Acid-base indicators are weak acids that change color when the pH approaches their pKa. Address the

Interpreting pH Variability in Environmental Waters

A researcher collects pH data from several lakes, finding values ranging from 6.2 to 8.4. Discuss th

Investigating pH Changes Upon Ion Addition

A research lab aims to study the effects of adding various ions on the pH of pure water. The experim

Investigating the Effect of Ionic Strength on Weak Acid Dissociation

This FRQ examines how changes in ionic strength affect the dissociation of a weak acid by analyzing

Neutralization Reaction in a Weak Acid-Strong Base System

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

Plotting pH Change and Indicator Transition

An indicator is added to a solution while its pH is gradually increased, and a graph of color intens

Titration Curve Analysis of a Weak Acid

A 25.0 mL sample of a weak acid is titrated with a 0.1 M strong base. The titration curve is provide

Titration Lab Analysis of a Polyprotic Acid

A laboratory experiment involves titrating a polyprotic acid with a strong base. The resulting titra

Titration of a Weak Acid with a Strong Base: Curve Analysis

In a titration experiment, 25.0 mL of 0.10 M acetic acid is titrated with 0.10 M NaOH. A titration c

Weak Acid pH Calculation and Percent Dissociation

A researcher is investigating the pH of a weak acid solution. The solution is 0.1 M acetic acid (HC2

Analyzing Gibbs Free Energy with Reaction Quotient

Consider the redox half-reaction: $$Fe^{3+} + e^- -> Fe^{2+}$$ with a standard reduction potential o

Calculating Standard Cell Potential from Half-Reactions

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

Calorimetry-Derived Thermodynamics: Misdirected Application

In an effort to determine both the enthalpy ($$\Delta H^\circ$$) and entropy ($$\Delta S^\circ$$) ch

Comparative Analysis of Reaction Spontaneity from Provided Data

The following table presents thermodynamic data for three different reactions at 298 K.

Controlled Experiment on Reaction Favorability

A laboratory is investigating the effect of reactant concentration on the potential of a galvanic ce

Coupled Reactions in Industrial Processes

In an industrial process, an endothermic reaction that is non-spontaneous is coupled with an exother

Entropy Change Analysis in Reactions

Examine the table below showing different reactions with changes in the number of gas moles along wi

FRQ 4: Calculating \(\Delta G^\circ\) from Reduction Potentials

For the galvanic cell reaction: $$Zn(s) + Cu^{2+}(aq) \rightarrow Zn^{2+}(aq) + Cu(s)$$ the standa

Galvanic Cell Design with Varying Ion Concentrations

A student constructs a galvanic cell using a silver electrode in AgNO₃ (half-reaction: $$Ag^+ + e^-

Galvanic Cell: Construction and Analysis

A galvanic (voltaic) cell is constructed to harness a spontaneous redox reaction. Consider both its

Kinetics vs. Thermodynamics of Reactions

Some reactions are thermodynamically favored (negative $$\Delta G^\circ$$) yet occur very slowly. An

Modeling Reaction Favorability Using Thermodynamic Data

Using a provided table of ΔH° and ΔS° values, determine the reaction favorability for several reacti

Phase Equilibria and Gibbs Energy

Water undergoes phase changes that can be analyzed using Gibbs free energy. Consider the liquid-gas

Reduction Potential Driven Driving Force

A paper suggests that the spontaneity of redox reactions can be completely predicted by measured red

Relating Cell Potential and Free Energy

A galvanic cell for a redox reaction has a standard cell potential $$E^\circ = 0.85\,V$$ and transfe

Standard Free Energy and Equilibrium in Redox Reactions

A media report asserts that a redox reaction with an equilibrium constant greater than 1 will necess

Temperature Dependence in Galvanic Cell Voltage

A media report suggests that the voltage output of a galvanic cell decreases linearly with increasin

Temperature Dependence of Gibbs Free Energy

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

Temperature Effects on Electroplating

An experimental study examines how temperature affects the rate of electroplating. The following dat

Thermodynamic Prediction Using Gibbs Free Energy Equation

Consider a reaction with a standard enthalpy change $$\Delta H° = -120\,kJ/mol$$ and a standard entr