AP Chemistry FRQ Room

Analysis of Periodic Table Data Graph

The following graph displays a trend in atomic radii across several elements in a period. Use the gr

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

Catalytic Reaction Rate Experiment with Temperature Control Error

A chemical kinetics experiment is carried out to study the effect of various catalysts on the rate o

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

Complex Ion Equilibria and Solubility

A solution containing 0.010 M Ag⁺ ions is mixed with 0.050 M of a ligand L to form a complex ion [Ag

Computational Study on Effective Nuclear Charge and Atomic Radius

A computational simulation was performed to study the relationship between effective nuclear charge

Coulomb's Law and Ionization Energy

Coulomb's law describes the electrostatic force between charged particles using the equation \(F =

Determining Empirical and Molecular Formulas

A compound has been analyzed and its percent composition is determined to be 56.5% carbon, 7.11% hyd

Electron Configuration and Periodic Trends

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

Electron Configuration of Transition Metals

Transition metals often show unique electron configurations due to subshell mixing. Answer the follo

Electronegativity and Bond Polarity

Bond polarity arises from differences in electronegativity. Answer the following:

Empirical and Molecular Formula Determination with Inaccurate Mass Measurement

In an experiment to determine the empirical and molecular formula of an unknown compound, a student

Empirical vs. Molecular Formulas of Organic Compounds

An organic compound is analyzed and determined to have the following percent composition: 80.0% C, 6

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 Reaction Energetics

A gaseous reaction in the laboratory is conducted at 350 K, 0.8 atm, and a volume of 22.4 L. Answer

Ideal Gas Law and Mole Determination

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

Investigating Ionization Energy Trends Across the Periodic Table

Ionization energy generally increases as you move from left to right across a period. Design an expe

Investigation of Reaction Mechanism and Rate Laws

A reaction following the overall stoichiometry $$A + B \rightarrow C$$ is observed to proceed via a

Ionization Energy Trends and Electron Shell Structure

Discuss the trends in ionization energy based on electron configuration and atomic structure.

Le Chatelier’s Principle in Industrial Equilibrium

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

Mass Spectrometry and Isotope Abundance Determination

Using mass spectrometry data, evaluate the isotope distribution of selenium.

Mass Spectrometry of Selenium Isotopes

A laboratory uses mass spectrometry to analyze selenium and determine its isotopic abundances. The m

Mole Calculations in Chemical Reactions

In a laboratory experiment, a chemist measures a 24.022 g sample of carbon and uses it in a combusti

Moles and Mass Conversions in Biochemistry

Glucose (\(C_6H_{12}O_6\)) plays an important role in metabolism. Answer the following: (a) Calcula

Moles and Molar Mass Conversion

A sample of carbon weighing $$24.022$$ grams is used in an experiment. Given the atomic mass of carb

Photoelectron Spectroscopy Analysis

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

Reaction Enthalpy and Thermochemistry

Consider the reaction: $$CH_4 + 2\,O_2 \rightarrow CO_2 + 2\,H_2O$$. Using the standard enthalpies o

Advanced Ionic Compound Lattice Energy Analysis: A Comparative Study

In this question, you will derive the relationship between ionic charges, interionic distance, and l

Alloy Formation: Substitutional vs. Interstitial

Discuss the formation of substitutional and interstitial alloys with a focus on atomic sizes and bon

Bonding Type and Solubility

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

Comparing Single, Double, and Triple Bonds

This question examines the differences among single, double, and triple bonds in terms of bond lengt

Covalent Bonding and Internuclear Distance Analysis

Analyze how the internuclear distance affects the potential energy in covalent bonds using a potenti

Determination of Bonding Type through Conductivity Experiments

An experiment measures the electrical conductivity of substances in their molten state. The substanc

Formal Charge and Lewis Structure Validation in Nitrate Ion

For the nitrate ion (NO3^-), developing an accurate Lewis structure is essential. Answer the followi

Formal Charge and Resonance Stability in Nitrate Ion

This question requires you to define formal charge, calculate it, and use it to compare the stabilit

FRQ 18: Predicting Molecular Geometry from Hybridization

A table provides information on the hybridization and observed molecular geometries of several molec

FRQ6: Designing a Synthesis of PF₅ – Expanded Octet and Lewis Structures

Phosphorus pentafluoride (PF₅) is an example of a molecule where the central atom expands its octet.

Investigating Lone Pair Repulsions and Molecular Shape

This question requires you to analyze the structure of $$\text{XeF}_4$$ by drawing its Lewis structu

Lewis Structure and Resonance in the Sulfate Ion

A chemist is studying the sulfate ion ($$\text{SO}_4^{2-}$$) to understand its bonding and stability

Metallic Bonding and Electrical Conductivity

A researcher examines the electrical conductivity of pure metals and their alloys over a range of te

Metallic Conduction and Temperature Dependence

A student investigates the effect of temperature on electrical conductivity in a metallic sample. Th

Molecular Geometry and Lone Pair Influence

A student investigates the molecular geometry of ammonia ($$NH_3$$) using microwave spectroscopy to

Molecular Geometry of Sulfur Tetrafluoride (SF4)

A researcher synthesizes sulfur tetrafluoride ($$\text{SF}_4$$) and seeks to understand its bonding

Network Covalent Bonding and Physical Properties

Network covalent solids exhibit unique physical properties owing to their extensive bonding networks

Network Covalent Structures: Comparing Diamond and Graphite

A materials scientist compares diamond and graphite, two allotropes of carbon with very different ph

Potential Energy Curve Analysis of Covalent Bond Formation

A potential energy diagram for a covalent bond shows different regions labeled A, C, and D. Analyze

Quantitative Analysis of Bond Energy from Graph Data

Using a potential energy graph for a diatomic molecule, analyze the bond energy quantitatively.

Resonance and Bond Order Calculation

This question focuses on the effect of resonance on bond characteristics, particularly bond order, a

Resonance in the Carbonate Ion

A chemist is examining the structure of the carbonate ion ($$\text{CO}_3^{2-}$$) to understand reson

Resonance Structure Misinterpretation in Lewis Dot Structures

A student is assigned to draw the Lewis dot structures for the carbonate ion ($$CO_3^{2-}$$) and the

Temperature Dependence of Metallic Conductivity

An experiment was performed to investigate how the electrical conductivity of a metal changes with t

Chromatography Separation Techniques

A chemist is evaluating different chromatography methods to separate a mixture of compounds. Answer

Chromatography: Separation of Mixed Pigments

In this question, you will use paper chromatography data to analyze pigment separation based on pola

Comparing Dipole-Dipole and Hydrogen Bonding Effects on Boiling Points

Molecular interactions such as dipole-dipole forces and hydrogen bonds significantly influence boili

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 Density and Molar Mass

A gas in a container at 1 atm and 300 K has a density of $$0.8\;g/L$$. Using the equation $$MM = \fr

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

Effusion Experiment Analysis

Analyze the effusion behavior of gases to understand how molar mass influences the rate of effusion

Electromagnetic Spectrum and Electron Transitions

The quantized energy levels of electrons in an atom mean that electrons absorb or emit energy in dis

Energy Transitions and the Electromagnetic Spectrum

Evaluate the relationship between wavelength and the type of energy transition in atoms using the pr

Hydrogen Bonding and Boiling Point Analysis

Water and ammonia are two polar molecules with significantly different boiling points (100°C for wat

Ideal Gas Law and Density Derivations

The ideal gas law can be manipulated to derive useful expressions for properties like density. Work

Impact of Molecular Geometry on Polarity

Even when individual bonds in a molecule are polar, the overall molecular polarity depends on molecu

Kinetic Molecular Theory and Ideal Gas Behavior

This question involves the kinetic molecular theory and how it explains the behavior of an ideal gas

Kinetic Molecular Theory and Molecular Speeds

A researcher investigates how molecular mass influences the speed distribution of gas molecules in t

Lattice Energy and Melting Points

The lattice energy of an ionic compound provides insight into the strength of the forces holding the

Maxwell–Boltzmann Diagram Interpretation and Temperature Effects

A Maxwell–Boltzmann diagram shows the distribution of molecular speeds at two different temperatures

Quantitative Analysis Using Beer’s Law for Concentration Determination

Utilize the provided absorbance data to explore the relationship between concentration and absorbanc

Solvent Polarity and Dipole Interactions

The solubility of substances depends heavily on the intermolecular forces present. A polar solute ge

Spectroscopy: Electronic Transitions

A molecule’s absorption spectrum is used to study its electronic transitions. Answer the following:

Vibrational Energy Transitions

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

Acid-Base Reaction and Titration Analysis

A strong acid reacts with a strong base in a titration experiment. Consider the reaction between hyd

Acid-Base Titration Curve Analysis

A titration experiment is conducted by titrating 0.10 M HCl with 0.10 M NaOH. The following table re

Analyzing a Decomposition Reaction Experiment

A researcher studies the decomposition of compound MX2, which breaks down upon heating into metal M

Analyzing Redox Titration using KMnO4

In a redox titration, an iron(II) solution is titrated with 0.0200 M potassium permanganate (KMnO4)

Application of the Ideal Gas Law in Reaction Conditions

A reaction that produces a gaseous product is carried out in a sealed 10.0 L container at a temperat

Balancing Redox Reactions in Basic Solutions

In a basic solution, iodide ions (I−) are oxidized to iodine (I2). Answer the following: (a) Write

Chemical Equilibrium in Acid-Base Reactions

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

Combustion Analysis of a Hydrocarbon

Combustion analysis can be used to determine the empirical formula of an unknown hydrocarbon. Design

Combustion Analysis of Hydrocarbons

Butane (C4H10) combusts in oxygen to produce carbon dioxide and water. In one experiment, 44.0 g of

Decomposition Reaction and Stability Analysis

Compound AB decomposes when heated according to the reaction: $$AB \rightarrow A + B$$. Experimental

Designing a Half-Reaction Balancing Experiment

Redox reactions require careful balancing using half-reactions. Design an experiment that demonstrat

Determination of Oxidation States

Assign oxidation states to the elements in the following compounds:

Determining Empirical Formula from Combustion Data

An unknown hydrocarbon is combusted completely, producing 33.0 g of CO2 and 14.0 g of H2O. Answer th

Electrochemical Cell Analysis

A voltaic cell is constructed with a zinc electrode immersed in 1.0 M $$ZnSO_4$$ solution and a copp

Environmental Impact of Acid Rain

A limestone monument primarily composed of $$CaCO_3$$ is exposed to acid rain with a pH of 3. The re

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 9: Temperature Effects on Decomposition Reactions

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

FRQ 12: Interpreting a Graph of Reaction Kinetics

A graph is provided showing the natural logarithm of the reactant concentration (ln[A]) versus time

FRQ 13: Balancing Complex Redox Reactions

Balance the redox reaction involving the oxidation of $$Fe^{2+}$$ to $$Fe^{3+}$$ by $$MnO_4^-$$ in a

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

Gravimetric Analysis for Determining Unknown Alkali Hydroxide

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

Gravimetric Analysis of Alkali Hydroxides

A 4.33 g sample of an unknown alkali hydroxide (MOH) is completely dissolved in water. An excess of

Gravimetric Analysis of an Unknown Alkali Hydroxide

A 4.33 g sample of an unknown alkali hydroxide is dissolved in water. Excess copper(II) nitrate is a

Gravimetric Method for Determining Ion Concentration

A gravimetric analysis is performed to determine sulfate ion concentration by precipitating it as ba

Integrated Analysis of Water Treatment Process

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

Interpreting Oxidation States in Redox Reactions

Examine the following redox reaction: $$Fe + 2*HCl → FeCl_{2} + H_{2}$$.

Investigating Oxidation State Changes via Spectrophotometry

Spectrophotometry can be an effective tool to monitor oxidation state changes during a redox reactio

Kinetics of Decomposition Reactions

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

Precipitation Reaction and Solubility Analysis

A 0.10 M solution of AgNO₃ is mixed with an equal volume of a 0.10 M solution of NaCl. Answer the fo

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

Precipitation Reaction for Chloride Ion Identification

A student conducts a qualitative analysis to detect chloride ions by adding silver nitrate solution

Quantitative Analysis With Percent Error

Percent error is used to compare experimental yields with theoretical predictions. Design an experim

Reaction Kinetics in Decomposition of Hydrogen Peroxide

A laboratory experiment investigates the decomposition of hydrogen peroxide (\(H_2O_2\)) catalyzed b

Redox Titration Analysis

A redox titration is performed using 0.1000 M potassium permanganate ($$KMnO_4$$) to determine the c

Redox Titration Experiment: KMnO4 with Oxalate Ion

In an acidic medium, potassium permanganate (KMnO4) is titrated against a solution containing the ox

Solubility Equilibria in Precipitation Reactions

Silver chloride (AgCl) precipitates from solution according to the reaction: $$Ag^+(aq) + Cl^-(aq) \

Thermochemistry of Benzene Combustion

Benzene ($$C_6H_6$$) combusts with oxygen to produce carbon dioxide and water. Using the standard en

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

Writing and Balancing Redox Reactions

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

Analysis of Collision Theory and Reaction Energy Profile

Collision theory provides an explanation for the observed rate of reaction, and an energy profile di

Analysis of Reaction Kinetics Using Initial Concentration Data

A reaction, $$A + 2*B + C \to D$$, was investigated using a series of experiments. The following tab

Catalysts and Reaction Mechanisms

Consider the overall reaction $$A + B \to C$$ which proceeds via the following two-step mechanism:

Competitive Parallel Reaction Mechanisms

In a system where reactant A can undergo two parallel reactions to form products B and C, the follow

Constructing an Arrhenius Plot and Calculating Activation Energy

A reaction’s rate constant k has been measured at various temperatures as provided in the table belo

Correlation between Reaction Mechanism Steps and Experimental Rate Law

A reaction is proposed to proceed by two different mechanisms. One mechanism is a single-step, bimol

Derivation of Integrated Rate Laws

Derive the integrated rate laws for first-order and second-order reactions starting from their respe

Deriving Integrated Rate Law from Differential Equations for a First Order Reaction

Given the differential rate equation for a first order reaction, $$\frac{d[A]}{dt} = -k*[A],$$ answe

Deriving Net Rate Law from Multi-Step Reaction Mechanism

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

Determining a Reaction Mechanism from Experimental Data

Experimental data for the reaction $$P + Q \rightarrow R$$ are provided in the stimulus. Analyze the

Determining Rate Law from Reaction Mechanisms

A reaction proceeds through multiple steps. The proposed mechanism is as follows: I. A + A ⇌ X (fas

Determining Reaction Kinetics from Time-Concentration Data

Experimental data for the concentration of reactant A over time are provided below. Use the data to

Determining Reaction Mechanisms from Isotope Labeling Experiments

A researcher uses isotopically labeled reactants to study the mechanism of a complex reaction. The f

Determining Reaction Order from Initial Rate Data

A reaction with the overall equation $$A + 2*B + C \rightarrow D$$ was studied through several exper

Determining Reaction Rate Law for the Reaction $$2NO + O_2 \rightarrow 2NO_2$$

A series of experiments were conducted for the reaction $$2NO + O_2 \rightarrow 2NO_2$$. Use the tab

Determining Reaction Rate Laws from Experimental Data

A series of experiments were conducted to study the reaction $$A + 2*B + C \rightarrow D$$. Use the

Effect of Catalysts on Reaction Rate

Catalysts are known to alter the pathway of a reaction. Answer the following parts regarding their i

Effect of Solvent Polarity on Reaction Kinetics

A reaction is performed in two different solvents: one polar and one non-polar. The measured rate co

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

Half-Life Analysis Across Reaction Orders

Half-life is a useful concept in kinetics. (a) Define the half-life of a reaction and derive the ha

Identifying and Explaining Intermediates in Reaction Mechanisms

Intermediates play a key role in multi-step reaction mechanisms. Answer the following parts.

Influence of Surface Area on Reaction Kinetics in Heterogeneous Mixtures

Heterogeneous reactions often occur at the interface between phases. Answer the following parts rega

Kinetic Data Analysis from Concentration vs Time Table

A series of experiments provided concentration data for reactant A over time. Analyze the data to de

Overall Rate Law for Complex Reactions with Intermediates

A complex reaction proceeds through multiple steps involving intermediates. A proposed mechanism is

Reaction Energy Profile and Catalysis

Examine the reaction energy profile provided and answer the following parts related to activation en

Using Concentration-Time Data to Determine Half-Life in a First-Order Reaction

A first-order reaction was monitored by measuring the concentration of reactant A at regular time in

Zero-Order Reaction Kinetics

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

Analysis of Reaction Mechanisms Through Bond Energy Considerations

Consider the combustion reaction: $$\text{C}_2\text{H}_6 + \text{O}_2 \rightarrow \text{CO}_2 + \tex

Calculation of Reaction Enthalpy Using Bond Energies and Hess's Law

Consider the reaction: $$N_2(g) + 3 H_2(g) \rightarrow 2 NH_3(g)$$. Given the following bond energie

Calorimetric Determination of Specific Heat

A student conducted a calorimetry experiment by heating a metal to 100°C and then quickly placing it

Calorimetry of Enthalpy of Combustion with Radiation Loss

A student performs a combustion experiment using a simple calorimeter to measure the enthalpy of com

Comparison of Heat Flow in Different Materials

A graph compares the temperature change over time for two different substances when the same amount

Designing an Experiment: Measuring Specific Heat Capacity

A research group claims to have developed a novel method to measure the specific heat capacity of a

Determining Overall Reaction Enthalpy Using Hess's Law

A reaction is carried out in two steps: Step 1: $$A → B$$, ΔH = +50 kJ Step 2: $$B → C$$, ΔH = -80 k

Determining Reaction Enthalpy from Bond Energies

A claim is made that the enthalpy change of a reaction can be accurately determined by using average

Energy Diagrams: Exothermic vs Endothermic Reactions

This FRQ requires you to draw and interpret energy diagrams for exothermic and endothermic reactions

Energy Transfer in Redox Reactions of Rechargeable Batteries

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

Enthalpy Change Calculation from Bond Energies

Consider the combustion reaction of ethane given by $$C_{2}H_{6} + \frac{7}{2}O_{2} \rightarrow 2CO_

Enthalpy Change in Neutralization Reactions

In an aqueous neutralization reaction, a calorimeter records that 100 g of water experiences a tempe

Experimental Design: Measuring Activation Energy

A media report claims that temperature measurements from a reaction vessel can directly determine th

Hess’s Law Application Problem Using Enthalpies of Formation

A chemist examines the formation of methanol from its constituent elements using the reaction: $$C(s

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

Measurement of Enthalpy of Vaporization

In an effort to measure the enthalpy of vaporization of a liquid, a student sets up an experiment us

Multi-Step Enthalpy Calculation Using Hess's Law

A complex reaction can be broken into three steps as shown below: Step 1: $$A + B \rightarrow C$$, $

Neutralization Reaction and Calorimetry

Investigate the neutralization reaction between an acid and a base using calorimetry to determine th

Phase Changes and Energy Diagrams: Melting and Vaporization

A sample of a pure substance is heated from solid to gas in an experiment conducted at 1 atm pressur

Pressure Effects on Reaction Enthalpy in a Sealed Vessel

A student studies how varying the pressure in a sealed reaction vessel affects the observed reaction

Reaction Energy Diagram Analysis

An energy diagram for a multistep reaction is provided, showing two distinct transition states and a

Testing Hess's Law Through a Multi-Step Reaction Pathway Design

Hess's Law allows the determination of a reaction's overall enthalpy change by summing the enthalpy

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

Analyzing Temperature Dependence of $$K_{eq}$$

A reaction has measured equilibrium constants at different temperatures. Using the van't Hoff equati

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

Calculating Partial Pressures in Gaseous Equilibrium (Kp Calculation)

For the gaseous reaction $$A(g) + 2*B(g) \rightleftharpoons 3*C(g)$$, the equilibrium constant can b

Calculations Involving Common Ion Effect on Solubility

Consider the dissolution of lead(II) chloride: $$\rm PbCl_{2}(s) \rightleftharpoons Pb^{2+}(aq) + 2C

Common Ion Effect on Solubility Product

An experiment studies the solubility of silver chloride (AgCl) in pure water and in a solution conta

Common Ion Effect: AgCl Solubility

Consider the dissolution of silver chloride: $$\mathrm{AgCl(s) \rightleftharpoons Ag^{+}(aq) + Cl^{-

Common Ion Effect: Predicting Precipitation in Mixed Solutions

Silver chloride, $$AgCl(s)$$, is sparingly soluble and dissociates as: $$AgCl(s) \rightleftharpoons

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

Comparing Kc and Kp in Gas Equilibria

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

Concentration Changes in Aqueous Equilibria

The reaction $$Fe³⁺(aq) + SCN⁻(aq) \rightleftharpoons FeSCN²⁺(aq)$$ is monitored via its color inten

Constructing Equilibrium Expressions and Unit Analysis

For the heterogeneous reaction $$\text{CaCO}_3 (s) \leftrightharpoons \text{CaO} (s) + \text{CO}_2 (

Decomposition of PCl5: Misinterpretation of Pressure Effects

In an experiment investigating the equilibrium of the reaction $$PCl_5 (g) \rightleftharpoons PCl_3

Deriving Kp from Kc for a Gaseous Reaction

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

Deriving New Equilibrium Expressions from Multiple Reactions

Given two reactions: Reaction 1: $$P \rightleftharpoons Q$$ with equilibrium constant $$K_1$$ Reac

Determining Acid Dissociation Constant (Ka)

For the weak acid HA, which dissociates in water according to $$HA + H_2O \leftrightarrow A^- + H_3O

Determining Molar Solubility from Ksp

A slightly soluble salt, $$MX_{2}$$, dissociates according to the equation: $$MX_{2}(s) ⇌ M^{2+}(aq)

Dilution Effects on Aqueous Equilibria

Investigate the impact of dilution on an aqueous equilibrium system.

Dilution Impact on Aqueous Equilibrium

A research team is studying the equilibrium for the reaction $$Fe^{3+} + SCN^{-} ⇌ FeSCN^{2+}$$ in a

Effect of Catalysts on Equilibrium Dynamics

Investigations were conducted on the reaction D ⇌ E + F to compare the time required to reach equili

Environmental Chemistry and Solubility Equilibria

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

Equilibrium in a Pre-Equilibrium Mechanism

Consider a reaction mechanism for the formation of product $$D$$ occurring in two steps: Step 1 (fa

Equilibrium in Environmental Systems: Carbonic Acid Formation

The formation of carbonic acid in water is represented by the equilibrium: $$CO_2(g) + H_2O(l) \righ

Experimental Uncertainty and Equilibrium Constant Determination

When determining an equilibrium constant (Keq) experimentally, various sources of error can affect t

Gas-Liquid Equilibrium: Henry’s Law and Reaction Equilibrium

Consider the reaction: $$O_2(aq) + 2X(aq) \rightleftharpoons Y(aq)$$, where the solubility of O₂ in

Graphical Analysis of Reaction Progress

A researcher records the value of the reaction quotient $$Q$$ over time for a gas-phase reaction and

Graphical Interpretation of Concentration-Time Data in a Gas Reaction

The reaction $$\mathrm{A (g) + B (g) \rightleftharpoons C (g)}$$ was monitored, and the following gr

Graphing Equilibrium Dynamics

Interpret a graph showing the concentration changes of reactants and products over time in a reactio

Haber Process Equilibrium Error Analysis

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

Impact of Dilution on an Aqueous Equilibrium

An equilibrium system involving aqueous ions is represented by the reaction: $$Fe^{3+}(aq) + SCN^{-}

Influence of Reaction Coefficients on Rate and Equilibrium

Consider a reaction where stoichiometric coefficients influence the rate at which reactants are cons

Ionic Strength Effect Misinterpretation in Multi-Component Equilibrium

An experiment is conducted to study the formation of the complex ion $$[Cu(NH_3)_4]^{2+}$$ in soluti

Kinetics vs Equilibrium in a Multi-step Reaction

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

Manipulating Combined Equilibria

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

Manipulating Equilibrium Constants Using Hess's Law

Given the following reactions: 1) $$A (g) \rightleftharpoons B (g)$$ with $$K_1 = 4.0$$ 2) $$2*B (g)

Manipulation of Equilibrium Expressions: Coefficient Changes and Reversals

For the reaction $$X (g) + 2*Y (g) \rightleftharpoons 3*Z (g)$$, analyze how modifications affect th

Multiple Equilibria in Aqueous Systems

In an aqueous solution, two equilibria occur simultaneously: (1) $$C(aq) + D(aq) \rightleftharpoons

Pressure Effects in Gas-Phase Equilibria

Examine the following gas-phase reaction: $$NO_2 \leftrightharpoons NO + O_2$$. Answer the following

Pressure Effects on Equilibrium Dynamics

Examine a gaseous equilibrium reaction and its response to pressure changes.

Quantitative Reaction Quotient

For the gaseous reaction: $$CO (g) + Cl_2 (g) \rightleftharpoons COCl_2 (g)$$, consider the initial

Reaction Quotient (Q) versus Equilibrium Constant (K)

For the reaction W ⇌ X, initial experimental measurements yield [W] = 0.20 M and [X] = 0.10 M, with

Reaction Quotient and Equilibrium Shift

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

Relating $$K_p$$ and $$K_c$$ for Gaseous Reactions

For the gas-phase reaction: $$L(g) + 2\,M(g) \rightleftharpoons N(g)$$, the relationship between $$K

Solubility and pH Influence on Metal Hydroxide Equilibrium

A metal hydroxide, $$M(OH)_2$$, dissolves according to the equilibrium: $$M(OH)_2(s) \rightleftharp

Temperature Effect in an Exothermic Reaction Experiment

In an experiment designed to study the effect of temperature on an exothermic reaction given by $$A

Temperature Effects on Equilibrium in an Exothermic Reaction

A laboratory is studying an exothermic reaction: $$X + Y \rightleftharpoons Z + energy$$. At $$T_1 =

Visual Analysis of Equilibrium Diagram

A schematic diagram of a generic equilibrium reaction is provided. The diagram shows reactants and p

Analysis of Polyprotic Acids

Phosphoric acid (H₃PO₄) is a polyprotic acid with dissociation constants $$K_{a1} = 7.1 \times 10^{-

Buffer Response to Acid Addition

A buffer solution is prepared by mixing 0.25 M acetic acid (HC₂H₃O₂) with 0.25 M sodium acetate (NaC

Buffer System pH Calculation

A buffer solution is prepared by mixing equal volumes of 0.20 M acetic acid (HC2H3O2) and 0.10 M sod

Calculating pH in a Buffer using the Henderson-Hasselbalch Equation

A student prepares a buffer solution containing 0.1 M acetic acid and 0.1 M sodium acetate. Analyze

Calibration of a pH Meter in Acidic Solution Titration

In a titration experiment, a student notices inconsistent pH meter readings. Describe the proper pro

Common Ion Effect on Hydroxide Salt Solubility

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

Common Ion Effect on Solubility of Mg(OH)₂

This question examines the impact of the common ion effect on the solubility of magnesium hydroxide.

Comparative Analysis of Strong vs. Weak Acid pH

Acids differ in their ability to donate protons due to their degree of ionization, affecting the pH

Comparative Titration Curve Analysis

A chemist performs two titrations: one of a strong acid (HCl) with a strong base (NaOH), and one of

Designing a Titration Experiment for a Polyprotic Acid

A chemist wishes to titrate phosphoric acid (H3PO4) with a strong base. Answer the following:

Designing a Titration Experiment to Determine Weak Acid Concentration

This FRQ involves designing a titration experiment to determine the concentration of a weak acid usi

Determining pKb from a Known pKa

A study of conjugate acid-base pairs involves using the relation $$pK_a + pK_b = 14$$. For acetic ac

Effect of Concentration on pH of Weak Acids

A researcher observes that diluting a weak acid solution increases its percent dissociation, thereby

Environmental Chemistry: Impact of Acid Rain on Freshwater pH

Acid rain has been affecting a freshwater lake, causing a decrease in its pH and negatively impactin

Neutralization Reaction Error in Weak Base Titration

A student performed a titration of ammonia (NH₃), a weak base, with a strong acid (HCl). The student

pH Calculation of Strong Acid

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

pH Calculation of Strong Base

A 0.010 M NaOH solution is prepared. First, calculate the pOH using the formula $$pOH = -\log([OH^-]

Relationship Between $$K_a$$, $$K_b$$, and $$K_w$$

For a conjugate acid-base pair, the relationship $$K_a \times K_b = K_w$$ holds true. Given a weak a

Stepwise Dissociation of a Polyprotic Acid

A 0.1 M solution of phosphoric acid (H₃PO₄) is prepared. Considering its stepwise dissociations with

Titration Curve of a Weak Base

During the titration of a weak base (NH₃) with a strong acid (HCl), the titration curve exhibits dis

Weak Acid Dissociation and Percent Ionization

The percent dissociation of a weak acid gives insight into its strength and ionization behavior in s

Weak Acid Percent Dissociation Analysis

Consider a 0.050 M acetic acid solution with a dissociation constant $$K_a = 1.8 \times 10^{-5}$$. T

Catalysts and Free Energy

A catalyst is added to a reaction that has a standard free energy change of \(\Delta G^\circ = +25\,

Charge Transfer and Reaction Kinetics Misinterpretation in Electrolysis

A researcher designed an electrolysis experiment to produce hydrogen and oxygen by electrolyzing wat

Comparative Analysis of Reaction Spontaneity from Provided Data

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

Comparing Galvanic and Electrolytic Cells

A table below compares key properties of galvanic (voltaic) cells and electrolytic cells. Analyze th

Comparison between Galvanic and Electrolytic Cells

Compare and contrast galvanic and electrolytic cells with regard to their spontaneity, cell potentia

Correlation Between Entropy and Temperature in a Reaction

A study claims that increasing the temperature of a reaction always leads to a higher system entropy

Corrosion Protection via Sacrificial Anodes

A coastal facility experiences rapid corrosion of aluminum structures. An engineer proposes using a

Determining $$\Delta G^\circ$$ from Equilibrium Constant Data

A chemist aimed to calculate the standard free energy change ($$\Delta G^\circ$$) for the reaction $

Electroplating Current Calculation

An electrolytic cell is used for electroplating a metal. The cell is operated at a constant current

Entropy Change and Reaction Spontaneity

A chemist is studying the reaction $$2*A(g) + B(l) -> 3*C(g)$$. Standard entropy values for each spe

Entropy Change Calculation and Interpretation

Consider the reaction: $$A_{(l)} + 2B_{(s)} \rightarrow 3C_{(g)}$$. A table of standard entropy valu

Entropy Changes in Chemical Reactions

Consider the reaction $$2NO_2(g) \rightarrow 2NO(g) + O_2(g)$$. Discuss the change in entropy $$\Del

Evaluating Reaction Conditions for Electrolysis

An electrolytic cell is used to decompose water with a constant current of $$1.5\,A$$ applied for $$

Evaluating the Role of Temperature in Enthalpy and Entropy Contributions

An experiment examines how temperature variations affect the balance between enthalpy (∆H°) and entr

Explaining the Role of the Salt Bridge in Galvanic Cells

Examine the provided schematic diagram focusing on the salt bridge in a galvanic cell.

FRQ 16: Nernst Equation Under Concentration Variations in Electrolytic Cells

In an electrolytic cell, the reduction half-reaction for permanganate is given by: $$MnO_4^- + 8H^+

Influence of Ionic Strength on Electrolytic Processes

A study is conducted on the effect of ionic strength on the performance of electrolytic cells. Resea

Investigating Non-Standard Conditions in Galvanic Cells

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

Investigation of Electrochemical Corrosion

Design an experiment to investigate the electrochemical corrosion of a metal under varying environme

Redox Reaction Efficiency Analysis

A study examines the efficiency of a redox process by comparing the theoretical and actual yields of

Relating Gibbs Free Energy and Electric Current in Electrochemical Cells

A researcher investigates the relationship between the Gibbs free energy change (∆G°) of a cell reac

Thermodynamic vs Kinetic Control in Reactions

Some reactions exhibit a negative \(\Delta G°\) (thermodynamically favored) but proceed very slowly