AP Chemistry FRQ Room

Acid-Base Titration Conceptual Error in Endpoint Determination

In an acid-base titration experiment to determine the concentration of acetic acid, a student uses a

Advanced Coulomb's Law Application in Ionic Bonding

Consider two ionic compounds. Compound A consists of ions with charges $$+1$$ and $$-1$$ separated b

Analyzing Electron Shielding Effect in Successive Elements

This question examines how electron shielding affects the effective nuclear charge, and how this in

Application of Coulomb's Law and the Bohr Model

Apply Coulomb's law and the Bohr model to analyze atomic interactions.

Atomic Structure and Isotopic Abundance Analysis

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

Aufbau Principle and Electron Configuration Anomalies

Some transition metals exhibit electron configurations that deviate from the expected order. Answer

Effect of Electron Configuration on Chemical Bonding Patterns

This question examines how electron configuration influences the formation and characteristics of di

Electron Configuration Anomalies: Case of Copper

Copper has an unusual electron configuration due to stability considerations. Answer the following:

Electronegativity and Bond Polarity

Consider a carbon-oxygen bond. Given the electronegativity of carbon is 2.55 and that of oxygen is 3

Empirical and Molecular Formula Determination

A compound is analyzed and found to have the following percent composition: 40% carbon, 6.7% hydroge

Evaluating Chemical Reactivity Based on Electron Configuration

Electron configuration greatly influences an element's chemical reactivity. Design an experiment to

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

Gravimetric Analysis for Determining Percent Composition

Gravimetric analysis is a quantitative method for determining the percent composition of a compound.

Ideal Gas Law Application under Non-STP Conditions

A gas is contained in a 2.00 L vessel at an initial pressure of 1.50 atm and temperature of 350 K. C

Ideal Gas Law: Gaseous Reaction Experiment

A chemical reaction conducted in a closed container produces a gas. The measured conditions are: pre

Interpreting Electron Configuration Diagrams

A diagram shows the electron configuration for Element X as follows: $$1s^2, 2s^2, 2p^6, 3s^2, 3p^4$

Interpreting Isotopic Mass Spectrum of Selenium

The following graph displays the mass spectrum of selenium, with peaks corresponding to its naturall

Ionization Energy Trends Analysis

Consider the ionization energies for sodium (Na) and magnesium (Mg). Data indicates that the first i

Isotopic Abundance Analysis for Carbon

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

Kinetic Energy of an Ejected Electron

In photoelectron spectroscopy, when a photon ejects an electron, the energy of the photon is consume

Mass Spectrometry and Isotopic Abundance

A mass spectrum of selenium shows five naturally occurring isotopes. Consider the following simplifi

Mass Spectrometry of Selenium Isotopes

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

Mole Calculations and Gas Laws

Work through basic mole calculations and evaluate a media claim regarding gas volumes at STP.

Mole-to-Particle Conversions and Stoichiometry

Convert between moles, number of particles, and mass, and analyze the impact of measurement uncertai

Moles and Mass Conversions in Biochemistry

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

Percent Composition of Calcium Nitrate

You will calculate the percent composition by mass for the compound calcium nitrate, Ca(NO₃)₂.

Periodic Trends and Ionization Energy Investigation

In this experiment, a researcher measured the first ionization energies of elements across a period.

Photoelectron Spectroscopy Data Interpretation

The attached graph represents a simplified photoelectron spectrum for an element, showing distinct p

Quantitative Analysis of Reaction Yield

A reaction starting with 10.0 g of compound A is expected to produce 15.0 g of compound C theoretica

Transition Metals and Variable Oxidation States

A chemist investigates copper compounds, noting that copper can exist in more than one oxidation sta

Validating the Aufbau Principle Through Spectroscopic Analysis

The Aufbau principle describes the order in which electrons fill atomic orbitals. Design an experime

Alloy Hardness Measurement and Interstitial Alloy Misinterpretation

A student investigates the effect of carbon interstitials on the hardness of iron alloys. The experi

Bond Order, Bond Length, and Experimental Correlations

This question explores the theoretical relationship between bond order, bond length, and bond energy

Catalysis in Covalent Bond Formation Kinetics

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

Comparative Analysis of Covalent and Ionic Bonding in Everyday Materials

This question asks you to compare the properties of substances with covalent and ionic bonds and to

Comprehensive Lewis Structure and Formal Charge Analysis in Sulfate Ion

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

Conductivity in Different Phases: Bonding Type Analysis

The electrical conductivity of substances in various phases depends on the type of bonding present.

Constructing Lewis Dot Structures with Incomplete Octets

Draw the Lewis dot structure for boron trifluoride (BF3) and explain its deviation from the octet ru

Determining Bonding Type Through Melting Points

A media article suggests that the melting point of a substance is a reliable metric for determining

Electronegativity and Bond Polarity

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

Evaluating PF5: Expanded Octet and Molecular Geometry

Phosphorus pentafluoride (PF5) is a classic example of a molecule that involves an expanded octet. E

Expanded Octets and Their Chemical Implications

Some atoms can have more than eight electrons around their central atom. Analyze the concept of an e

FRQ 1: Ionic Bonding – Lattice Energy Analysis

Using the table provided, analyze the relationship between lattice energy and melting point in ionic

FRQ 10: Bonding and Electrical Conductivity Across Phases

The following table summarizes the electrical conductivity of substances with different types of bon

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

FRQ7: Exploring Incomplete Octets – The Lewis Structure of BF₃

Some molecules are stable despite not having a complete octet of electrons on the central atom. Answ

FRQ17: Determining Molecular Geometry through VSEPR

A laboratory exercise involves determining the molecular geometry of various compounds using experim

FRQ19: Impact of Ionic Radii on Lattice Structures

The lattice structure of ionic compounds depends significantly on the sizes of the constituent ions.

Hybridization and Bonding in Ethene

Ethene ($$\text{C}_2\text{H}_4$$) contains a double bond made up of a sigma bond and a pi bond. A re

Hybridization and VSEPR in $$XeF_4$$

A research group examines $$XeF_4$$ to determine the hybridization of xenon and its molecular geomet

Investigating Ionic Bond Strength via Melting Point Observations

This question explores how ionic bond strength, as reflected in melting points, varies with ionic ch

Ionic Lattice Energy and Coulomb's Law

A solid ionic compound’s lattice energy can be estimated using Coulomb’s law. For an ionic compound,

Molecular Geometry and Lone Pair Influence

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

Molecular Geometry and VSEPR Analysis

A recent study challenges the predictive power of VSEPR theory by using examples of molecules with d

Molecular Geometry Determination of AX2E2 Type

Determine the molecular geometry of a molecule with four electron groups (two bonding pairs and two

Properties of Network Covalent Solids: Diamond vs Graphite

Network covalent solids like diamond and graphite exhibit drastically different physical properties

Studying Lewis Structures and Their Limitations

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

Advanced Chromatographic Analysis

Analyze column chromatography data to compute separation factors and suggest modifications to improv

Assessment of Phase Transition Analysis Based on Intermolecular Forces

A student conducts an experiment to measure the phase transition temperatures (melting and boiling p

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 using Retention Factor (Rf)

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

Column Chromatography and Separation of Mixtures

A chemist is using column chromatography to separate a mixture of compounds with varying polarities.

Combined Gas Law Application

A sample of gas initially has a pressure $$P_{1}= 2\ \text{atm}$$, a volume $$V_{1}= 10\ \text{L}$$,

Dalton's Law in Gas Mixtures

In an experiment, a container holds a mixture of gases at a total pressure of 3.0 atm. The moles of

Designing a Column Chromatography Experiment

Column chromatography utilizes polarity differences to separate mixtures. Develop an experimental de

Determination of Molar Mass from Gas Density

It is possible to determine the molar mass of a gas from its measured density. Derive the expression

Effusion and Gas Kinetics

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

Effusion Rate and Molar Mass Calculation

Use Graham's law to determine the molar mass of an unknown gas by comparing effusion rates and discu

Effusion Rates and Gas Molecules

This question examines how molecular mass influences the rate of effusion. Use Graham's Law to compa

Energy Required to Melt a Network Solid

Quartz (SiO2) is a network solid with very strong bonds. It is reported that the energy required to

Energy Transition in the Electromagnetic Spectrum

Calculate the energy change for an electron transitioning between energy levels when absorbing light

Explaining Deviations from Ideal Gas Behavior

Real gases show deviations from ideal behavior under certain conditions. Provide both qualitative an

Gas Mixtures, Reaction Rates, and Kinetic Theory

During a combustion reaction, the reaction rate is influenced by the kinetic energy of gas molecules

Hydrogen Bonding in Water vs. Ammonia

A researcher investigates the role of hydrogen bonding in determining the physical properties of wat

IMF Effects on Boiling Points

The strength of intermolecular forces (IMFs) affects boiling points. Consider three substances with

Intermolecular Forces Ranking in Different Substances

Consider four substances: iodine (I2), water (H2O), oxygen (O2), and sodium chloride (NaCl).

Investigating Ideal Gas Behavior and Deviations

A set of experiments was conducted to measure the pressure of an ideal gas at various temperatures.

Investigation of Gas Effusion Rates in Micro-Perforated Containers

A student designs an experiment to study the effusion of a gas using a container with micro-perforat

Kinetic Molecular Theory and Root-Mean-Square Speed

Argon gas (molar mass = 39.95 g/mol) at 298 K is contained in a vessel. Answer the following:

Lattice Energy and Melting Points

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

Non-Ideal Gas Behavior Analysis

Compare experimental gas pressures with predictions from the ideal gas law and explain the factors c

Paper Chromatography Analysis

A researcher employs paper chromatography to separate the components of an ink mixture. Using the pr

Pressure, Temperature, and Gas Behaviors

Analyze how pressure and temperature affect gas behavior and deviations from ideal behavior.

Analysis of Changes in Oxidation States in Redox Reactions

Consider the redox reaction: $$Fe + 2*HCl \rightarrow FeCl_2 + H_2$$.

Analysis of Reaction Process Diagram

A schematic diagram is provided that represents an experimental setup for a redox reaction process.

Balancing Chemical Equations and Stoichiometric Calculations

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

Chemical Equilibrium in Acid-Base Reactions

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

Complex Ion Formation: Analysis of Oxidation States

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

Determination of Oxidation States

Assign oxidation states to the elements in the following compounds:

Determination of Unknown Concentration via Redox Titration

A redox titration is performed in which a known concentration of potassium permanganate (KMnO₄) solu

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

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 13: Balancing Complex Redox Reactions

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

Gravimetric Analysis for Alkali Hydroxide Identification

An unknown alkali hydroxide compound sample weighing 4.33 g is dissolved in water and reacted with a

Gravimetric Analysis of Alkali Hydroxides

A 4.33 g sample of an unknown alkali hydroxide is dissolved completely in water. A sufficient soluti

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

Kinetics in a Redox Reaction with Temperature Variations

A student investigates the kinetics of a redox reaction between a metal ion and a reducing agent by

Monitoring a Decomposition Reaction Using Gas Volume

A student observes a decomposition reaction that produces a gas by measuring the gas volume at regul

Precipitation Reaction: Solubility Product and Reaction Prediction

In an aqueous solution, the formation of a precipitate is predicted by comparing the ionic product Q

Redox Reaction and Oxidation States

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

Redox Titration Kinetics and Concentration Determination

In a redox titration experiment using $$KMnO_{4}$$, the progress of the titration is monitored by me

Redox Titration with Permanganate

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

Redox Titration: Determination of Iron(II) Concentration

A student performs a redox titration to determine the concentration of an iron(II) sulfate solution

Redox Titration: Determining the Concentration of an Oxidizing Agent

A redox titration experiment is performed to determine the concentration of an unknown Fe2+ solution

Redox Titration: KMnO4 and Oxalate Reaction

A student performs a redox titration using potassium permanganate ($$KMnO_4$$) as the titrant to det

Sequential Reactions: Decomposition and Neutralization

Compound XY decomposes upon heating into element X and diatomic gas Y2. The gas Y2 is then bubbled t

Stoichiometric Calculations in Combustion Analysis

A 2.00 g sample of an unknown organic compound containing only carbon, hydrogen, and oxygen is compl

Synthesis Reaction: Production of Compound AB

A chemist is designing a synthesis reaction to produce compound $$AB$$ by combining pure element $$A

Synthesis Reaction: Yield Optimization Analysis

A series of experiments were conducted to synthesize compound AB by reacting reactants A and B in di

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

Analysis of a Reaction Energy Profile Diagram

An energy profile diagram of a chemical reaction is provided, which shows the energy levels of react

Analyzing Second-Order Reaction Kinetics

A reaction is known to follow second-order kinetics with respect to reactant A. Answer the following

Arrhenius Plot Analysis

Arrhenius plots are a common graphical tool used to determine activation energy. Answer the followin

Arrhenius Plot and Activation Energy Determination

The Arrhenius equation relates the rate constant $$k$$ to temperature $$T$$ and activation energy $$

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

Catalyst Impact on Reaction Rate and Energy Profile

Catalysts are known to affect reaction rates by providing alternative reaction pathways. Analyze the

Collision Theory and Reaction Rates

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

Comparative Analysis of Reaction Orders Based on Experimental Data

Three different experiments are provided, each believed to represent a reaction with zero-, first-,

Computer Simulation in Kinetic Studies

A computer simulation of a chemical reaction provides concentration vs. time curves for the reaction

Derivation and Application of the First-Order Integrated Rate Law

Consider the unimolecular decomposition of substance A that follows first-order kinetics. Answer th

Derivation of Overall Rate Law Using the Steady-State Approximation

Consider the reaction $$D \rightarrow E$$ that follows a two-step mechanism: Step I (fast): $$D \ri

Determination of Activation Energy Using the Arrhenius Equation

A chemist conducted experiments to study the temperature dependence of a reaction. The following dat

Determining Reaction Order from Initial Rate Data

A chemist investigates the reaction $$A + 2*B + C \rightarrow D$$. The following data were collected

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

Enzyme Kinetics and the Michaelis-Menten Equation

An enzyme catalyzes the conversion of substrate S to product P. The following experimental data for

Exploring Reaction Temperature Effects Using Arrhenius Plots

A series of experiments were conducted to measure the rate constant $$k$$ of a reaction at different

Graphical Analysis of a Second-Order Reaction

A reaction is believed to follow second-order kinetics with respect to reactant A. The integrated ra

Identifying and Explaining Intermediates in Reaction Mechanisms

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

Identifying Reaction Order from Graphical Data

Three different graphs representing concentration versus time for a reactant A are provided in the s

Investigating the Effect of a Catalyst on Reaction Rate

In the reaction $$A + B \rightarrow C$$, the addition of catalyst X is found to double the rate at w

Investigation of Kinetic Isotope Effects on Reaction Rates

An experiment is designed to compare the reaction rates of a compound and its deuterated analogue. A

Kinetic Competition in Parallel Reaction Pathways

In a reaction where A + B can proceed via two parallel pathways to form product C, each pathway has

Kinetics of a Catalyzed Reaction

Catalysts can significantly alter the rate of reactions without being consumed. Consider the reactio

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

Application of Hess’s Law

A reaction can be carried out in a series of steps. Consider the following steps: Step 1: $$A \righ

Bond and Formation Enthalpy Combined Analysis

A hypothetical reaction involves the breaking and forming of chemical bonds and can also be analyzed

Catalyst Effect on Reaction Mechanism

A reaction can proceed by two pathways: one with a catalyst and one without. The energy diagram show

Catalyst Effects on Reaction Mechanisms

This FRQ explores how catalysts influence reaction kinetics by lowering activation energy without af

Catalyst Impact on Reaction Mechanism

A new catalyst is reported to modify the reaction pathway, leading to a lower activation energy whil

Comparing Specific Heat Capacities of Different Substances

A study measures the specific heat capacities of three substances with the following data: | Substa

Designing an Experiment to Measure Enthalpy Change of Fusion

A researcher aims to measure the enthalpy change of fusion for a solid substance, such as tin. The e

Determination of Enthalpy of Formation from Experimental Data

Experimental data has been collected to study the formation of compound X from its elements. The for

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

Energy Profiles of Reversible Reactions

Analyze the energy diagram for a reversible reaction provided in the stimulus. The diagram shows bot

Enthalpy of Formation Calculations

Calculate the enthalpy change for the combustion reaction of carbon (graphite) to form carbon dioxid

Enthalpy of Phase Change: Melting and Vaporization

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

Enthalpy of Solution

When an ionic compound dissolves in water, the process involves breaking ionic bonds, disrupting wat

Environmental Impact of Exothermic Discharge in a Lake

A student investigates the thermal impact of an industrial exothermic discharge on a small lake. The

Evaluating Enthalpy Changes in Multi-step Reactions via Hess's Law

A complex reaction can be broken down into three steps with the following enthalpy changes: Step 1:

Frictional Heating and Energy Conversion

In a friction experiment, a block slows down as it slides along a surface and its temperature increa

Heat and Temperature: Conceptual Distinctions

Heat and temperature are often confused despite being distinct concepts. Using your understanding of

Heat Transfer Mechanisms

Heat can be transferred by conduction, convection, and radiation. Explain each mechanism and design

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

Investigating the Effect of Temperature on Reaction Rate in Catalyzed Reactions

This question explores the influence of temperature on the rate of a catalyzed chemical reaction. Th

Kinetic Energy and Heat Transfer

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

Modeling Energy Changes Using Calorimetric Data

A calorimetry experiment provided the following data: | Parameter | Value | |-----

Phase Change and Spontaneity: Sublimation vs. Deposition

This FRQ explores the thermodynamics of phase changes, focusing on sublimation and deposition, and d

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

Thermodynamics in Atmospheric Pressure Variations

A reaction is performed at both sea level (1 atm) and at a high-altitude location (0.8 atm). Conside

Vaporization and Condensation: Energy Considerations

A researcher examines the phase change of water as it vaporizes and then condenses. The enthalpy of

Acid-Base Equilibria: Understanding Ka and Kb

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

Analyzing Concentration vs. Time Graph for an Equilibrium Reaction

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

Calculating Q for a Complex Reaction

For the reaction $$2*A + B \leftrightarrow 3*C + D$$, use the following data to calculate the reacti

Common Ion Effect on Solubility of AgCl

Consider the dissolution of silver chloride according to the equation $$AgCl(s) \leftrightarrow Ag^+

Concentration Changes in Aqueous Equilibria

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

Decomposition of PCl5: Misinterpretation of Pressure Effects

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

Designing an Experiment on the Common Ion Effect in AgCl Solubility

Silver chloride (AgCl) is sparingly soluble in water. When a salt containing a common ion, such as N

Designing an Experiment to Study Precipitation Using Ksp and Common Ion Effect

You aim to study the solubility of silver bromide (AgBr) by determining its $$K_{sp}$$. Design an ex

Determination of Ksp from Molar Solubility for Salt XY₂

Salt XY₂ dissolves in water according to the equilibrium $$XY_{2} (s) \rightleftharpoons X^{2+} (aq)

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

Determining the Reaction Quotient in an Aqueous Equilibrium Reaction

For the equilibrium reaction: $$M(aq) + N(aq) \rightleftharpoons P(aq)$$, the system is not initiall

Dilution Effects on Aqueous Equilibria

Consider the equilibrium reaction for the formation of the complex ion in the system: $$Fe^{3+}(aq)

Dilution Effects on Aqueous Equilibrium

For the equilibrium reaction $$Fe^{3+}(aq) + SCN^{-}(aq) \leftrightarrow FeSCN^{2+}(aq)$$, answer th

Dynamic Equilibrium and Reaction Quotient Analysis

For the reaction: $$2M(g) \rightleftharpoons N(g) + 3O(g)$$, at a given moment, the concentrations a

Dynamics of Water Ionization and Determination of $$K_w$$

Design an experiment to measure the ionization of water and determine the value of the water ionizat

Effect of Dilution on Chemical Equilibrium

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

Effect of Inert Gas Addition at Constant Volume vs. Constant Pressure

A researcher investigates the effect of adding an inert gas to the equilibrium system of the reactio

Effect of Inert Gas on Equilibrium at Constant Volume vs Constant Pressure

For the equilibrium reaction: $$2D \rightleftharpoons E$$, an inert gas is added to the system under

Effect of Temperature on Keq

Consider an exothermic reaction with $$\Delta H = -100\, kJ/mol$$. Experimental measurements yielded

Effects of Dilution on Acid-Base Equilibrium

Consider the acid-base equilibrium: $$\rm H^{+}(aq) + A^{-}(aq) \rightleftharpoons HA(aq)$$. A solut

Environmental Chemistry and Solubility Equilibria

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

Equilibrium Constant Manipulations via Hess’s Law

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

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

Graphical Analysis of Equilibrium Data

A researcher recorded the concentration of a reactant over time in a closed reaction system. A graph

Graphical Analysis of Equilibrium Shifts

A chemist monitors the reaction $$\mathrm{A + 2B \rightleftharpoons C}$$ over time. The graph provid

Graphical Analysis of Reaction Equilibria

A study investigates the simple reaction $$A \rightleftharpoons B$$. The concentration of A decrease

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

Haber Process Equilibrium Analysis

The Haber process converts N₂ and H₂ into NH₃ in a reversible reaction. Analyze the provided graph f

Hess's Law and Composite Equilibria

Consider the following reactions with their respective equilibrium constants: (1) $$A (g) \rightlef

Hess’s Law and Constant Manipulation

Consider the following reactions: (a) $$M \rightleftharpoons N$$ with $$K_a = 2.5$$ (b) $$N \rightle

Influence of External Pressure on Gaseous Equilibria

Design an experiment to investigate the effect of external pressure changes on the equilibrium of th

Investigating Temperature Effects on Aqueous Equilibria

An experiment to study the effect of temperature on the equilibrium of the reaction $$C + D \rightle

Kinetics vs. Equilibrium Analysis

In a reaction experiment, it was observed that the reaction rate decreases over time until a constan

Le Chatelier’s Principle in Industrial Applications

In the Haber process for ammonia synthesis ($$N₂ + 3H₂ \rightleftharpoons 2NH₃$$), process condition

Le Chatelier's Principle Under Mixed Conditions

For the equilibrium reaction: $$\mathrm{PCl_{5} (g) \rightleftharpoons PCl_{3} (g) + Cl_{2} (g)}$$,

Manipulation of Equilibrium Constants via Reaction Reversal and Scaling

For the reaction: $$A+B ⇌ C$$, a researcher knows that the equilibrium constant $$K$$ is 8.0. Answer

Multi-step Equilibrium Manipulations

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

Pressure Effects on Equilibrium Dynamics

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

Pressure Effects on Gaseous Equilibria

The reversible reaction $$\text{PCl}_5 \leftrightharpoons \text{PCl}_3 + \text{Cl}_2$$ involves gase

Pressure Effects on Gaseous Equilibrium in the Haber Process

For the synthesis of ammonia $$N_2 + 3*H_2 \leftrightarrow 2*NH_3$$, consider how pressure changes a

Reaction Quotient Calculations for NO and NO2

For the equilibrium reaction: $$2NO (g) + O_2 (g) \rightleftharpoons 2NO_2 (g)$$, consider the initi

Techniques for Determining Solubility Product, Ksp

In a series of experiments, a sparingly soluble salt, $$MX_2$$, dissociates as $$MX_2(s) \rightlefth

Temperature Effects on Equilibrium

For the exothermic reaction $$A + B \leftrightharpoons C + D + \text{energy}$$, answer the following

Temperature Effects on Equilibrium Constants

Examine how temperature variations affect the equilibrium constants for both exothermic and endother

Temperature Effects on Exothermic Equilibrium Reactions

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

Visual Analysis of Equilibrium Diagram

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

Acid Rain and Lake pH Analysis

A lake near a manufacturing region has experienced several acid rain events over a five day period.

Autoionization of Water and pH Limits

Derive the classical relationship for water autoionization and discuss why pH values might fall outs

Automated pH Meter Calibration and Verification

Accurate pH measurements are essential in acid-base experiments. Answer the following:

Buffer Capacity Optimization Experiment

A researcher is investigating how different buffer concentrations influence buffer capacity. The goa

Buffer Solution pH Analysis

This FRQ addresses the behavior of buffer solutions by examining the relationship between the acid a

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 Laboratory Experiment for a Weak Acid

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

Determining pH of a Weak Base Solution

A 0.1 M solution of ammonia (NH₃) in water partially ionizes according to the equilibrium $$\text{NH

Effect of Dilution on the Ionization of a Weak Acid

A 0.1 M solution of acetic acid (HC₂H₃O₂) is diluted to 0.01 M. Consider how the dilution affects th

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

Hydrolysis of Salt: pH Calculation for Sodium Acetate

Sodium acetate (NaC₂H₃O₂) is a salt that, when dissolved in water, undergoes hydrolysis according to

Indicator Selection in Titration of Weak Acid with Weak Base

Titrations involving weak acids and weak bases may present ambiguous end points due to gradual pH ch

Investigation of pH Fluctuations in Electrochemical Cells

An electrochemical cell exhibits significant pH fluctuations during operation due to concurrent acid

Kinetics in Acid–Base Neutralizations

A reaction between a strong acid (HCl) and a weak base (NH₃) is being studied. The reaction is assum

Neutralization Reaction and Buffer pH Control

A buffer solution is prepared by mixing a weak acid with its conjugate base. Using the Henderson–Has

pKa, pKb, and Their Relationship in Acid-Base Equilibria

The relationship between $$pK_a$$ and $$pK_b$$ for a conjugate acid-base pair is a fundamental conce

Predicting Solubility Using pH and the Common Ion Effect

Using $$Mg(OH)_2$$ as an example, answer the following:

Role of Weak Bases in Buffer Systems

Weak bases are often used in buffer systems to help maintain pH stability. Address the following:

Solubility and pH: Equilibrium Manipulation

A lab experiment investigates how changing the pH of a solution affects the solubility of Mg(OH)₂. U

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

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

Assessing the Effect of Concentration on Equilibrium and Electrochemistry

The following table shows the relationship between ion concentration and measured cell voltage:

Battery Efficiency and Energy Calculations

A galvanic cell battery is tested under load with the following measurements: a current of 2.5 A, an

Comparing Spontaneity in Redox vs. Non-redox Reactions

A complex chemical process involves coupling a spontaneous redox reaction with a non-spontaneous rea

Comparing Standard to Non-Standard Conditions in Cell Voltage

A galvanic cell exhibits a cell voltage of 1.2 V under standard conditions. When the cell is operate

Designing an Experiment to Measure Gibbs Free Energy Change using a Galvanic Cell

Design a controlled experiment to determine the standard Gibbs free energy change $$\Delta G^\circ$$

Effect of Phase Change on Entropy

Consider the following two reactions: (1) $$N_2(g) + 3H_2(g) -> 2NH_3(g)$$ (2) $$SO_3(g) + H_2O(g) -

Electroplating Calculations in Electrolytic Cells

A company is using an electrolytic cell to electroplate silver onto electronic components. The proce

Entropy Calculation from Reaction Data

A researcher is investigating the change in entropy (S) for a reaction occurring under standard cond

Entropy Considerations in a Reaction with Phase Change

For the reaction $$CaCO_3(s) \rightarrow CaO(s) + CO_2(g)$$, analyze the entropy change.

Equilibrium Constant and Gibbs Free Energy

A reaction at equilibrium is characterized by an equilibrium constant (K). The relationship between

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.

Gibbs Free Energy Calculation and Reaction Analysis

A media headline claims that a certain reaction is thermodynamically favored at room temperature bec

Gibbs Free Energy under Non-Standard Conditions

An experiment examines how deviations from standard conditions affect the cell potential in an elect

Influence of Temperature on Gibbs Free Energy

Design an experiment to study how temperature affects the Gibbs free energy (ΔG°) of an endothermic

Interpreting Gibbs Free Energy from Reaction Spontaneity Reports

A study reports that a reaction with $$\Delta H° = +50\;kJ/mol$$ and $$\Delta S° = +100\;J/mol\cdot

Interpreting the Role of Reduction Potentials in Redox Reactions

The table below lists various half-reactions and their corresponding standard reduction potentials (

Redox Cell Salt Bridge Function Error

In an effort to measure the cell potential of a galvanic cell, a researcher set up a redox cell usin

Redox Reaction Analysis in a Galvanic Cell

A galvanic cell is constructed with copper and zinc electrodes. The standard reduction potentials ar

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 Effects on Electrolysis and Electroplating

In an experiment involving an electrolytic cell used for electroplating, the effects of temperature

The Nernst Equation in Concentration Cells

A concentration cell is constructed with two copper electrodes. One electrode is immersed in a 1.0 M