AP Chemistry FRQ Room

Analysis of Isotopic Impurities in Mass Spectrometry with Signal Overlap Error

A chemist performs a mass spectrometry experiment to assess the isotopic purity of a boron sample. T

Analyzing Successive Ionization Energies

An unknown element exhibits the following successive ionization energies: • First IE = $$738$$ kJ/m

Application of the Aufbau Principle in Electron Configuration

Determine an element's electron configuration using the Aufbau principle and discuss its limitations

Atomic Radius Measurement Experiment with Faulty Trend Interpretation

In an experiment to study periodic trends, a student measures the atomic radii of a series of elemen

Charge Density and Lattice Energy in Ionic Solids

The stability of ionic solids is influenced by ionic sizes and charge densities. Answer the followin

Comparative Analysis of Photoelectron Spectra for Different Elements

Two photoelectron spectra are obtained for Elements A and B. The spectrum for Element A shows narrow

Designing an Experiment to Determine Molarity

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

Effects of Electron Shielding on Ionization Energy

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

Electron Configurations and the Aufbau Principle

A researcher is investigating electron configurations in elements. Focus on an element in group 16,

Electronegativity and Bond Type Prediction

Consider two elements, A and B, with electronegativity values of $$1.2$$ and $$3.0$$ respectively. A

Electronegativity Trends Analysis

A table provides electronegativity values for elements across period 2. The hypothesis is that as yo

Empirical and Molecular Formula Calculation

This problem focuses on converting percent composition data to an empirical formula and then using t

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

Gas Law Mole Calculations and Stoichiometry

This question examines the application of the ideal gas law and stoichiometry in determining moles a

Impact of Electron Shielding on Successive Ionization Energies

A researcher evaluates the role of electron shielding in determining the energies required to remove

Ionic Charge Prediction and Compound Formation

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

Ionization Energy Determination Experiment with Overlooked Electron Screening

In an experiment to measure the ionization energy of a multi-electron atom using photoelectron spect

Limiting Reactants: Combustion of Carbon

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

Mass Spectrometry and Isotopic Abundance

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

Mass Spectrometry and Isotopic Ratios

This question explores the determination of atomic mass using mass spectrometry data and the concept

Molarity and Dilution Calculations

Solve problems involving molarity calculations and the dilution of solutions.

Molecular Formula Determination from Empirical Data

A compound is found to have a percent composition of 40% carbon, 6.7% hydrogen, and 53.3% oxygen. It

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: Experimental vs. Theoretical Analysis

A compound's percent composition was determined both theoretically and experimentally. The table bel

Periodic Trends and Atomic Structure Analysis

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

Periodic Trends and Electron Shielding

A researcher examines periodic trends, focusing on elements in period 2, to better understand atomic

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

Precipitation Reaction and Ksp Determination with Misapplied Equilibrium Assumptions

An experiment is conducted to determine the solubility product (Ksp) of silver chloride by mixing kn

Predicting Ionic Charges Based on Periodic Trends

In a reaction experiment, compounds form according to the predicted ionic charges based on periodic

Qualitative and Quantitative Analysis of Spectra Data

This integrative problem requires students to analyze complex spectral data, converting qualitative

Solution Molarity Calculations

Relate moles, grams, and volume by addressing solution concentration.

Titration and Molarity Determination with Indicator Misuse

In an experiment to determine the molarity of a hydrochloric acid solution, a student performs a tit

Analyzing Conductivity Across Bond Types

A researcher compiles data on the electrical conductivity of various compounds—ionic, molecular, net

Bond Energy and Internuclear Distance in Covalent Bonds

This question examines the relationship between bond energy and internuclear distance in covalent bo

Bond Formation and Stability: Investigating Covalent Networks

This question examines how the network covalent structure contributes to the thermal stability of co

Comparing Ionic, Covalent, and Metallic Bonds

Construct a comparative analysis of the physical properties of substances held together by ionic, mo

Covalent Bonding and Electron Sharing Experiment Design

This question explores differences in bonding in molecules with single, double, and triple bonds and

Determining Molecular Polarity and Intermolecular Forces

This question investigates how molecular geometry and electronegativity differences lead to polarity

Effect of Expanded Octets on Molecular Structure: $$\text{PCl}_5$$ and $$\text{SF}_6$$

This question explores the concept of expanded octets by requiring drawing Lewis structures for $$\t

Electrical Conductivity in Various Bonded Structures

Analyze how the type of chemical bonding influences electrical conductivity in different phases.

Electronegativity and Bonding Character Analysis

A study claims that the percentage ionic versus covalent character of a bond can be accurately deter

Expanded Octets in Main Group Elements

Some main group elements can form expanded octets by utilizing available d orbitals. Explore this ph

Formal Charge Distribution in Sulfur Trioxide (SO₃)

The stable configuration of molecules can often be predicted by formal charge calculations. Examine

FRQ 10: Bonding and Electrical Conductivity Across Phases

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

FRQ 14: Bonding Effects on Melting Points in Metallic Alloys

A table compares the melting points of pure metals and their corresponding alloys. In your answer, (

FRQ 18: Predicting Molecular Geometry from Hybridization

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

FRQ4: Lewis Dot Structures and Formal Charges of the Carbonate Ion

The carbonate ion ($$CO_3^{2-}$$) exhibits resonance, which affects its bond characteristics. Answer

Interatomic Potential Energy and Internuclear Distance

A graph displays the potential energy (in kJ/mol) as a function of internuclear distance (in Å) for

Ionic Bond Strength Comparison

A materials scientist is investigating the factors that affect the lattice energy of ionic compounds

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 Comparison

Consider several ionic compounds such as NaCl, MgO, and Al2O3. Each compound is composed of ions wit

Kinetic Analysis in Gas-Phase Reactions with Collisional Theory Error

A researcher examines the kinetics of a gas-phase reaction involving a covalent molecule by measurin

Limitations of Lewis Structures and Insights from Molecular Orbital Theory

This question asks for a critical evaluation of Lewis dot structures in describing the bonding in $$

Metallic Bonding and Alloy Formation

This question examines the nature of metallic bonds and the formation of alloys. You will need to ex

Metallic Bonding and Alloy Formation: Structural Considerations

This question focuses on metallic bonding and how it enables the formation of different types of all

Network Covalent Bonding and Material Properties

This question explores the distinctive characteristics of network covalent solids and how their bond

Polarity and Shape: The Case of Water Molecule

Water ($$H_{2}O$$) is a polar molecule largely due to its bent geometry. Answer the following:

Real-World Alloy Analysis: Conductivity and Strength in Brass

Brass, an alloy of copper and zinc, displays different electrical and mechanical properties compared

Resonance and Bond Order in Carbonate Ion

The carbonate ion (CO3²⁻) exhibits resonance, meaning that its Lewis structure can be represented by

Resonance and Bond Order in the Carbonate Ion

The carbonate ion (CO3^2-) is known to exhibit resonance. Answer the following questions using reson

Resonance and Bond Order in the Carbonate Ion

The carbonate ion $$CO_{3}^{2-}$$ exhibits resonance, resulting in fractional bond orders for the C-

Resonance Structures and Bond Order in Carbonate Ion

Analyze the resonance in the carbonate ion $$CO_3^{2-}$$ and its implications for bond order.

Assessment of Phase Transition Analysis Based on Intermolecular Forces

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

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

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

Dalton's Law of Partial Pressures

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

Dalton's Law of Partial Pressures in Gas Mixtures

This question focuses on Dalton's Law and its application in gas mixtures.

Density and Molar Mass Calculation of Gases

Analyze the relationship between density and molar mass in gases and use this relationship to identi

Determination of Boiling Points in Mixtures with Azeotropic Behavior

A student designs an experiment to determine the boiling point of a liquid mixture by distillation.

Deviation from Ideal Behavior at High Pressures

When gases are compressed to very high pressures, deviations from ideal gas behavior become signific

Distillation and Phase Change Analysis

This question examines the relationship between intermolecular forces and phase changes, particularl

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

Hydrogen Bonding in Water vs. Ammonia

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

Ideal Gas Behavior: Real vs. Ideal

A college laboratory experiment measures the pressure of a gas in a fixed 10 L container at various

Ideal Gas Law and Stoichiometry

A 10.0 L container is said to hold a mixture of three gases at 1.00 atm and 298 K: 0.50 mol of hydro

Intermolecular Forces and Distillation Analysis

A mixture contains two liquids, A and B. Liquid A exhibits hydrogen bonding and has a boiling point

Intermolecular Forces and Vapor Pressure: A Multi-Phase Analysis

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

Lattice Energy and Melting Points

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

London Dispersion Forces and Molecular Size Relationship

London dispersion forces (LDFs) are weak intermolecular forces present in all molecules, but their s

Molecular Geometry and Polarity Exceptions

This question asks you to analyze how molecular geometry and the presence of lone pairs affect molec

Molecular Polarity and Bonding Effects

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

Spectrophotometric Analysis in Reaction Kinetics with Calibration Mismatch

A student monitors the progress of a colorimetric reaction using a spectrophotometer by measuring th

Balancing Half-Reactions in Redox Processes

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

Comparative Analysis of Reaction Types

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

Determination of Oxidation States in Compounds

For the following compounds, assign oxidation states to all elements and justify your assignments: (

Gravimetric Method for Determining Ion Concentration

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

Gravimetric Precipitation of an Unknown Carbonate

A student performs a gravimetric analysis to determine the carbonate content in an unknown mineral s

Half-Reaction Balancing in a Redox Reaction Involving Polyatomic Ions

In acidic solution, chloride ions are oxidized to chlorine gas, and permanganate ions are reduced to

Integration of Reaction Types: From Synthesis to Redox

An industrial process involves two sequential reactions. First, a synthesis reaction produces compou

Investigating Synthesis Reaction Efficiency

A synthesis reaction combines reactants A and B to form product AB. Design an experiment to investig

Limiting Reactant Determination in Hydrocarbon Combustion

Butane (C₄H₁₀) undergoes complete combustion according to the equation: $$2*C_4H_{10} + 13*O_2 \rig

Misinterpretation in Oxidation State Determination

A student conducts an experiment to determine the oxidation states of elements in transition metal c

Monitoring a Decomposition Reaction Using Gas Volume

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

Percent Error Analysis in Reaction Yield

In three separate reaction trials, the experimental yield and theoretical yield were recorded. Revie

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

Precipitation Reaction and Solubility Rules

In an experiment involving the mixing of various aqueous salt solutions, a researcher observes the f

Precipitation Reaction and Solubility Rules

A solution of 0.100 M $$Na_2SO_4$$ is mixed with 0.100 M $$BaCl_2$$. The reaction that occurs is the

Reaction Kinetics in Decomposition of Hydrogen Peroxide

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

Redox Reaction and Oxidation States

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

Redox Titration Data Analysis

A redox titration experiment is conducted using potassium permanganate (KMnO4) as an oxidizing agent

Redox Titration Kinetics and Concentration Determination

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

Thermochemical Considerations in Synthesis and Decomposition

A synthesis reaction releases $$\Delta H = -200\,kJ$$ while a decomposition reaction absorbs $$\Delt

Writing and Balancing Redox Reactions

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

Analysis of Multi-step Reaction Mechanisms and Rate-Determining Step

Consider a reaction that proceeds by the following elementary steps: I. $$A + A \to X$$ (fast) II.

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

Analyzing Reaction Mechanisms and Intermediates

Consider the following proposed mechanism for the reaction: Step I (fast): A + A → X Step II (slow)

Arrhenius Equation and Activation Energy Determination

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

Arrhenius Plot Analysis

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

Catalyst Impact on Reaction Kinetics

A reaction involving $$A + B \rightarrow C$$ can be catalyzed by the addition of a substance X. Cons

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 Temperature Effects

Collision theory explains how reaction rates depend on the energy and orientation of colliding molec

Collision Theory: Effects of Concentration and Temperature

Collision theory explains many aspects of how reaction rates change. Answer the following parts.

Comparison of Reaction Mechanisms

Two different mechanisms have been proposed for the reaction $$A + 2*B \rightarrow C$$. One mechanis

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

Designing an Experiment to Determine a Reaction's Rate Law

You are tasked with determining the rate law for the reaction $$X + Y \rightarrow Z$$. Design an exp

Designing an Experiment to Investigate the Effect of Temperature on Reaction Rates

A chemist is designing an experiment to study how temperature affects the reaction rate of the react

Determining Rate Law from Initial Rates Experiment

A series of experiments were conducted on the reaction $$A + 2B + C \rightarrow D$$. The following t

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 the Rate Constant for a First-Order Reaction Using Graphs

A first-order reaction is monitored by measuring the natural logarithm of the concentration of react

Development of a Pseudo-First Order Rate Law

Consider the reaction $$A + B \rightarrow C$$, where B is present in large excess. Under these condi

Energy Profile Diagram Misinterpretation in Exothermic Reactions

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

Explaining the Role of Molecular Orientation in Collision Theory

Explain, using collision theory, how molecular orientation influences the likelihood of a successful

Graph Interpretation of Competing Reaction Pathways

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

Integrated Rate Law Analysis for a Second Order Reaction

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

Integrated Rate Law for a First-Order Reaction

An experiment was performed on a reaction believed to be first order. The integrated rate law for a

Investigating the Effect of Pressure on Gas-Phase Reaction Rates

A chemist investigates the decomposition of a gaseous compound by varying its pressure while keeping

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

Quantitative Analysis of a Zero-Order Reaction

A chemical reaction was found to follow zero-order kinetics with respect to reactant D. The concentr

Unit Consistency Error in Calculating Rate Constants from Initial Rates

An experiment was performed to calculate the rate constant $$k$$ using the equation $$k = \frac{rate

Zero-Order Kinetics and Data Sufficiency: Misclassification Due to Insufficient Data

In an experiment aimed at determining the reaction order, a student plotted the concentration of rea

Analysis of a Water Freezing Curve

A cooling curve of water shows supercooling before freezing. Answer the following:

Analyzing Enthalpy Diagrams of Reactions

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

Analyzing Environmental Impact of Endothermic Processes

An industrial facility employs an endothermic reaction to capture carbon dioxide from emissions, whi

Analyzing Thermodynamic Data for Reaction Feasibility

A study claims that the measured enthalpy change (ΔH) of a reaction alone can predict its spontaneit

Bomb Calorimetry and Reaction Enthalpy Determination

Bomb calorimetry is used to accurately measure the enthalpy change of combustion reactions. Explain

Bond Energy and Reaction Mechanism Investigation

The reaction below is provided for analysis: $$CH_4(g)+2*O_2(g)\rightarrow CO_2(g)+2*H_2O(l)$$ Usi

Bond Energy Calculations for Reaction Enthalpy

A chemist is estimating the enthalpy change for the reaction: $$\text{H}_2 (g) + \text{Cl}_2 (g) \ri

Bond Energy Calculations in a Reaction

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

Bond Energy vs. Enthalpy of Formation Calculations

A report claims that calculating reaction enthalpy using bond energies yields the same result as usi

Calculating Reaction Enthalpy Using Hess's Law

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

Calorimetry and Specific Heat Calculation

A student conducts an experiment using a calorimeter to measure the specific heat of an unknown meta

Calorimetry in Action

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

Calorimetry in Reaction Enthalpy Determination

In a calorimetry experiment, an insulated container holds 150.0 g of water. A reaction causes the wa

Calorimetry of an Aqueous Reaction

An aqueous reaction was carried out using a coffee-cup calorimeter. A 120.0 g solution experienced a

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

Catalysts and Their Role in Energy Diagrams

Catalysts are known to alter the energy diagram of a chemical reaction by lowering the activation en

Comparative Study of Enthalpies of Formation for Organic Compounds

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

Comparing Specific Heat Capacities of Different Substances

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

Comparing Theoretical and Experimental Enthalpy Changes

A reaction was studied using both theoretical bond energy calculations and experimental calorimetry.

Determining Unknown Reaction Enthalpy Using Hess’s Law

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

Energy Diagrams and Reaction Enthalpy

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

Enthalpy of Formation and Reaction Stability

The standard enthalpies of formation ($$ΔH_f°$$) for compounds are provided in the following table:

Enthalpy of Formation and Reaction Stability

Methanol can be formed from its elements according to the reaction: $$C(s) + \frac{1}{2} O_2(g) + 2

Enthalpy of Solution and Hydration Energy

When an ionic salt dissolves in water, energy changes occur due to both lattice dissociation and hyd

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:

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

First Law of Thermodynamics and Calorimetry Data

A reaction conducted in a calorimeter releases 250 J of heat and does 50 J of work on the surroundin

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 Enthalpy of Solution for an Ionic Compound

A researcher dissolves 5.00 g of sodium chloride (NaCl) in water and observes a temperature change.

Kinetic Energy and Heat Transfer

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

Modeling Energy Diagrams for Endothermic Reactions

In a study of an endothermic reaction, researchers use temperature measurements to construct an ener

Phase Change Thermodynamics: Enthalpy of Fusion and Vaporization

A substance with a molar mass of $$18 \; g/mol$$ undergoes melting. Its enthalpy of fusion is $$6.0

Thermodynamic Analysis of Bond Formation and Breaking

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

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 Equilibrium Analysis

Consider the dissociation of a weak acid, HA, in water given by: $$HA(aq) \rightleftharpoons H^+(aq)

Application of Reaction Quotient (Q) in Determining Equilibrium Shift

For the reaction $$SO_2 + H_2O \leftrightharpoons H_2SO_3$$, answer the following parts.

Complex Equilibrium Stoichiometry: Error Analysis in Multi-Component System

A researcher studies the equilibrium of the reaction $$2A + B \rightleftharpoons 3C + D$$ by sequent

Computational Equilibrium Constant Derivation

Given the following reactions and their equilibrium constants: Reaction A: $$D \rightleftharpoons E$

Determining $$Keq$$ from Experimental Data

A reaction $$D + E \rightleftharpoons F + G$$ is monitored over time. A graph of the concentrations

Determining Ksp from Molar Solubility Data

Consider a salt, $$AB_2$$, that dissolves according to the equation: $$AB_2 (s) \rightleftharpoons A

Dynamic Equilibrium and Reaction Rates

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

Equilibrium Constant Manipulations via Hess’s Law

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

Equilibrium Manipulations via Hess's Law

Consider the following reactions: (i) $$\ce{A -> B}$$ with equilibrium constant $$K_1$$ (ii) $$\ce{B

Evaluating Experimental Design in Equilibrium Studies

A research team conducts an experiment to examine the effects of varying pollutant concentrations on

Evaluating the Effect of Catalyst on Equilibrium

Although a catalyst increases the rate at which equilibrium is reached but does not affect the equil

Experimental Determination of $$K_c$$ for HI Decomposition

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

Graphical Analysis of Equilibrium Approach

A graph showing the concentration versus time for a reversible reaction is provided. The graph displ

Graphical Analysis of Equilibrium Shifts Under External Stress

A graph displays the concentration of species versus time for a reversible reaction that has been pe

Impact of Dilution on an Aqueous Equilibrium

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

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

Inert Gas Effects on Equilibrium

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

Kinetics vs Equilibrium in a Multi-step Reaction

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

Manipulation of Equilibrium Constants via Hess's Law

Given the following reactions with their equilibrium constants: Reaction 1: $$\mathrm{A \rightlefth

Precipitation Reaction Analysis: Mixing of Solutions

A solution of 0.050 M Na$_2$SO$_4$ is mixed in equal volumes with a 0.10 M BaCl$_2$ solution. Barium

Quantitative Reaction Quotient

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

Reaction Quotient (Q) Evaluation

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

Reaction Quotient Analysis in a Perturbed System

For the reaction $$L + M \leftrightarrow N$$, initial concentrations are provided in the table below

Reaction Quotient and Equilibrium Shift Analysis

For the reaction $$N_2 + 3*H_2 \leftrightarrow 2*NH_3$$, at a certain moment the concentrations are

Reaction Quotient and Equilibrium Shift Analysis

Design an experiment to investigate the relationship between the reaction quotient (Q) and the equil

Simultaneous Effects on Equilibrium

Consider the equilibrium reaction: $$2X(g) + Y(g) \rightleftharpoons 3Z(g)$$ A system at equilibrium

Simultaneous Equilibria Analysis

A solution is governed by two simultaneous equilibria: (1) $$X \rightleftharpoons Y + Z$$ (2) $$Z +

Solubility Product and Precipitation Prediction

For the dissolution reaction of lead(II) chloride: $$\mathrm{PbCl_{2} (s) \rightleftharpoons Pb^{2+}

Temperature Effects on Equilibrium

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

Temperature Effects on the Haber Process

A researcher studies the impact of temperature on the reversible exothermic reaction of ammonia synt

Using a Graph to Extract Equilibrium Data

A reversible reaction is monitored over time with product concentrations recorded. Answer the follow

Volume Change Error in $$H_2S$$ Equilibrium Reaction

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

Buffer Capacity and pH Stability

A buffer solution is prepared by mixing a weak acid and its conjugate base. Consider a buffer system

Buffer Capacity Optimization Experiment

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

Buffer Design for pH Control

Design a buffer solution with a specific target pH and explain how the buffer resists changes in pH

Buffer pH Calculation: Misuse of the Henderson–Hasselbalch Equation

A student set out to prepare a buffer solution using acetic acid and sodium acetate. In the process,

Calculating pH of Salt Solutions

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

Common Ion Effect on Solubility

Consider the equilibrium $$\text{Mg(OH)}_2 (s) \rightleftharpoons \text{Mg}^{2+} (aq) + 2 \; \text{O

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

Error in Determining Equilibrium Constants from pH Data

A student attempted to determine the acid dissociation constant (Ka) of a weak acid by measuring the

Evaluating Neutralization Reactions: Strong vs. Weak Bases and Acids

Consider the following neutralization reactions: 1) HCl reacting with NH₃, 2) HCl reacting with NaOH

Impact of Common Ion Effect on Salt Solubility

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

Impact of Temperature on Kw and pH of Water

This FRQ investigates how changes in temperature affect the ionization of water, as evidenced by var

Indicator pKa and Color Change in Titrations

This question explores how acid-base indicators function by linking their pKa to the pH at which a c

Indicator Selection and Color Change Analysis in Titrations

In a series of titration experiments involving a weak acid and a strong base, different pH indicator

Influence of Dilution on Weak Acid Dissociation

A researcher investigates how diluting a 0.05 M solution of a weak acid affects its percent dissocia

Influence of Molecular Structure on Oxoacid Acidity

Oxacid strength can be influenced by molecular structure. Consider oxoacids such as HClO, HClO2, and

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 Analysis

Compare the reaction mechanisms and outcomes for the following neutralization reactions: (1) Strong

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

Polyprotic Acid Titration Analysis

Phosphoric acid ($$H_3PO_4$$) is a polyprotic acid with three dissociation steps. Its dissociation c

Polyprotic Acid Titration and Stepwise Dissociation

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

Relationship Between Molecular Structure and Acid Strength

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

Selecting Appropriate Indicators for Different Titrations

The choice of an indicator is critical in titrations, and it depends on the nature of the acid-base

Sequential Neutralizations in a Mixed Acid System

A solution contains a mixture of a strong acid and a weak acid. The mixture is titrated with a stron

Titration Curve Analysis of a Weak Acid with a Strong Base

A titration is performed by slowly adding a strong base to a solution of a weak acid. The resulting

Titration of Strong Acid with Weak Base: Analyzing the Half-Equivalence Point

When titrating a strong acid with a weak base, the titration curve has unique features. Address the

Weak Acid Dissociation and Percent Dissociation

This question examines the dissociation of weak acids and the concept of percent dissociation using

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

Weak Acid-Strong Base Titration Analysis

A titration is performed by titrating 30.0 mL of 0.10 M acetic acid (HC2H3O2) with 0.10 M NaOH. The

Assessing the Effect of Concentration on Equilibrium and Electrochemistry

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

Battery Design and Electrode Selection

A battery designer is considering different electrode materials with the following standard reductio

Calculating Moles Electrolyzed in a Process

An electrolytic cell is operated at a constant current to deposit silver. The cell runs at 5.00 A fo

Cell Potential and Equilibrium Constant Calculation Error

An experiment was conducted to determine the equilibrium constant (K) for a redox reaction by first

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 a Multi-step Redox Reaction Experiment

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

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 Partial Pressure on Cell Potential

Consider a gas-phase redox reaction in a galvanic cell where the partial pressure of a gaseous react

Electrolysis and Electroplating Calculation

In an electroplating experiment, metal X (molar mass $$50.0\,g/mol$$, valence +2) is deposited on a

Electroplating Calculations

An electroplating experiment is conducted to deposit a thin metal layer onto an object using a const

Entropy Change Calculation and Interpretation

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

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 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

FRQ 8: Entropy Change Due to Mole Change and Phase Transition

Consider the reaction involving the splitting of water: $$2\,H_2O(l) \rightarrow 2\,H_2(g) + O_2(g)

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

Investigating the Effect of Pressure on Reaction Entropy

Design an experiment to measure the impact of pressure on the entropy change of a gas-phase reaction

Investigation of Electrochemical Corrosion

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

Misapplication of Entropy in Free Energy Equations

A researcher conducted an experiment to evaluate the spontaneity of an exothermic reaction by calcul

Phase Diagram Misinterpretation and Thermodynamic Favorability

A researcher attempted to correlate phase diagram data with thermodynamic favorability by monitoring

Predicting Changes in Voltage Due to Variations in Conditions

A galvanic cell has an initial standard cell potential of $$E^\circ_{cell} = 1.25\,V$$ under 1 M con

Redox Reaction Mechanisms and Energy Changes

In an organic synthesis experiment, a redox reaction proceeds through multiple steps involving elect

Temperature’s Effect on Gibbs Free Energy

Consider a reaction with $$\Delta H^\circ = 60\,kJ/mol$$ and $$\Delta S^\circ = 150\,J/(mol\cdot K)$