United States · College BoardSyllabus
Chemistry syllabus, dot point by dot point
Every dot point in the United States Chemistrysyllabus, with a focused answer for each one. Click any dot point for a worked explainer, past exam questions, and links to related dot points. Written by Claude Opus 4.8, Anthropic's latest AI.
Unit 1: Atomic Structure and Properties
Module overview →- How are electrons arranged in an atom, and what rules govern that arrangement?Topic 1.5 Atomic Structure and Electron Configuration: write electron configurations for atoms and ions using the Aufbau principle, the Pauli exclusion principle, and Hund's rule, and relate them to the Coulombic model of the atom.11 min answer →
- How do we describe and calculate the composition of a mixture, as distinct from a pure compound?Topic 1.4 Composition of Mixtures: distinguish pure substances from mixtures and use elemental analysis and mass relationships to determine the composition of a mixture.9 min answer →
- How do we move between the mass of a compound, its percent composition, and its empirical and molecular formulas?Topic 1.3 Elemental Composition of Pure Substances: calculate percent composition by mass and determine empirical and molecular formulas from experimental data.10 min answer →
- How does a mass spectrum reveal the isotopes of an element and let us calculate its average atomic mass?Topic 1.2 Mass Spectra of Elements: interpret a mass spectrum to identify the isotopes of an element and their relative abundances, and calculate the average atomic mass from the data.9 min answer →
- How does the mole connect the mass of a sample to the number of particles it contains?Topic 1.1 Moles and Molar Mass: use the mole and molar mass to convert between the mass of a pure substance, the number of moles, and the number of representative particles.9 min answer →
- Why do atomic radius, ionization energy, and electronegativity change in regular patterns across the periodic table?Topic 1.7 Periodic Trends: explain and predict the trends in atomic and ionic radius, ionization energy, and electronegativity using effective nuclear charge and shielding.11 min answer →
- How does a photoelectron spectrum reveal the energies and numbers of electrons in each subshell of an atom?Topic 1.6 Photoelectron Spectroscopy: interpret a photoelectron spectrum to determine the relative energies of electrons in subshells and the number of electrons in each subshell, and relate it to electron configuration.10 min answer →
- How do valence electrons determine how an atom reacts and what ions it forms?Topic 1.8 Valence Electrons and Ionic Compounds: relate the number of valence electrons to an element's group and reactivity, and predict the ions main-group elements form and the formulas of the ionic compounds they make.9 min answer →
Unit 2: Molecular and Ionic Compound Structure and Properties
Module overview →- How does a potential-energy curve describe a covalent bond, and what controls bond length and bond energy?Topic 2.2 Intramolecular Force and Potential Energy: interpret a potential-energy versus internuclear-distance curve to define bond length and bond energy, and explain how bond order, atomic size and charge affect bond strength.10 min answer →
- How do we draw a Lewis diagram that correctly shows the bonding and lone pairs in a molecule or ion?Topic 2.5 Lewis Diagrams: draw Lewis diagrams for molecules and polyatomic ions, applying the octet rule and accounting for valence electrons, multiple bonds, and common exceptions.10 min answer →
- When several Lewis diagrams are possible, how do resonance and formal charge tell us the real structure?Topic 2.6 Resonance and Formal Charge: draw resonance structures and use formal charge to select the most reasonable Lewis diagram, and explain how resonance describes delocalised bonding.10 min answer →
- How does the lattice structure of an ionic solid explain its melting point, brittleness, and conductivity?Topic 2.3 Structure of Ionic Solids: describe the lattice of an ionic solid, relate lattice energy to ionic charge and size using Coulomb's law, and explain the properties of ionic compounds from their structure.10 min answer →
- How does the electron-sea model explain the properties of metals, and how do alloys modify them?Topic 2.4 Structure of Metals and Alloys: use the electron-sea model to explain metallic properties, and describe how interstitial and substitutional alloys change those properties.9 min answer →
- What determines whether a bond is ionic, covalent, or metallic, and how does electronegativity decide bond polarity?Topic 2.1 Types of Chemical Bonds: classify bonds as ionic, covalent (polar or nonpolar), or metallic using electronegativity and the elements involved, and relate bond type to properties.10 min answer →
- How does VSEPR predict the shape of a molecule, and how does that shape relate to hybridization and polarity?Topic 2.7 VSEPR and Bond Hybridization: use VSEPR theory to predict molecular geometry and bond angles, assign the hybridization of the central atom, and relate geometry to molecular polarity.11 min answer →
Unit 3: Intermolecular Forces and Properties
Module overview →- How does the Beer-Lambert law let us find the concentration of a colored solution from how much light it absorbs?Topic 3.13 Beer-Lambert Law: use the Beer-Lambert law to relate the absorbance of a solution to its concentration, and apply a calibration to find an unknown concentration.9 min answer →
- Why do real gases deviate from ideal behavior, and under what conditions is the deviation greatest?Topic 3.6 Deviation from Ideal Gas Law: explain why real gases deviate from the ideal gas law at high pressure and low temperature in terms of molecular volume and intermolecular forces.9 min answer →
- How does the ideal gas law relate the pressure, volume, temperature and amount of a gas?Topic 3.4 Ideal Gas Law: use the ideal gas law and its partial-pressure and gas-density forms to relate the pressure, volume, temperature and amount of a gas in calculations.10 min answer →
- What forces act between molecules, and how do their relative strengths set a substance's physical properties?Topic 3.1 Intermolecular Forces: identify and rank the intermolecular forces (London dispersion, dipole-dipole, hydrogen bonding, ion-dipole) present in a substance and relate their strength to properties such as boiling point and vapor pressure.10 min answer →
- What assumptions of kinetic molecular theory explain the behavior of an ideal gas and the shape of its speed distribution?Topic 3.5 Kinetic Molecular Theory: state the postulates of kinetic molecular theory and use them to explain gas pressure, temperature, and the Maxwell-Boltzmann distribution of molecular speeds.9 min answer →
- How does the photoelectric effect show that light is quantised into photons of energy proportional to frequency?Topic 3.12 Photoelectric Effect: explain how the photoelectric effect demonstrates that light is quantised, using the threshold frequency and the relationship between photon energy and frequency.9 min answer →
- How does the type of particle and force in a solid determine its hardness, melting point and conductivity?Topic 3.2 Properties of Solids: relate the macroscopic properties of a solid (melting point, hardness, conductivity) to its type (ionic, metallic, covalent network, molecular) and the forces holding its particles together.9 min answer →
- How do particulate diagrams represent the species actually present in a solution?Topic 3.8 Representations of Solutions: use particulate-level diagrams to represent the species present in a solution, distinguishing strong electrolytes, weak electrolytes and nonelectrolytes.9 min answer →
- How do separation techniques such as chromatography and distillation exploit differences in intermolecular forces?Topic 3.9 Separation of Solutions and Mixtures (Chromatography): explain how chromatography, distillation and filtration separate the components of a mixture by exploiting differences in their interactions and properties.9 min answer →
- How do the spacing, motion and forces of particles differ across the solid, liquid and gas states?Topic 3.3 Solids, Liquids, and Gases: describe the particle-level differences between the three states and explain how intermolecular forces and temperature determine which state a substance is in.9 min answer →
- Why does a substance dissolve in one solvent but not another, and how do temperature and pressure affect solubility?Topic 3.10 Solubility: explain solubility in terms of the intermolecular forces between solute and solvent (like dissolves like), and describe how temperature and pressure affect the solubility of solids and gases.9 min answer →
- How do we describe the composition of a solution quantitatively using molarity?Topic 3.7 Solutions and Mixtures: define solute, solvent and solution, and calculate and use molarity to relate moles, volume and concentration, including dilutions.9 min answer →
- How does the energy of electromagnetic radiation relate to its frequency, and which molecular transitions does each region of the spectrum probe?Topic 3.11 Spectroscopy and the Electromagnetic Spectrum: relate the energy, frequency and wavelength of electromagnetic radiation and identify which type of molecular transition (rotational, vibrational, electronic) each region of the spectrum probes.9 min answer →
Unit 4: Chemical Reactions
Module overview →- What macroscopic and particulate evidence tells us that a chemical reaction has occurred?Topic 4.1 Introduction for Reactions: identify the evidence that a chemical reaction has occurred and distinguish chemical changes from physical changes at the macroscopic and particle levels.9 min answer →
- How does the Bronsted-Lowry model describe acids and bases as proton donors and acceptors, and what are conjugate pairs?Topic 4.8 Introduction to Acid-Base Reactions: apply the Bronsted-Lowry model to identify acids, bases and conjugate acid-base pairs, and write acid-base reactions as proton transfers.9 min answer →
- How does a titration use a reaction of known stoichiometry to find an unknown concentration?Topic 4.6 Introduction to Titration: use titration data and reaction stoichiometry to determine the concentration of an unknown solution, distinguishing the equivalence point from the endpoint.9 min answer →
- How do we write a net ionic equation that shows only the species that actually take part in a reaction?Topic 4.2 Net Ionic Equations: write balanced molecular, complete ionic and net ionic equations for reactions in aqueous solution, removing spectator ions.10 min answer →
- How do we assign oxidation numbers, identify what is oxidized and reduced, and balance a redox reaction using half-reactions?Topic 4.9 Oxidation-Reduction (Redox) Reactions: assign oxidation numbers, identify the species oxidized and reduced and the oxidizing and reducing agents, and balance redox reactions using half-reactions.10 min answer →
- What is the difference between a physical change that affects intermolecular forces and a chemical change that breaks covalent bonds?Topic 4.4 Physical and Chemical Changes: distinguish physical changes (affecting intermolecular forces) from chemical changes (breaking and forming chemical bonds) and classify processes accordingly.9 min answer →
- How do symbolic equations and particulate diagrams represent the same reaction, and how does conservation of atoms link them?Topic 4.3 Representations of Reactions: connect symbolic, particulate and macroscopic representations of a reaction, using conservation of atoms to balance and interpret each.9 min answer →
- How do the coefficients of a balanced equation let us calculate amounts of reactants and products, including the limiting reactant?Topic 4.5 Stoichiometry: use mole ratios from a balanced equation to relate amounts of reactants and products, and determine the limiting reactant, theoretical yield and percent yield.10 min answer →
- How do we classify a reaction as precipitation, acid-base or oxidation-reduction, and what drives each?Topic 4.7 Types of Chemical Reactions: classify reactions as precipitation, acid-base, or oxidation-reduction, and identify the driving force of each.9 min answer →
Unit 5: Kinetics
Module overview →- How does a catalyst speed a reaction without being consumed, and what kinds of catalysis are there?Topic 5.11 Catalysis: explain how a catalyst increases the rate by providing an alternative pathway with a lower activation energy, and distinguish homogeneous, heterogeneous and enzyme catalysis.10 min answer →
- Why does temperature have such a large effect on reaction rate, and how does the collision model and the Arrhenius equation explain it?Topic 5.5 Collision Model: use collision theory and the Arrhenius equation to explain how activation energy, temperature, orientation and collision frequency control the rate constant.11 min answer →
- How does the concentration of a reactant change with time, and how can the shape of that change reveal the reaction order?Topic 5.3 Concentration Changes Over Time: use the integrated rate laws for zero-, first- and second-order reactions, identify order from a linear plot, and use the half-life of a first-order reaction.11 min answer →
- What is an elementary reaction, and why can its rate law be written directly from its molecularity?Topic 5.4 Elementary Reactions: identify the molecularity of an elementary step and write its rate law directly from its stoichiometry, distinguishing elementary steps from overall reactions.9 min answer →
- How does the rate of a reaction depend on the concentrations of the reactants, and how do we find that dependence?Topic 5.2 Introduction to Rate Law: write the rate law of a reaction, determine the reaction orders and the rate constant from initial-rate data, and interpret the meaning of order and the units of the rate constant.11 min answer →
- How is an overall reaction built from a sequence of elementary steps, and what is an intermediate?Topic 5.7 Introduction to Reaction Mechanisms: represent a reaction as a sequence of elementary steps, identify reaction intermediates and catalysts, and confirm that the steps sum to the overall equation.9 min answer →
- How does a potential-energy diagram for a multistep reaction show intermediates and identify the rate-determining step?Topic 5.10 Multistep Reaction Energy Profile: interpret an energy diagram with more than one peak to identify intermediates, the activation energy of each step, and the rate-determining step.9 min answer →
- How do we find the rate law when the slow step of a mechanism follows a fast equilibrium and contains an intermediate?Topic 5.9 Pre-Equilibrium Approximation: derive the rate law of a mechanism with a fast initial equilibrium followed by a slow step by expressing the intermediate concentration in terms of reactant concentrations.10 min answer →
- What does a reaction energy profile show about activation energy, the transition state and the enthalpy of reaction?Topic 5.6 Reaction Energy Profile: interpret a potential-energy diagram to identify the activation energy of the forward and reverse reactions, the transition state and the enthalpy of reaction.10 min answer →
- How does the rate-determining step of a mechanism set the rate law of the overall reaction?Topic 5.8 Reaction Mechanism and Rate Law: identify the rate-determining (slow) step of a mechanism and use it to write the rate law, and check a proposed mechanism against the experimental rate law.10 min answer →
- How do we define and measure the rate of a chemical reaction, and what controls how fast it goes?Topic 5.1 Reaction Rates: express the rate of a reaction in terms of the change in concentration of a reactant or product over time, relate rates through the stoichiometric coefficients, and identify the factors that influence rate.10 min answer →
Unit 6: Thermodynamics
Module overview →- How can the enthalpy of a reaction be estimated from the energies of the bonds broken and formed?Topic 6.7 Bond Enthalpies: estimate the enthalpy change of a reaction from average bond enthalpies, using the rule that breaking bonds absorbs energy and forming bonds releases it.10 min answer →
- What distinguishes an endothermic process from an exothermic one at the level of energy and bonds?Topic 6.1 Endothermic and Exothermic Processes: classify a process as endothermic or exothermic from the direction of energy flow, the sign of the enthalpy change and the bonds broken and formed.9 min answer →
- How does an energy diagram represent the relative potential energies of reactants and products and the enthalpy of a reaction?Topic 6.2 Energy Diagrams: draw and interpret an energy diagram showing the relative enthalpies of reactants and products and the enthalpy change of the reaction.9 min answer →
- Why does temperature stay constant during a phase change, and how is the energy of a phase change calculated?Topic 6.5 Energy of Phase Changes: explain why temperature is constant during a phase change, interpret a heating curve, and calculate the energy of a phase change from the enthalpy of fusion or vaporisation.10 min answer →
- What is a standard enthalpy of formation, and how is it used to calculate the enthalpy of a reaction?Topic 6.8 Enthalpy of Formation: use standard enthalpies of formation to calculate the enthalpy of a reaction as the sum for products minus the sum for reactants.10 min answer →
- How do we calculate the heat exchanged using specific heat capacity, and how does calorimetry measure it?Topic 6.4 Heat Capacity and Calorimetry: use the equation q equals mc delta T with specific heat capacity, and use calorimetry data to determine the heat of a process.11 min answer →
- How does heat flow between objects at different temperatures, and what does thermal equilibrium mean?Topic 6.3 Heat Transfer and Thermal Equilibrium: explain heat transfer as the flow of energy from a hotter object to a cooler one until thermal equilibrium is reached, relating it to the kinetic energy of particles.9 min answer →
- How does Hess's law let us combine known reactions to find the enthalpy of a reaction we cannot measure directly?Topic 6.9 Hess's Law: use Hess's law to determine the enthalpy of a reaction by combining the enthalpies of a series of reactions that add to the target, reversing and scaling as needed.11 min answer →
- What is the enthalpy of reaction, and how is it used in stoichiometric (thermochemical) calculations?Topic 6.6 Introduction to Enthalpy of Reaction: interpret the enthalpy of reaction as a state function and use thermochemical equations to relate the heat of a reaction to the amount of substance reacted.10 min answer →
Unit 7: Equilibrium
Module overview →- How do we calculate the equilibrium concentrations of all species from initial concentrations and the value of K?Topic 7.7 Calculating Equilibrium Concentrations: use an ICE table and the value of K to calculate equilibrium concentrations, including the use of the small-x (5%) approximation where valid.11 min answer →
- How do we calculate the value of an equilibrium constant from equilibrium concentrations or from initial data using an ICE table?Topic 7.4 Calculating the Equilibrium Constant: calculate the value of an equilibrium constant from equilibrium concentrations or pressures, using an ICE table where initial and equilibrium data are mixed.11 min answer →
- Why does the solubility of a salt decrease when a common ion is already present in solution?Topic 7.12 Common-Ion Effect: explain and calculate the reduced solubility of a salt in a solution that already contains one of its ions, using Le Chatelier's principle and Ksp.10 min answer →
- How do the relative rates of the forward and reverse reactions determine the direction a reversible reaction proceeds?Topic 7.2 Direction of Reversible Reactions: relate the direction of a reversible reaction to the relative magnitudes of the forward and reverse rates as the system approaches equilibrium.9 min answer →
- How does the free energy of dissolution relate to whether and how much a salt dissolves?Topic 7.14 Free Energy of Dissolution: relate the thermodynamic favourability of dissolving a salt to the enthalpy and entropy of dissolution and to the sign of the free energy change.10 min answer →
- What does it mean for a reaction to reach dynamic equilibrium, and what is happening at the particle level?Topic 7.1 Introduction to Equilibrium: describe dynamic equilibrium as the state in which the forward and reverse reaction rates are equal and concentrations are constant, at the particle level.9 min answer →
- How does a system at equilibrium respond to a change in concentration, pressure or temperature?Topic 7.9 Introduction to Le Chatelier's Principle: predict the direction a system at equilibrium shifts in response to a change in concentration, volume or pressure, or temperature, using Le Chatelier's principle.11 min answer →
- How does the solubility product constant describe the equilibrium of a slightly soluble salt, and how is it used?Topic 7.11 Introduction to Solubility Equilibria: write the solubility product expression Ksp for a slightly soluble salt and relate Ksp to molar solubility and ion concentrations.11 min answer →
- What does the magnitude of an equilibrium constant tell us about the extent of a reaction?Topic 7.5 Magnitude of the Equilibrium Constant: interpret the size of an equilibrium constant as a measure of the extent of reaction, relating large, small and intermediate K to the dominant species at equilibrium.9 min answer →
- Why does the solubility of certain salts depend on the pH of the solution?Topic 7.13 pH and Solubility: explain why the solubility of salts of weak acids or bases depends on pH, using Le Chatelier's principle applied to the dissolution and acid-base equilibria.10 min answer →
- How does the equilibrium constant change when a reaction is reversed, scaled or added to another reaction?Topic 7.6 Properties of the Equilibrium Constant: determine how K changes when a reaction is reversed (reciprocal), scaled (power) or combined with another reaction (product), and relate Kc to Kp.10 min answer →
- How are the reaction quotient and the equilibrium constant defined, and how do they predict the direction of reaction?Topic 7.3 Reaction Quotient and Equilibrium Constant: write the expression for the reaction quotient Q and the equilibrium constant K, and compare Q with K to predict the direction of reaction.11 min answer →
- How does comparing the reaction quotient with K explain the direction of a Le Chatelier shift?Topic 7.10 Reaction Quotient and Le Chatelier's Principle: explain the direction of an equilibrium shift quantitatively by comparing the reaction quotient Q with K after a disturbance.10 min answer →
- How can particulate diagrams and graphs represent a system at equilibrium and the relative amounts of species?Topic 7.8 Representations of Equilibrium: interpret and construct particulate diagrams and concentration-versus-time graphs that represent a system at equilibrium and the relative amounts of reactants and products.9 min answer →
Unit 8: Acids and Bases
Module overview →- What happens when acids and bases react, and how does a buffer resist changes in pH?Topic 8.4 Acid-Base Reactions and Buffers: predict the products of acid-base reactions, identify the salts formed, and explain how a buffer made from a weak acid and its conjugate base resists pH change.10 min answer →
- How does a titration curve reveal the equivalence point, the pH at key points, and the pKa of a weak acid?Topic 8.5 Acid-Base Titrations: interpret titration curves to find the equivalence point and pH at key points, and use the half-equivalence point to find pKa for a weak acid.11 min answer →
- What is the Bronsted-Lowry model of acids and bases, and how does it identify conjugate pairs?Topic 8.1 Introduction to Acids and Bases: identify Bronsted-Lowry acids, bases and conjugate acid-base pairs, and distinguish strong from weak acids and bases.9 min answer →
- How does molecular structure determine the relative strength of an acid?Topic 8.6 Molecular Structure of Acids and Bases: explain trends in acid strength in terms of bond strength, bond polarity, electronegativity and the stability of the conjugate base.10 min answer →
- How does the Henderson-Hasselbalch equation relate the pH of a buffer to the pKa and the ratio of conjugate base to acid?Topic 8.7 pH and pKa: use the Henderson-Hasselbalch equation to relate the pH of a buffer to the pKa and the ratio of conjugate base to weak acid, and explain buffer capacity.11 min answer →
- How are pH and pOH defined and calculated for strong acids and bases, and how do they relate through the water equilibrium?Topic 8.2 pH and pOH of Strong Acids and Bases: calculate pH and pOH from concentration for strong acids and bases, using the autoionisation of water and the relationship pH plus pOH equals 14 at 25 degrees Celsius.10 min answer →
- How do we calculate the pH and percent ionization of a weak acid or base using Ka or Kb?Topic 8.3 Weak Acid and Base Equilibria: use Ka or Kb with an ICE table to calculate the pH and percent ionization of a weak acid or base, and relate Ka, Kb and Kw.11 min answer →
Unit 9: Applications of Thermodynamics
Module overview →- How do we calculate the standard entropy change of a reaction from absolute entropies?Topic 9.2 Absolute Entropy and Entropy Change: use standard molar entropies to calculate the standard entropy change of a reaction as the sum for products minus the sum for reactants.9 min answer →
- How is the standard cell potential calculated, and how does it relate to the free energy change of a cell reaction?Topic 9.9 Cell Potential and Free Energy: calculate the standard cell potential from standard reduction potentials, and relate it to the free energy change with delta G standard equals minus n F E standard.11 min answer →
- How does the cell potential change when the concentrations are not standard, and what happens as a cell discharges?Topic 9.10 Cell Potential Under Nonstandard Conditions: predict how the cell potential changes with concentration using the Nernst relationship qualitatively, and explain why a cell potential falls to zero at equilibrium.10 min answer →
- How can a thermodynamically unfavorable reaction be driven by coupling it to a favorable one?Topic 9.7 Coupled Reactions: explain how an unfavorable reaction can be driven by coupling it to a favorable reaction so that the combined free energy change is negative.9 min answer →
- How do we calculate the amount of substance produced at an electrode from the current and time using Faraday's law?Topic 9.11 Electrolysis and Faraday's Law: use the current, time and the moles of electrons to calculate the mass or amount of substance produced at an electrode during electrolysis.11 min answer →
- How are the standard free energy change and the equilibrium constant related?Topic 9.5 Free Energy and Equilibrium: relate the standard free energy change to the equilibrium constant using delta G standard equals minus RT ln K, and use delta G equals delta G standard plus RT ln Q for non-standard conditions.11 min answer →
- How do enthalpy, entropy and free energy together explain the thermodynamics of dissolving a salt?Topic 9.6 Free Energy of Dissolution: analyze the dissolution of a salt using delta G equals delta H minus T delta S, and relate the sign of delta G to whether and how much the salt dissolves.10 min answer →
- How do galvanic and electrolytic cells use redox reactions to convert between chemical and electrical energy?Topic 9.8 Galvanic (Voltaic) and Electrolytic Cells: describe the structure and operation of galvanic and electrolytic cells, identifying the anode, cathode, electron flow and the direction of energy conversion.11 min answer →
- How does the Gibbs free energy combine enthalpy and entropy to determine whether a process is thermodynamically favorable?Topic 9.3 Gibbs Free Energy and Thermodynamic Favorability: use the equation delta G equals delta H minus T delta S to determine thermodynamic favourability and the temperature dependence of spontaneity.11 min answer →
- What is entropy, and how do we predict the sign of the entropy change for a process?Topic 9.1 Introduction to Entropy: describe entropy as a measure of the dispersal of energy and matter, and predict the sign of the entropy change for physical and chemical processes.9 min answer →
- Why can a thermodynamically favorable reaction still fail to proceed at a noticeable rate?Topic 9.4 Thermodynamic and Kinetic Control: distinguish thermodynamic favourability (sign of delta G) from kinetic feasibility (rate), and explain why a favorable reaction may be slow.9 min answer →