All units

The units below follow a recommended order that builds from atomic structure toward reactions and calculations. You can work through them in sequence, or open any unit directly if you already know what you want to practice.

14 units available with 1415 practice questions.

What the labels mean

Content level: CoreExpected foundation for a general high school chemistry audience.
Content level: ChallengeEnrichment or more demanding reasoning within high school chemistry.

Content level is separate from question difficulty.

Unit 01Content level: Core
Stoichiometry
The math of chemical reactions: moles, mass, balanced equations, limiting reagents, and yield.
Balancing Chemical EquationsEmpirical formulaLab: Hydrate Analysis & Gravimetric Thermal DecompositionLimiting reagentsDefinition of the mole/Mole conversions
Questions
149
Topics
8
Levels
Easy · Medium · Hard
Example question · Easy
Why must a porcelain crucible be heated strongly and cooled in a desiccator before adding a hydrated salt sample in a gravimetric hydrate analysis lab?
View unit: View Stoichiometry unit
Unit 02Content level: Core
Periodic Trends
Patterns across the periodic table, how atomic structure explains size, ionization energy, and shielding.
Electronegativity ionization energy atomic radiusShielding/Electron Orbital structure
Questions
65
Topics
2
Levels
Easy · Medium · Hard
Example question · Easy
Which of the following elements has the largest atomic radius: Sodium (Na), Magnesium (Mg), or Potassium (K)?
View unit: View Periodic Trends unit
Unit 03Content level: Core
Types of Solids and IMFS
Practice questions and topics from Types of Solids and IMFS.
Types of elementsIntro to IMFSJustification with IMFSLab: Paper & Thin-Layer Chromatography of DyesSolids
Questions
106
Topics
5
Levels
Easy · Medium · Hard
Example question · Easy
Which of the following elements is classified as a semiconductor metalloid?
View unit: View Types of Solids and IMFS unit
Unit 04Content level: Core
Molecular Structure
Lewis structures, the octet rule, and formal charge for building and evaluating molecules.
Formal ChargeLewis structuresOctet rule
Questions
66
Topics
3
Levels
Easy · Medium · Hard
Example question · Easy
What is the total number of valence electrons in the Lewis structure of the ammonium cation, NH₄⁺?
View unit: View Molecular Structure unit
Unit 05Content level: Core
Bonding
How atoms connect: VSEPR shapes, hybridization, electron orbitals, and sigma vs. pi bonds.
HybridizationElectron orbitalsSigma and Pi bondsVSEPR
Questions
87
Topics
4
Levels
Easy · Medium · Hard
Example question · Easy
What is the molecular geometry of carbon tetrachloride (CCl₄)?
View unit: View Bonding unit
Unit 06Content level: Core
Gases, Solutions & Spectroscopy
Practice questions and topics from Gases, Solutions & Spectroscopy.
Non-AP Extension: Graham's Law of Effusion & van der Waals EquationBeer's Law SpectroscopySpectroscopy & Beer-Lambert LawIdeal Gas Law, Dalton's Law & Gas StoichiometryKinetic Molecular Theory & Speed Distributions
Questions
108
Topics
6
Levels
Easy · Medium · Hard
Example question · Easy
According to the Beer-Lambert Law (A = ε · b · c), what is the relationship between absorbance (A) and path length (b) of the sample cuvette?
View unit: View Gases, Solutions & Spectroscopy unit
Unit 07Content level: Core
Chemical Reactions
Practice questions and topics from Chemical Reactions.
Acid-Base Neutralization & Proton TransferLab: Gravimetric Analysis of PrecipitationLab: Oxidation-Reduction Titration (KMnO4)Net Ionic Equations & Precipitation ReactionsOxidation Numbers & Identifying Redox Reactions
Questions
134
Topics
7
Levels
Easy · Medium · Hard
Example question · Easy
In a gravimetric analysis to determine the sulfate content of an unknown fertilizer, which soluble reagent is added in excess to precipitate all sulfate quantitatively as an insoluble solid?
View unit: View Chemical Reactions unit
Unit 08Content level: Core
Chemical Kinetics
Practice questions and topics from Chemical Kinetics.
Collision Theory & Arrhenius EquationIntegrated Rate Laws & Half-LifeElementary Steps & Reaction MechanismsReaction Rates & Differential Rate Laws
Questions
112
Topics
4
Levels
Easy · Medium · Hard
Example question · Easy
If a reaction rate is independent of the concentration of reactant A, what is the order with respect to A?
View unit: View Chemical Kinetics unit
Unit 09Content level: Core
Thermochemistry & Thermodynamics
Practice questions and topics from Thermochemistry & Thermodynamics.
Bond Dissociation Energies & Enthalpy of ReactionHeat Transfer, Specific Heat & CalorimetryEntropy, Gibbs Free Energy & Thermodynamic FavorabilityHess's Law & Standard Enthalpies of FormationLab: Coffee-Cup Calorimetry & Heat of Reaction
Questions
122
Topics
5
Levels
Easy · Medium · Hard
Example question · Easy
What is the heat absorbed by 200.0 g of water (c = 4.184 J/g°C) when heated by 10.0°C?
View unit: View Thermochemistry & Thermodynamics unit
Unit 10Content level: Core
Chemical Equilibrium & Solubility
Practice questions and topics from Chemical Equilibrium & Solubility.
Equilibrium Constant & Reaction Quotient Q vs KICE Tables & Equilibrium CalculationsSolubility Product Ksp & Common Ion EffectLab: Spectrophotometric Equilibrium Constant DeterminationLe Chatelier's Principle & System Shifts
Questions
122
Topics
5
Levels
Easy · Medium · Hard
Example question · Easy
In the lab determining the equilibrium constant for Fe³⁺(aq) + SCN⁻(aq) ⇌ [Fe(SCN)]²⁺(aq), what visible property is used to quantify the equilibrium concentration of the product?
View unit: View Chemical Equilibrium & Solubility unit
Unit 11Content level: Core
Acids, Bases & Aqueous Equilibria
Practice questions and topics from Acids, Bases & Aqueous Equilibria.
Buffer Solutions & Henderson-Hasselbalch EquationpH, pOH, Kw & Strong Acid-Base CalculationsAcid-Base Titration Curves & Chemical IndicatorsWeak Acids, Weak Bases, Ka/Kb & Salt Hydrolysis
Questions
112
Topics
4
Levels
Easy · Medium · Hard
Example question · Easy
What is the pH of a 0.0010 M HCl solution at 25°C?
View unit: View Acids, Bases & Aqueous Equilibria unit
Unit 12Content level: Core
Electrochemistry & Applications of Thermodynamics
Practice questions and topics from Electrochemistry & Applications of Thermodynamics.
Electrolytic Cells & Faraday's Law CalculationsCell Potential, Gibbs Free Energy & Equilibrium ConstantGalvanic Cells & Standard Reduction PotentialsNernst Equation & Concentration Cells
Questions
112
Topics
4
Levels
Easy · Medium · Hard
Example question · Easy
In an electrochemical cell, which process occurs at the ANODE?
View unit: View Electrochemistry & Applications of Thermodynamics unit
Unit 13Content level: Challenge
Organic Chemistry
Practice questions and topics from Organic Chemistry.
Functional Groups & Organic FamiliesHydrocarbons & IUPAC NomenclatureStructural Isomerism & StereochemistryOrganic Reactions: Substitution, Addition & Combustion
Questions
60
Topics
4
Levels
Easy · Medium
Example question · Easy
What is the general molecular formula for an acyclic (open-chain) alkane containing n carbon atoms?
View unit: View Organic Chemistry unit
Unit 14Content level: Challenge
Nuclear Chemistry
Practice questions and topics from Nuclear Chemistry.
Mass Defect, Binding Energy & E = mc²Fission, Fusion & Nuclear EnergyHalf-Life & Radioactive Decay KineticsNuclear Decay & Balancing Nuclear Equations
Questions
60
Topics
4
Levels
Easy · Medium · Hard
Example question · Easy
An alpha particle is identical to a:
View unit: View Nuclear Chemistry unit