This page features training materials and preparation tips for the International Chemistry Competition.

General Information

Our team frequently receives the questions "How should I prepare for the competition?" and "What books would you recommend?". Diverse skills are required to approach the IChC problems, including the following key skills that you will train throughout the competition:

• Creativity and problem-solving skills (e.g., logical reasoning, synthesis planning).
• Knowledge about chemistry (e.g., reaction mechanisms, molecular structures, periodic trends).
• Science reading comprehension (i.e., Semi-Final Round).
• Analytical thinking (e.g., identifying reaction pathways, interpreting spectra).
• Ability to apply theoretical knowledge (e.g., using thermodynamic principles, balancing equations).
• Time management skills (i.e., Semi-Final & Final Round).
• Adaptability to different formats (e.g., multiple-choice, calculations, or structure drawing).

There are multiple problems and questions in each round (Qualification, Semi-Final, and Final Round) from a variety of chemistry subjects. Below, we provide detailed information about the core chemistry fields covered in IChC, along with key concepts and equations that are fundamental to each area:

• General Chemistry & Atomic Structure:
  General chemistry establishes the foundational principles that govern all chemical phenomena. This includes understanding atomic structure, electron configurations, periodic trends, and the nature of chemical bonding. Mastery of these concepts is essential for predicting chemical behavior and understanding more advanced topics.
  • Electron Configuration: Aufbau principle, Hund's rule, and Pauli exclusion principle
  • Periodic Trends: Electronegativity, ionization energy, atomic radius, electron affinity
  • Quantum Numbers: \(n, l, m_l, m_s\) (Principal, angular momentum, magnetic, spin)
  • de Broglie Wavelength: \(\lambda = \frac{h}{mv}\) (Wave nature of electrons)
  • Bohr Model Energy: \(E_n = -\frac{13.6 \text{ eV}}{n^2}\) (Hydrogen atom energy levels)


• Chemical Bonding & Molecular Structure:
  Understanding how atoms connect to form molecules is central to chemistry. This includes ionic, covalent, and metallic bonding, as well as intermolecular forces. Molecular geometry, hybridization, and molecular orbital theory help predict and explain molecular properties and reactivity.
  • VSEPR Theory: Predicting molecular geometry from electron pair repulsion
  • Hybridization: sp, sp², sp³, sp³d, sp³d² orbital mixing
  • Bond Order: \(\text{Bond Order} = \frac{\text{bonding electrons} - \text{antibonding electrons}}{2}\)
  • Dipole Moment: \(\mu = q \times d\) (Charge separation in polar molecules)
  • Lattice Energy: \(U \propto \frac{z^+ z^-}{r_+ + r_-}\) (Born-Landé equation approximation)


• Chemical Thermodynamics:
  Thermodynamics in chemistry deals with energy changes in chemical reactions and phase transitions. Understanding enthalpy, entropy, and Gibbs free energy allows prediction of reaction spontaneity and equilibrium positions. These concepts are fundamental to understanding why reactions occur and how to control them.
  • Gibbs Free Energy: \(\Delta G = \Delta H - T\Delta S\) (Spontaneity criterion)
  • Enthalpy of Reaction: \(\Delta H_{rxn} = \sum \Delta H_f(\text{products}) - \sum \Delta H_f(\text{reactants})\) (Hess's Law)
  • Standard Free Energy: \(\Delta G° = -RT\ln K\) (Relationship to equilibrium constant)
  • Clausius-Clapeyron: \(\ln\frac{P_2}{P_1} = \frac{\Delta H_{vap}}{R}\left(\frac{1}{T_1} - \frac{1}{T_2}\right)\) (Vapor pressure vs. temperature)
  • Heat Capacity: \(q = nC\Delta T\) (Heat absorbed at constant pressure or volume)


• Chemical Kinetics:
  Kinetics is the study of reaction rates and the factors that influence them. Understanding rate laws, reaction mechanisms, and activation energy helps explain how reactions proceed and how to control their speed. This field is essential for industrial chemistry, biochemistry, and environmental science.
  • Rate Law: \(\text{Rate} = k[A]^m[B]^n\) (Dependence on concentrations)
  • Arrhenius Equation: \(k = Ae^{-E_a/RT}\) (Temperature dependence of rate constant)
  • Half-Life (1st order): \(t_{1/2} = \frac{\ln 2}{k} = \frac{0.693}{k}\)
  • Integrated Rate Laws: \([A]_t = [A]_0 e^{-kt}\) (First-order); \(\frac{1}{[A]_t} = \frac{1}{[A]_0} + kt\) (Second-order)
  • Catalysis: Lowering activation energy without being consumed in the reaction


• Chemical Equilibrium:
  Equilibrium describes the state where forward and reverse reactions occur at equal rates. Understanding equilibrium constants, Le Chatelier's principle, and how to manipulate equilibrium positions is crucial for predicting reaction outcomes and optimizing chemical processes.
  • Equilibrium Constant: \(K = \frac{[C]^c[D]^d}{[A]^a[B]^b}\) (For aA + bB ⇌ cC + dD)
  • Reaction Quotient: \(Q\) compared to \(K\) predicts reaction direction
  • Le Chatelier's Principle: Systems shift to counteract applied stress
  • Relationship between K values: \(K_p = K_c(RT)^{\Delta n}\) (For gaseous equilibria)
  • Solubility Product: \(K_{sp} = [M^+]^m[X^-]^n\) (For sparingly soluble salts)


• Acids, Bases & Electrochemistry:
  Acid-base chemistry and electrochemistry are interconnected fields dealing with proton and electron transfer. Understanding pH, buffer systems, and electrochemical cells is essential for applications ranging from biological systems to batteries and corrosion prevention.
  • pH Definition: \(\text{pH} = -\log[H^+]\); \(\text{pOH} = -\log[OH^-]\); \(\text{pH} + \text{pOH} = 14\) (at 25°C)
  • Henderson-Hasselbalch: \(\text{pH} = \text{p}K_a + \log\frac{[A^-]}{[HA]}\) (Buffer equation)
  • Nernst Equation: \(E = E° - \frac{RT}{nF}\ln Q\) (Cell potential under non-standard conditions)
  • Faraday's Laws: \(m = \frac{MIt}{nF}\) (Mass deposited in electrolysis)
  • Cell Potential: \(E°_{cell} = E°_{cathode} - E°_{anode}\) (Standard reduction potentials)


• Organic Chemistry:
  Organic chemistry focuses on carbon-containing compounds, their structures, properties, and reactions. Understanding functional groups, reaction mechanisms (substitution, elimination, addition), and stereochemistry is vital for fields from pharmaceuticals to materials science.
  • Functional Groups: Alcohols, aldehydes, ketones, carboxylic acids, amines, esters, ethers, etc.
  • Reaction Mechanisms: SN1, SN2, E1, E2, electrophilic addition, nucleophilic addition
  • Stereochemistry: Chirality, R/S configuration, E/Z isomerism, optical activity
  • Aromaticity: Hückel's rule (\(4n+2\) π electrons), electrophilic aromatic substitution
  • Spectroscopy Interpretation: IR, NMR, Mass Spectrometry for structure determination


• Inorganic & Coordination Chemistry:
  Inorganic chemistry covers the properties and reactions of all elements, with special emphasis on transition metals and their coordination compounds. Crystal field theory, ligand field theory, and understanding of coordination geometries are essential for explaining color, magnetism, and reactivity.
  • Crystal Field Splitting: \(\Delta_o\) (octahedral) and \(\Delta_t\) (tetrahedral) energy differences
  • Spectrochemical Series: I⁻ < Br⁻ < Cl⁻ < F⁻ < OH⁻ < H₂O < NH₃ < en < NO₂⁻ < CN⁻ < CO
  • Magnetic Properties: \(\mu = \sqrt{n(n+2)}\) BM (Spin-only formula for magnetic moment)
  • HSAB Theory: Hard-soft acid-base concept for predicting complex stability
  • Coordination Number: Common geometries (linear, tetrahedral, square planar, octahedral)

Additionally, the Semi-Final Round usually includes research problems, which require you to read a scientific article. The Final Round can also include questions related to the previous problems (e.g., the scientific article) from the Semi-Final Round and Qualification Round. Consider checking out this page to understand better how IChC differs from other competition formats and what to expect:

• About IChC (How IChC differs from other competitions and what to expect.)

Preparation Tips for Participants

Below, you will find a set of tips designed to help you prepare for the International Chemistry Competition. These recommendations are tailored to support your success in the competition and enhance your skills:

1. Know the Competition Format
   Start by understanding the structure and requirements of each round: the Qualification Round focuses on diverse topics across all branches of chemistry, the Semi-Final Round includes reading comprehension tasks based on scientific literature, and the Final Round tests quick problem-solving under time pressure. Reviewing past IChC problems will help you grasp the diversity and difficulty level of each round.


2. Focus on the Core Topics
   The problems in IChC come from a range of chemistry areas, including general chemistry, chemical bonding, thermodynamics, kinetics, equilibrium, acid-base chemistry, electrochemistry, organic chemistry, and inorganic chemistry. Make sure you are comfortable with the fundamental concepts, reaction mechanisms, and key equations in these topics to build a solid foundation for tackling problems.


3. Train Your Problem-Solving Skills
   Work on improving your creativity, reasoning, and analytical thinking by solving chemistry problems from textbooks, past olympiads, and the resources recommended below. Practice balancing equations, drawing mechanisms, interpreting spectra, and performing stoichiometric calculations. These skills will help you approach even the most challenging IChC problems effectively.


4. Learn from Mistakes
   Reflecting on your mistakes and learning from them is an essential part of growth in any competition. First, try to solve the problems as far as possible. Then, compare them to a given solution and evaluate at which steps you made mistakes and correct them accordingly.


5. Use the Available Resources
   Take advantage of past IChC problem sets, recommended textbooks, and online platforms to sharpen your skills. Additionally, the IChC team is available to provide assistance and guidance; do not hesitate to contact us for support.


6. Prepare for Scientific Reading (Semi-Final Round)
   The Semi-Final Round often features problems inspired by scientific articles from chemistry journals. Practice reading and summarizing scientific texts, focusing on extracting relevant experimental data, understanding reaction schemes, and connecting findings to broader chemical concepts. Reading papers from journals like JACS, Angewandte Chemie, or Chemical Reviews will help develop this skill.


7. Simulate Timed Problem-Solving (Final Round)
   Time management is essential for the Semi-Final and even more the Final Round. Practice solving problems within set time limits to develop a sense of pacing.


8. Collaborate and Learn from Others
   Join study groups, chemistry clubs, or connect with IChC Ambassadors to discuss strategies and share insights. Collaboration can help you explore new problem-solving approaches and stay motivated throughout your preparation.


9. Enjoy the Learning Experience
   Keep in mind that IChC prioritizes learning and expanding your knowledge while participating. Engage with each problem, and treat every challenge as an opportunity to deepen your understanding of the molecular world and the principles that govern chemical transformations.

Book Recommendations

Most introductory school and university chemistry textbooks are useful and contain the information required to approach the problems. For reference, please have a look at the following list of recommended books:

• General Chemistry:
• Peter Atkins and Julio de Paula. Atkins' Physical Chemistry. Oxford University Press.
• Raymond Chang and Kenneth Goldsby. Chemistry, 13th Edition. McGraw-Hill.
• Theodore Brown, H. Eugene LeMay, Bruce Bursten, et al. Chemistry: The Central Science. Pearson.
• Steven Zumdahl and Susan Zumdahl. Chemistry, 10th Edition. Cengage Learning.


• Organic Chemistry:
• Jonathan Clayden, Nick Greeves, and Stuart Warren. Organic Chemistry, 2nd Edition. Oxford University Press.
• Paula Yurkanis Bruice. Organic Chemistry, 8th Edition. Pearson.
• John McMurry. Organic Chemistry, 9th Edition. Cengage Learning.
• Francis Carey and Robert Sundberg. Advanced Organic Chemistry (Parts A and B). Springer.
• K. Peter C. Vollhardt and Neil E. Schore. Organic Chemistry: Structure and Function. W.H. Freeman.


• Inorganic Chemistry:
• Gary Miessler, Paul Fischer, and Donald Tarr. Inorganic Chemistry, 5th Edition. Pearson.
• Catherine Housecroft and Alan Sharpe. Inorganic Chemistry, 5th Edition. Pearson.
• James Huheey, Ellen Keiter, and Richard Keiter. Inorganic Chemistry: Principles of Structure and Reactivity. Pearson.
• Duward Shriver and Peter Atkins. Inorganic Chemistry, 5th Edition. W.H. Freeman.


• Physical Chemistry:
• Peter Atkins and Julio de Paula. Physical Chemistry: Thermodynamics, Structure, and Change. W.H. Freeman.
• Ira Levine. Physical Chemistry, 6th Edition. McGraw-Hill.
• Donald McQuarrie and John Simon. Physical Chemistry: A Molecular Approach. University Science Books.
• Keith Laidler. Chemical Kinetics, 3rd Edition. Pearson.


• Analytical Chemistry:
• Daniel Harris. Quantitative Chemical Analysis, 10th Edition. W.H. Freeman.
• Douglas Skoog, Donald West, F. James Holler, and Stanley Crouch. Fundamentals of Analytical Chemistry. Cengage Learning.
• Robert Silverstein, Francis Webster, and David Kiemle. Spectrometric Identification of Organic Compounds. Wiley.