The Ti-36X calculator meets the criteria for all levels of Chemistry Olympiads and has the most functionality of other calculators. It also has built-in constants and better buttons than comparable Texas Instruments calculators.
Note that the Ti-84 or any other graphing calculator is prohibited in Chemistry Olympiads.
The 2020 USNCO National Exam Part I cutoff score was 40. This was the only year where the American Chemistry Society has explicitly revealed its cutoff, mainly due to the ongoing coronavirus pandemic.
Instead of aiming for the cutoff score, just try your best.
Atkins' Chemical Principles: The Quest For Insight is a textbook commonly mentioned in the Chemistry Olympiad community, as it is a well-written textbook that introduces all of the necessary fundamentals. The theoretical knowledge from Chemical Principles is enough for 90% of Chemistry Olympiads. The remaining 10% that isn't covered is primarily organic chemistry, inorganic reactions, and common advanced topics (MCB, CFT, spectroscopy, Slater's Rules, etc.)
Over the last ten years, private tutoring has become popular within the Chemistry Olympiad scene. While tutoring can be effective, we also encourage you to try preparing for the exam alone.
Here are some things to consider:
The scope of the US National test for both the Locals Exam and the Nationals Part I Exam is as follows. Any test before 2012 does not follow this format, and therefore not recommended to use them as practice material.
Stoichiometry/Solutions (6 questions): Knowledge of your first-year high school general chemistry.
Descriptive Chemistry (3~5 questions): Flame tests, ion colors, selective precipitation, and trivial chemistry.
Laboratory (1~3 questions): Human errors, procedures, and lab equipment knowledge.
States of Matter (6 questions): Three types of matter, phase changes, phase diagrams, IMFs, vapor pressure.
Thermodynamics (6 questions): Thermocycles, enthalpy, entropy, and Gibbs free energy. Although most questions are calculations, there have always been at least one theoretical question.
Kinetics (6 questions): Half-life, elementary reactions (including pre-equilibrium and SSA), integrated rate laws, energy diagrams, and reaction rates.
Equilibrium (6 questions): Chemical equilibrium (including solubility and acid-base chemistry).
Redox/Electrochemistry (6 questions): Redox reactions and electrochemistry.
Atoms (6 questions): Atomic theory and periodicity.
Molecules (6 questions): Bonding and molecular structure.
Organic Chemistry (5 questions): All of the questions can be answered with Kleins' Organic Chemistry.
Biochemistry (1 questions): There is always one biochemistry question, but it's probably not worth your time to study it.
The Part II Exam contains topics similar to Part I, but the concepts are often combined. Biochemistry and Laboratory topics are never included in Part II.
Textbook problems, such as those in Atkins' Chemical Principles tend to be very limited and straightforward and going through large banks of them can lead you to practice steps as opposed to strategy. Many Olympiads utilize 'trick' questions that are similar to common textbook questions but can not be solved correctly from the practiced straightfoward methods.
Additionally, its often beneficial to practice a bit higher than your comfort level. This doesn't mean you should jump from simple textbook problems to IChO problems, but you shouldn't be afraid of trying past Olympiad exams. Start practicing as soon as you've absorbed the fundamentals.
While it may be helpful to dive deeper on a particular interest, no textbook that is introduced here should be read primarily for the purpose of preparing for regular Olympiad exams with the exception of organic chemistry.
Inorganic ChemistryMiessler's Inorganic Chemistry is compact, concise, and overall provides a decent introduction to the field, although some of its explanations can sometimes be rather confusing and difficult to understand.
Housecroft's Inorganic Chemistry is long, detailed, and very dense. Most of its explanations are simple, but it contains a lot of specific knowledge that isn't required for Olympiads.
Klein's Organic Chemistry is well explained, simple, introductory, and focused on mechanisms. This is the only organic chemistry textbook that is truly required for Chemistry Olympiads, but might not be sufficient for competitions harder or equivalent to IChO.
Clayden's Organic Chemistry is also well explained, but more detailed, organized, and retains the focus on mechanisms. This is one of the best books in the field of Organic Chemistry but not necessary for Chemistry Olympiads.
Atkins' Elements of Physical Chemistry is a well explained, decent introduction to physical chemistry, and doesn't go into too advanced mathematics. If you are truly interested in this field, you should check out this book.
Analytical ChemistryHarris' Quantiative Chemical Analysis is a great read with practice for advanced calculations and very good practice problems.
BiochemistryLehninger Principles of Biochemistry is a well-written biochemistry textbook, although not relevant to Olympiad exams.