If your student loves chemistry and wants a serious academic challenge, the US National Chemistry Olympiad (USNCO) is one of the most respected proving grounds in the country.
Administered by the American Chemical Society (ACS) since 1984, the USNCO is a multi-tier competition that ultimately selects four students to represent the United States at the International Chemistry Olympiad (IChO). Understanding the USNCO syllabus, the exam format, and the eligibility rules is the first step toward a focused preparation plan. Below we break down how the competition works and what topics you need to master.
How the USNCO Is Structured
The USNCO runs through ACS Local Sections, which are geographic chapters spread across the country. Students advance through three distinct stages:
- Local Exam: Open to high school students nationwide, this is typically a multiple-choice exam administered through your regional ACS Local Section. Top performers are nominated by their USNCO coordinators to advance.
- National Exam: Nominated students sit a rigorous three-part exam (more on its format below).
- Study Camp: The top scorers nationwide (historically around 20 students) are invited to an intensive multi-week study camp, where the four-member IChO team and alternates are selected.
Exact dates, score cutoffs, registration steps, and any fees change year to year and vary by Local Section. Always confirm current details on the official ACS Olympiad pages and with your local coordinator.
The National Exam Format
The National Exam is where the USNCO syllabus is truly tested. It is built from three parts that reward both speed and depth:
- Part I — Multiple choice: Around 60 questions spanning the full breadth of the syllabus, completed under time pressure.
- Part II — Free response: A set of written problems requiring complete explanations, derivations, and calculations, with partial credit available.
- Part III — Lab practical: Hands-on experimental tasks such as titration, qualitative analysis, and chromatography, testing real bench skills rather than theory alone.
This combination is what makes the Olympiad harder than a typical classroom test: it is not enough to recognize the right answer, you must produce it cleanly and execute in the lab.
What the USNCO Syllabus Covers
The content sits roughly at the level of AP Chemistry, with added depth in introductory organic and physical chemistry. Expect the exam to draw from the following core areas:
Physical and general chemistry
- Stoichiometry and the mole concept
- States of matter: gases, liquids, and solids
- Thermodynamics and thermochemistry
- Chemical kinetics and reaction rates
- Equilibrium, including acids and bases
- Electrochemistry
Structure and reactivity
- Electronic structure and periodicity
- Chemical bonding and molecular geometry
- Descriptive and coordination chemistry
- Introductory organic chemistry
- Laboratory technique and data analysis
Because the Olympiad emphasizes less-standard topics like organic and coordination chemistry more heavily than a standard AP course, strong students often need supplemental study beyond their school curriculum.
Who Is Eligible
The headline rules are straightforward, though you should verify the current version each season:
- Open to students in grades 9-12 who will not graduate before May of the competition year, and who are under 20 years old as of the relevant July date.
- To advance to the National Exam, students must be US citizens or legal permanent residents. Others may still take the Local Exam.
- Generally no more than two students per high school per Local Section may be nominated for the National Exam.
- Prior IChO gold medalists are not eligible to compete again.
How to Prepare Strategically
The most effective preparation pairs deep content review with timed problem-solving and real lab practice. Working past exams, mastering free-response structure, and rehearsing practical techniques all matter. Many ambitious students also build a broader STEM profile across multiple academic competitions, which strengthens the analytical and research skills that chemistry rewards. Pursuing independent research projects can deepen conceptual understanding and reinforce lab fluency that pays off on Part III.
At BIAA, we help K-12 students plan rigorous, honest pathways into elite STEM contests. Explore our research mentorship program or visit the BIAA homepage to find the right starting point for your chemistry journey.