American Chemical Society·March (Local) · April (National)
USNCOUS National Chemistry Olympiad
The pathway from local school exam to IChO selection camp. USNCO tests deeper than AP Chemistry — expect harder thermodynamics, coordination chemistry, and multi-step organic synthesis on the national exam.
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Local Exam
60 MCQ · 110 min
Held at participating schools in March. Top scorers qualify for the National Exam.
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National Part I
60 MCQ · 110 min
Taken by ~1000 top local scorers. Covers general, organic, analytical, and physical chemistry.
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National Part II
Lab Practical · 3 tasks · 90 min
Hands-on laboratory skills. Only at the Study Camp.
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National Part III
8 Free-Response · 90 min
Extended problem-solving. Top ~20 scorers become IChO team candidates.
Simulators by USNCO Topic Area
Click any tool to open it — all free, no account needed
General Chemistry
Heavily tested — both local and national
Atomic & Molecular Structure
Core MCQ topic
Electrochemistry
National exam focus
Organic Chemistry
National Part I & III
Coordination & Advanced Inorganic
National Part III & IChO camp
Question Bank & Past Papers
Coming Soon📋Local Exam MCQ Bank
Full 60-question timed sets from USNCO Local exams 2000–2025 with answer explanations
Q3 2025 📄National Exam Archive
National Part I, II, and III past papers with worked solutions (2000–2025)
Q3 2025 ⏱️Timed Practice Mode
60-question mock local exam with 110-minute countdown and score report
Q4 2025 🔬Lab Practical Guide
Interactive walkthrough of common Part II lab techniques and calculations
2026 Build the Depth USNCO Demands
Start with any simulator — free, no account required.