American Chemical Society·March (Local) · April (National)

USNCOUS National Chemistry Olympiad

From local school exam to IChO selection camp. Prepare with free simulators, practice tests, and coming-soon study materials — all in one place.

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Local Exam
60 MCQ · 110 min
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National Part I
60 MCQ · 110 min
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National Part II
Lab Practical · 90 min
✍️
National Part III
8 Free-Response · 90 min
📊 Data-Driven Strategy·3,262 real past-paper questions analyzed

The single biggest finding

Equilibrium jumps from just 3.3% of Local exam questions to 8.3% at the National Part I level — the exact same topic, tested far more heavily once you clear the Local round. Kinetics, Thermodynamics, and Electrochemistry are consistently the three largest categories at every level, together making up close to a third of every exam.

USNCO Local Exam

60 MCQ · roughly AP-Chemistry level · n = 1,500 questions

Thermodynamics
10.3%
Electrochemistry
9.7%
Kinetics
9.7%
Bonding
9.7%
Atomic Structure
8.1%
Organic Chemistry
7.7%
States of Matter
6.5%
Other
38.3%

USNCO National Part I

60 MCQ · notably deeper than Local · n = 1,560 questions

Kinetics
10%
Thermodynamics
9.2%
Electrochemistry
8.9%
Organic Chemistry
8.8%
Bonding
8.5%
Descriptive Chemistry
8.5%
Equilibrium
8.3%
Other
37.8%

USNCO National Part II

Free-response · 6 questions · n = 156 questions

Kinetics
11.5%
Thermodynamics
10.3%
Descriptive Chemistry
10.3%
Electrochemistry
9.6%
Equilibrium / Solubility
3.2%
Acid-Base Equilibrium / Titration
2.6%
Acid-Base Equilibrium / Buffers
1.9%
Other
50.6%

USNCO National Part III

Lab practical · 2 tasks · n = 46 questions

Qualitative Analysis
13%
Acid-Base Titration
8.7%
Kinetics
6.5%
Electrochemistry
4.3%
Calorimetry
4.3%
Chromatography
4.3%
Paper Chromatography
2.2%
Other
56.5%
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Part III is a different game entirely
Qualitative Analysis and Acid-Base Titration dominate the lab practical — real wet-chemistry skills, not the conceptual recall that carries you through Local and Part I. See our Advanced Chemistry ebook for the analytical-chemistry chapter built specifically for this gap.
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Organic chemistry is bigger than you'd expect
7–9% of both Local and Part I MCQs are organic chemistry — on par with atomic structure. Don't leave it for last; our Organic Chemistry hub covers this at a depth that comfortably exceeds what's tested here.

Ready to prepare?

USNCO goes deeper than AP Chemistry

Expect harder thermodynamics, coordination chemistry (crystal field theory), multi-step organic synthesis, and advanced stereochemistry on the National exam. Use the simulations to build the conceptual depth these topics demand — not just AP-level recall.

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