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Chemistry Olympiad Exams

Digital Local Section and National Exam Course Preview

If you are a student, parent, guardian, or teacher who would like a preview of how the 2021 USNCO digital Local Section Exam (hosted nationally, contact your coordinator to see if you will use this system) and National Exam Part 1 will be hosted in the ACS Learning Center, please follow this link for a short video walkthrough. Your local section/international chapter coordinator will provide you specific details of how students in your area will participate this year. If you have any additional questions, please contact

New Initiative - Annotated Exam Solutions

Volunteers are coordinating efforts to annotate past USNCO exams to further help students prepare. This project is covering the Local Section Exam and Part 1 of the National Exam (detailed solutions are provided directly in the files for National Exam Parts 2 and 3).

This project is being coordinated by Dr. Qiang "Steven" Chen.  If you would like to assist in annotating exams, please contact

To suggest corrections to past solutions, please submit them in the USNCO Preparation Hub.

Exam Organization

Multiple choice USNCO (both local and national) exams cover the following topics:

 1 – 6  Stoichiometry/Solutions
 7 – 12  Descriptive/Laboratory
 13 – 18  States of Matter
 19 – 24  Thermodynamics
 25 – 30  Kinetics
 31 – 36  Equilibrium
 37 – 42  Oxidation - Reduction
 43 – 48  Atomic Structure/Periodicity
 49 – 54  Bonding/Molecular Structure
 55 – 60  Organic/Biochemistry

Local Chemistry Olympiad Exams

Nearly 16,000 U.S. students participate in Local Chemistry Olympiad competitions. Over 70% of Local Sections use the Local Section Exam prepared by the ACS Chemistry Olympiad Examination Task Force. Exams are administered annually in March and students are nominated for the U.S. National Chemistry Olympiad competition based on their performance.

National Chemistry Olympiad Exams

The U.S. National Chemistry Olympiad National Exam is a 3-part, 4 hour and 45 minute exam administered in mid or late April by ACS Local Sections and International Chapters. More than 1000 students participate in this exam each year.

Part I Part II Part III
  • Multiple Choice
  • 90-minutes
  • 60 multiple choice questions
  • Covers broad chemistry topics
  • Problem Solving
  • 105 minutes
  • 8 written questions
  • Covers chemical theories and models
  • Lab Practical
  • 90 minutes
  • 2 laboratory practicals
  • Involves problem solving in the laboratory


Exams Task Force Members

  • Chair: Seth N. Brown, University of Notre Dame, Notre Dame, IN
  • James Ayers, Colorado Mesa University, Grand Junction, CO
  • Jerry Bell, Simmons University, Boston, MA (retired)
  • Mark DeCamp, University of Michigan, Dearborn, MI (retired)
  • Joshua de Groot, College of Southern Idaho, Twin Falls, ID
  • James Dohm, Vanderbilt University, Nashville, TN
  • Xu Duan, Holton-Arms School, Bethesda, MD
  • Valerie Ferguson, Moore HS, Moore, OK
  • Julie Furstenau, Thomas B. Doherty HS, Colorado Springs, CO (retired)
  • Kimberly Gardner, United States Air Force Academy, CO
  • Paul Groves, South Pasadena HS, South Pasadena, CA
  • Nicolas Hamel, Clackamas Community College, Oregon City, OR
  • David W. Hostage, Taft School, Watertown, CT
  • John Kotz, State University of New York, Oneonta, NY (retired)
  • Michael A. Morgan, Francisco Bravo Medical Magnet HS, Los Angeles, CA
  • Jane Nagurney, Scranton Preparatory School, Scranton, PA (retired)

Laboratory Task Force Members

  • Chair: Kelli Slunt, University of Mary Washington, Fredericksburg, VA
  • Payton Bailey, University of Mary Washington, Fredericksburg, VA
  • Jesse Bernstein, Miami Country Day School, Miami FL (retired)
  • Alexsandra DaSilva, SUNY, Binghamton, NY
  • Myra Halpin, NC School of Science & Mathematics, Durham, NC (retired)
  • Nicolas Hamel, Clackamas Community College, Oregon City, OR
  • Innocent Pumure, University of Central Missouri, Warrensburg, MO
  • Lawrence Wilkinson, ExxonMobil, Baton Rouge, LA

Exams Annotations Volunteers

  • Editor: Qiang "Steven" Chen, Princeton International School of Mathematics and Science, Princeton, NJ
  • Annapurna Canumalla, Eastside Tutoring Academy, Sammamish, WA. National Exam 2018.
  • Harys Dalvi, American Heritage School Boca Delray, Boca Raton, FL. Local Section Exams, 2016 - 2020.
  • Andrew Ni, Amherst College, Amherst, MA. National Exam, 2017.
  • Aaron Oong, Methodist College Kuala Lumpur, Kuala Lumpur, Malaysia. National Exams, 2017-2019
  • Ron Shprints, Makif Gimmel High School, Ashdod, Israel. National  Exams 2016, 2018
  • Ritvik Teegavarapu, American Heritage School Boca Delray, Boca Raton, FL. Local Section Exams, 2016 - 2020.
  • Aditya Udgaonkar, BASIS Independent Silicon Valley, San Jose, CA. National Exam, 2016.
  • William Wu, Princeton International School of Mathematics and Science, Princeton, NJ. National Exams, 2016-2018
  • Jason Zhang, The Carol Martin Gatton Academy of Mathematics and Sciences, Bowling Green, KY. National Exam, 2016
  • Alec Zhu, Lexington High School, Lexington, MA. National Exams, 2017-2020