U.S. National Chemistry Olympiad Competition

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Approximately 1,000 students sit for the 3-part national exam. No more than two students from any given school can compete in the national competition. The 20 top-scoring students are chosen to attend a study camp where they will try to win a spot on the U.S. team.

National Examination

The three-part, 4.5-hour exam consists of the following (may be administered in any order):

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
  • 75 minutes
  • 2 laboratory practicals
  • Involves problem solving in the laboratory


ACS calculates the average number of correctly answered questions by topic area. Scores are ranked as follows:

  • outstanding performance
  • above average
  • average
  • below average


Students will only receive the performance ranking on Part I (multiple choice) of the exam. ACS does not distribute individual scores.

Preparing for the National Examination

Students and Teachers


  • The Olympiad Coordinators page contains detailed information, including the competition schedule and handbook.
  • The U.S. National Chemistry Olympiad Local Examination is available (for a fee) through the USNCO office. To request an order form, call 800- 227-5558 ext. 6328 or email us.
  • Be sure to provide additional questions to use as tie-breakers in the event that several students have the same score.