National Chemistry Olympiad Exam

Number of Nominees

More than 1,000 students sit for the three-part National Exam each April. Coordinators nominate students for the National Exam based on the results of the Local Competitions. Each Local Section can nominate only a certain number of students determined by the number of its ACS members.

Students during the Chemistry Olympiad laboratory exam
ACS Members USNCO Nominees ACS Members USNCO Nominees

1–1000

1001-1350

1351-1700

1701-2050

2051-2400

2401-2750

2751-3100

3101-3450

3451-3800

3801-4150

10

11

12

13

14

15

16

17

18

19

4151-4500

4501-4850

4851-5200

5201-5550

5551-5900

5901-6250

6251-6600

6601-6950

6951-7300

7301-7650

20

21

22

23

24

25

26

27

28

29

The national examination is scheduled to be given during the period of nine consecutive days.

No more than two students from any given school can compete in the National Exam. The 20 top-scoring students are invited to attend a study camp to compete for a spot in the U.S. team.

National Exams are often hosted by ACS Local Sections at local universities and colleges. ACS Local Sections recognize USNCO National Exam nominees with certificates, monetary prizes, plaques, or other gifts. Many Local Sections honor the students, their teachers, parents and volunteers at award banquets, luncheons and dinners.

National Examination Administration

The three-part, 4 hour and 45 minutes 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
  • 90 minutes
  • 2 laboratory practicals
  • Involves problem solving in the laboratory

How to Prepare

Students can use the past National Exams as guidance to help them study for the tests. Past IChO Exams can also be used in preparation, as each year's study camp curriculum is based on preparatory problems posted by the host country.

Scoring

ACS calculates the average number of correctly answered questions by topic area. Based on this average, each student's score in a particular topic is compared to the overall average and rated as: Below Average, Average, Above Average, or Outstanding Performance.

Only student scores for Part I (multiple-choice) are sent to the Local Section coordinators to be distributed to students.

Results

Based on the score of their overall performance, the top 150 students are recognized as high Honors and Honors and receive a certificate from the USNCO national office. The top 50 students are recognized as High Honors and the next 100 as Honors. The list of High Honor and Honor students is published on the USNCO website.