Students enrolled in Advanced Placement Chemistry as well as past AP Chemistry students took the 2015 Local Chemistry Olympiad Exam both yesterday and today after school.

The test, which includes 60 multiple choice questions in 110 minutes, is the first step in the American Chemical Society’s U.S. National Chemistry Olympiad competition, whose four winners will compete as the United States’ official representatives in the 2015 International Chemistry Olympiad.

“It was a great experience and posed questions whose difficulty challenged the way I think,” Parsa Shoa ’16 said.

Students whose test scores reach a certain threshold, generally slightly more than two-thirds of the questions answered correctly, will advance to the next round of the competition and take the National Chemistry Olympiad Exam in late April.

However, no more than two students from any given school can take the national exam, according to the American Chemical Society’s website acs.org.