Cuban National Chemistry Contest 2025

This contribution compiles the problems, solutions and results of the chemistry olympiad for Cuban high school students celebrated nationwide in 2025. This year, the Cuban National Chemistry Contest (CNQ, Concurso Nacional de Química, Spanish official name) took place on February 11 and 12. The exams were designed and qualified in Havana by a scientific committee composed of selected lecturers and former students from the University of Havana, as well as international guests. Herein, the problem sets of the national exams and their solutions, and the results of the Cuban students are provided in the official Spanish version and English translation. The CNQ is an annual competition for high school students, intended to encourage the study of chemical sciences. It is sponsored by the Cuban Ministry of Education (MINED, official acronym in Spanish), the Faculty of Chemistry of the University of Havana and the Cuban Society of Chemistry. Tenth-, eleventh- and twelfth-graders (15-18 years old, on average) are welcome to participate. This event is preceded by the Municipal Contest at each high school and the Provincial Contest in every province around Cuba. Winners of the latter are invited to participate in the national event. The CNQ takes place at the Vocational High School for Exact Sciences (IPVCE, official acronym in Spanish) in every province. It is organized as a two-day competition, in which students solve two sets of theoretical or theoretical-practical problems elaborated by previous contestants and mentors. The highest scores are recognized with gold, silver and bronze medals. Top winners can select any career in science and hosting university. They are also part of the national pre-selection and are invited to Havana for a training period. After a final selection round, the national team for the International Chemistry Olympiads is formed.