23 people. According to the data of biochemical competition, the list of provinces in the preliminary chemistry competition for middle school students in Tianjin in 20021year has been published, with 23 participants. The purpose of the national chemistry competition for middle school students is to popularize chemical knowledge, encourage teenagers to get in touch with the frontier of chemical development, understand the significance of chemistry to science and technology, social economy and people's lives, and learn chemists' thinking methods and working methods, thus stimulating their interest and creativity in learning chemistry.