The book contains educational tasks - questions, exercises, calculated and experimental tasks, chemical dictations - of different difficulty levels. They are presented both in traditional form and in the form of tests. Tasks are given in a logical sequence of learned sections and topics without distribution by classes, because the programs of different types of schools have a different structure. It can be used for training in mastering new knowledge and skills in the lesson and at home, practicing and consolidating the learned material and the formation of specific skills during seminars, for homework and tests.