Some difficulties were also found for: ● Expressions, specifically inSolve real life problems andCalculate with algebraic expressions; ● Experience with random events, specifically inCollection, editing and analysis of the results of the experiment andObservation and prediction of the event.s In the case of Chemistry, the topics considered difficult to learn online are among those in which teachers have found difficulties in teaching online and are: ● Elements in the Periodic table ● Atoms ● Chemistry general ● Solution ● Mixture and pure substances ● General and safety 40