STUDENTS DIFFICULTIES IN UNDERSTANDING OF THE CONSERVATION OF MATTER IN OPEN AND CLOSED-SYSTEM CHEMICAL REACTIONS
Abstract
The law of conservation of matter is a cornerstone in the development and advancement of modern chemistry. With this idea in mind, a test of four items was designed and used to determine students understanding about the conservation of matter in open and closed-system chemical reactions. The test was administered to 150 lycee-2 (grade 10; age 15-16) students after they studied the unit on chemical reactions. The analysis of the collected data revealed that students had some misconceptions. One of the most common misconception encountered was that the total mass increases in a precipitation reaction because the precipitate produced is solid and it is heavier than a liquid. Another misconception in parallel to the previous one was that when a chemical combustion happens in a closed system, the total mass decreases. [Chem. Educ. Res. Pract.: 2003, 4, 279-290]