Alternative conceptions on gases by freshmen students from Bachelor's Degree in Chemistry at UFS / Campus São Cristóvão.

Abstract

The current paper presents the identification and understanding of alternative conceptions on gases by freshmen students from Bachelor's Degree in Chemistry at the Federal University of Sergipe, Campus São Cristóvão. The subjects are students attending the second semester of the first year in Chemistry. The data was collected by means of questionnaires in 2013/2 and 2014/2 academic semesters. The main alternative conceptions on gas were: gases are the chemical elements in the 18^th column  of the periodic table; gas is any chemical reaction involving formation of gas; gas expansion results from the increase in particle size; and gas density varies with pressure. There were also misleading representations and reasoning failure in  explaining the air thermal expansion phenomenon. Among the alternative conceptions herein identified, the conception that"gases are chemical elements" stands out with 58% of the students interpreting  gases as  noble gases. These conceptions may be related to the chemical meaning of words such as particles, atom, element, molecules and substances, as well as the way the content on gases was taught in high school.