The purpose of this research study was to examine the effectiveness of problem-based learning (PBL) on eleventh grade students' understanding of "The effects of temperature, concentration and pressure on cell potential" and also their social skills. Stratified randomly selected control and experimental groups with 20 students each were used in this study. To determine their misunderstandings and misconceptions about closely related, previously covered subjects, such as oxidation-reduction reactions and electrochemical cells, interviews were conducted. Following a preparatory lesson where remediation of misconceptions were undertaken, a pre-test was given, and no significant difference was found between the two groups of students (p greater than 0.05). Then, the same teacher taught factors that affect cell potential using a teacher-centred traditional format to the control group, and a PBL format to the experimental group. Results from the post-test of both groups (p less than 0.05) showed that PBL is effective on students' achievement, remedying formation of misconceptions in a significant way. Interviews were also conducted with PBL students to determine their beliefs according to PBL activity. The findings according to interviews revealed that students in the PBL class were more motivated, self-confident, willing to problem-solve and share knowledge, and were more active in cooperative group activities than the traditionally-taught students. (Contains 8 tables and 5 figures.)