EFFECT OF PROBLEM-BASED LEARNING ON SECONDARY SCHOOL CHEMISTRY STUDENTS' ACHIEVEMENT IN IUPAC NOMENCLATURE OF ORGANIC COMPOUNDS

This study investigated the effect of Problem-Based Learning (PBL) on secondary school students’ achievement in the International Union of Pure and Applied Chemistry (IUPAC) nomenclature of organic compounds, with a focus on gender differences in Oyo Town, Nigeria. Adopting a 2x2x2 factorial quasi-experimental design, 170 Senior Secondary II Chemistry students from two public schools were selected using purposive sampling. Participants were divided into experimental (PBL) and control (conventional lecture method) groups. The Chemistry Achievement Test (CAT), a validated and reliable instrument, was used to measure academic performance pre- and post-intervention. Results revealed a statistically significant main effect of PBL on students’ academic achievement in IUPAC nomenclature (F (1, 114) = 343.831, p < 0.05, η² = 0.765). Students in the PBL group achieved a significantly higher post-test mean score (M = 23.182) compared to those in the control group (M = 13.438), showing a mean difference of 9.744. Additionally, there was a significant main effect of gender on achievement (F (1, 167) = 4.532, p < 0.05, η² = 0.076), with female students outperforming their male counterparts (M = 21.705 vs. M = 20.353). While the interaction effect of PBL and gender was not statistically significant F(1, 112) = 1.980, p = 0.162), descriptive statistics showed that both male and female students benefited from PBL, with females in the PBL group achieving the highest post-test mean (M = 23.871). The study concludes that PBL is an effective strategy for improving students’ understanding of complex chemistry topics like IUPAC nomenclature and highlights the role of gender in learning outcomes. It recommends the integration of PBL into the chemistry curriculum and teacher training to optimize instructional practices and address gender-related learning differences.