Problem-based learning and grade 10 students understanding of stoichiometry concepts in Yeka sub city’s secondary schools, Addis Ababa, Ethiopia

Stoichiometry is challenging for many secondary students because it requires both conceptual knowledge and mathematical reasoning. Data on structured Problem-Based Learning (PBL) for stoichiometry in Ethiopian secondary schools is still scarce. Students in Grade 10 at Yeka Sub-City in Addis Ababa took part in a five-week PBL intervention as part of this quasi-experimental study. One class (n = 78) received PBL, whereas another class (n = 80) received traditional instruction. Analysis of covariance (ANCOVA) was performed to compare post-test outcomes while taking pre-test scores into account, and independent-samples t-tests were employed to examine baseline differences. The post-test mean was lower for the comparison group (12.46 ± 2.62; t (156) = 9.94, p < 0.001) than for the PBL group (18.15 ± 4.67). There was a significant improvement in the understanding of molar ratios (F(2,75) = 8.47, p = 0.005, η ² p = 0.100), mass–mass relationships (F(4,73) = 8.68, p = 0.004, η ² p = 0.103), volume–volume relationships (F(4,73) = 31.08, p < 0.001, η ² p = 0.290), mass–volume relationships (F(3,74) = 15.61, p < 0.001, η ² p = 0.170), and limiting/excess reactants (F(4,73). Yield ideas did not significantly improve (F (2,75) = 1.33, p = 0.253, η ² p = 0.017). Overall, the model (F (16,61) = 44.06, p < 0.001, η ² p = 0.367) was significant. These findings offer context-specific data from Ethiopian secondary schools and imply that PBL may be particularly beneficial for quantitative stoichiometric connections, however yield ideas may require additional practice and scaffolding. Interpretation should take into account the small number of schools, unequal age distribution, and non-randomized design.