Formative assessments (FAs), such as muddiest point activities can capture students’ areas of confusion or struggle on given content that may otherwise be overlooked with the common FAs, such as quizzes, homework, and clickers. The few reported studies indicate mixed results on the effects of implementing the muddiest point in undergraduate STEM or chemistry courses. Additionally, the commonly reported implementation model involves the short cycle—asking the areas of confusion at the end of the lesson on instructor pre-chosen topics. Using a quasi-experimental study design, we investigated the effects of blending the muddiest point activities at each Chapter (medium cycle) with the usual common FAs on performance in the General Chemistry 1 course. In one lecture section, students were exposed to the muddiest point and the common FAs, whereas in another lecture students were exposed to the common FAs alone. Results showed students in the treatment group performed significantly (p < 0.05) better on all three midterm exams than their counterparts who were exposed to the usual common FAs only. The mean difference in the final exam was not statistically significant (p > 0.05), even though the treatment group showed a slightly higher mean score than the comparison group. MANCOVA results showed a statistically significant main effect of the FA type and statistically significant interactions between the FA type and demographic variables, particularly gender and first-generation status, and race/ethnicity and first-generation status on performance, after controlling for ACT Math scores. Between-subject tests revealed significantly higher mean scores on some midterm exams for minority, minority-first-generation, and female-first-generation students in the treatment group compared to their peers in the comparison group. The findings imply that muddiest point activities can promote equitable access to learning for all students and bolster performance, particularly for marginalized students.