This study is an exploratory comparison of 69 Hispanic students enrolled in first-semester general chemistry (Chem I) who attended either a Hispanic-Serving or emerging Hispanic-Serving Institution and were not successful in Chem I. Students' automaticity skills (what can be done without the aid of a calculator) in arithmetic and quantitative reasoning were analyzed based on students' personal characteristics such as gender, prior knowledge in chemistry and mathematics, entry college (i.e., STEM or not), and parents' academic background. Findings indicate that without basic automaticity skills, students enter Chem I at a deficit, but these at-risk students can be identified early in the semester to help them succeed. Results also indicate that arithmetic automaticity is more influential than quantitative reasoning in predicting academic success. A suggested high-impact practice is presented as a possible correction for these deficits.