Some students struggle with chemistry because they do not find the relevance between chemistry content and their lives or they perceive their intelligence as fixed. Social-psychological interventions (SPIs), brief interventions that target students' subjective experiences, were developed to address these issues. As a result, SPIs have been associated with gains in students' academic performance, attitude, and persistence in various instructional settings; however, only a limited number of studies have explored SPIs within a chemistry context. This study evaluated the effectiveness of two SPIs, a growth mindset intervention (GMI) and a utility value intervention (UVI), on promoting students' academic performance and attitude in a general chemistry course with a large class size. This study also explored a theoretical explanation for the relationship among SPIs, attitude, and academic performance. Each SPI was designed to facilitate instructional adoption and was implemented by posting three prompts incorporated into homework assignments. The results show that the UVI led to a consistent improvement in student achievement, and among students who begin the course with lower attitudes toward chemistry, the UVI led to an improvement in students' emotional satisfaction and utility value. The UVI's improvement in academic performance was also observed with a group of students who have been underrepresented in the sciences, although a smaller sample size prevented finding statistical significance. The GMI improved academic performance relative to a comparison group but not to the extent observed with the UVI. The cost-to-benefit ratio associated with adopting SPIs within chemistry instruction seems highly favorable and thus warrants strong consideration among chemistry instructors.