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Cleaning painted surfaces of their grime, aged varnishes, and discolored overpaint is one of the most common interventive treatments for art conservators. Carefully concocted solvent mixtures navigate the solubility differences between the material removed and the original paint underneath. However, these solutions may be altered by differential evaporation rates of the component solvents (zeotropic behavior), potentially leading to ineffectively weak cleaning or conversely overly strong residual liquid capable of damaging the underlying paint. Azeotropic solvent blends, which maintain a constant composition during evaporation, offer a promising solution. These blends consist of two or more solvents combined at precise concentrations to function as a single solvent. Additionally, pressure-maximum azeotropes feature higher vapor pressure compared to other mixtures, further minimizing contact time and sorption of the solvents into artworks. This study examines azeotropes of isopropanol with n-hexane and 2-butanone in cyclohexane, which have been used previously in art conservation. The evaporation behavior at room temperature of these boiling point azeotropes was assessed using vapor pressure measurements, refractive index determinations, gravimetric analysis, and gas chromatography. Results showed changes in composition during evaporation and found that the actual room temperature azeotropic composition can vary between 1 and 10% v/v in concentration with those commonly reported at their boiling points. Art conservators should be cautious when using azeotropic blends reported at boiling points significantly higher than room temperature. To ensure the safety and efficacy of these mixtures, it is recommended to determine individual azeotropic cleaning blends experimentally before their use. 

This investigation sought to elucidate the influence of students' academic legacy on their prior knowledge and course outcomes providing crucial insights for educators who teach general chemistry. This six-semester analysis involved 6,914 students enrolled in classes across nine Texas universities. Explored were personal circumstances associated with students' successes and failures that influenced performance in on- and off-sequence, first- and second-semester general chemistry (Chem 1 and Chem 2). Students' academic legacy based on their categorization as first generation (neither grandparent nor parent/guardian with a 4-year bachelor's degree), second generation (at least one grandparent or parent/guardian with a bachelor's degree), or third generation (at least one grandparent and at least one parent/guardian hold a bachelor's degree) was investigated. Of the students in the dataset 33.8% (n = 2,340) self-identified as Hispanic. Results for Hispanic and non-Hispanic students indicated that first-generation students struggled more with Chem 1 and Chem 2 than students in the other two legacy groups. As students' academic legacy extended, they were more apt to succeed in general chemistry. Second- and third-generation students demonstrated stronger prior high-school chemistry backgrounds and were enrolled in more advanced mathematics courses. As expected, students with stronger academic backgrounds in chemistry and mathematics scored higher on the diagnostic MUST (Math-Up Skills Test), had greater self-efficacy relative to their preparation to succeed, and reported fewer paid work hours. First-generation students on the average entered with lower diagnostic MUST scores, felt less prepared to succeed, and disclosed a greater need to be employed.