We investigated general chemistry students' intuitive ideas about the expected properties of the products of a chemical reaction. In particular, we analyzed college chemistry students' predictions about the color, smell, and taste of the products of chemical reactions represented at the molecular level. The study was designed to explore the extent to which novice learners intuitively use an additive framework to predict the properties of the product, rather than an approach that recognizes the emergent nature of the properties of chemical compounds. To this end, we used a mixed-methods research approach based on answers to multiple-choice questions and individual interviews with students enrolled in the first year of an introductory general chemistry course for science and engineering majors. Our results indicate that most students at this level rely on an additive heuristic to predict the properties of chemical compounds, overlooking the possibility of emergent properties resulting from the interaction of the atoms that compose the system. Chemistry instructors and chemical educators thus need to intentionally design learning opportunities for students to recognize and differentiate additive and emergent properties in a variety of contexts. (Contains 1 figure and 3 tables.)