Guided-inquiry experiments offer the same opportunities to participate in the process of science as classical organic qualitative analysis used to do. This three-week guided-inquiry project involves an aldol-dehydration synthesis of a chalcone chosen from a set of nine, followed by a catalytic transfer hydrogenation reaction using ammonium formate and Pd/C. The question each two-student team addresses is "Which of the functional groups of a multifunctional chalcone undergo hydrogenation in the reaction?" The regioselectivity is discovered by IR, NMR, and GC-MS spectrometric analysis. Students present their experimental results and conclusions to the entire lab section in a post-laboratory discussion held during the third week of the project, before their written results are due. The chalcone project was assessed at a large university in a laboratory class of 550 organic chemistry students using graduate-student teaching assistants. Student feedback was heavily favorable, both on the use of spectroscopy to determine the selectivity of hydrogenation and on the value of the post-lab discussion. The TA training and the faculty response are also discussed. (Contains 5 tables.)