A set of web-based stereochemistry tools which help students use virtual 3D models to translate Newman projections and chair conformations and assign "R/S" labels to stereocenters from 2D dashed-wedged structures is described. These tools are unique in the way they link 2D dashed-wedged structures to 3D models to help students develop visual/spatial skills. They also provide feedback on the individual parts of a student's attempt to switch between structural representations and apply the Cahn-Ingold-Prelog rules. The incorporation of these stereochemistry resources into an organic chemistry course led to improvements in students' ability to draw accurate Newman projections and chair conformations and assign "R" and "S" labels to stereocenters.