Explore the fascinating world of organic chemistry in this 48-minute lecture from Yale University's Freshman Organic Chemistry course. Delve into van't Hoff's groundbreaking tetrahedral carbon models and their role in explaining optical isomers with stereogenic centers. Discover how these models predicted chiral allenes decades before their observation. Examine symmetry operations involving coordinate axis inversion and their impact on mirror-image molecules. Investigate the rarity of achiral molecules and learn about verbal and pictorial notations for stereochemistry. Journey through topics such as light rotation in optically active compounds, van't Hoff's proof of chiral allenes, chirality in relation to mirror images and handedness, and the broader implications of stereochemistry in organic chemistry.