Introduces the principles and applications of chemistry. Topics include stoichiometry, chemical equations and reactions, chemical bonding, states of matter, thermochemistry, chemical kinetics, equilibrium, acids and bases, electrochemistry, nuclear chemistry, and descriptive chemistry of the elements. For students planning to elect further courses in chemistry, physics, and biology and to fulfill prehealth prerequisites. Prerequisites: CHEM 1410, 1610, or 1810. CHEM 1421 may be taken concurrently or after completing 1420. Drop or withdrawal from CHEM 1420, requires drop/withdrawal from CHEM 1421. C or higher required for CHEM 2410.