This lecture introduces the fundamentals of chemical engineering, covering topics such as material balances, energy balances, stoichiometry, and reactive mass balances. It explains key concepts like limiting reactants, conversion, and selectivity through examples and calculations. The lecture also delves into the importance of yield in chemical reactions and demonstrates how to apply mass balances on reactive systems. Students will learn how to extract quantitative information from stoichiometry, determine the limiting reactant, calculate conversion rates, and assess the selectivity of reactions.