This lecture provides an overview of thermodynamic systems, focusing on state variables and state functions. The instructor begins by defining what constitutes a thermodynamic system and its environment, emphasizing the importance of understanding the types of exchanges that can occur. Three types of systems are introduced: open, closed, and isolated, each characterized by their ability to exchange matter and energy with their surroundings. The lecture then delves into state variables, distinguishing between intensive and extensive variables, and explaining their significance in defining the state of a system. The instructor discusses the ideal gas equation and its implications, illustrating how pressure, volume, and temperature are interrelated. The concept of state functions is also introduced, highlighting their independence from the path taken during a transformation. The lecture concludes with practical examples, including Boyle's Law and Charles' Law, demonstrating how these principles apply to real-world scenarios in thermodynamics.