Advanced Placement (AP) Chemistry Practice Exam

At standard temperature and pressure (STP), which is defined as a temperature of 0 degrees Celsius (273.15 K) and a pressure of 1 atmosphere, one mole of an ideal gas occupies a volume of 22.4 liters. This relationship is derived from the ideal gas law, represented by the equation PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature in Kelvin. When substituting the values for STP into this equation using R = 0.0821 L·atm/(K·mol), we can calculate the volume of one mole of gas. The calculations provide a definitive volume of 22.4 L at STP, which is widely recognized and utilized in chemistry for calculations involving gases. Thus, the knowledge that one mole of an ideal gas at STP occupies 22.4 liters is fundamental for understanding gas behavior in chemistry.