What is the standard pressure at STP?

The standard pressure at standard temperature and pressure (STP) is defined as 1 atmosphere. This value is a key point of reference in various calculations and measurements in chemistry, particularly when discussing gas laws and behaviors. STP is commonly used in scientific contexts to provide a clear baseline for experimental conditions, where temperature is set at 0 degrees Celsius (273.15 K) and pressure is set at 1 atmosphere (101.3 kPa). This definition allows for consistent communication and analysis when dealing with gases, as it standardizes the conditions under which their properties are measured.

Other options, such as 0.5 atmospheres, 2 atmospheres, or 10 atmospheres, do not align with the established definition of standard pressure and would not provide a valid basis for scientific calculations or comparisons in the context of gas behavior at STP.