Vapor pressure of gasoline at saturation

What is generally referred to is gauge pressure; absolute pressure needs to be converted as well, which is troublesome! I think it should be gauge pressure!

The national standard GB17930-2011 specifies that the vapor pressure range for 93# gasoline is: summer (5.1–10.31)

Don’t check the specifications first; there should be instructions, and it must be pressed firmly.

The pressure that is commonly referred to is usually gauge pressure, right? Does absolute pressure need to be explained separately?

Under certain external conditions, the liquid molecules in a liquid will evaporate into gas molecules, while gas molecules will also collide with the liquid surface and return to a liquid state. This is a two-phase change that occurs in a single-component system, and equilibrium is reached after a certain period of time. At equilibrium, the concentration of gaseous molecules reaches its maximum value, and the pressure generated by these gaseous molecules colliding with the liquid is referred to as vapor pressure. Vapor pressure reflects the tendency of a small number of molecules with higher energy in a solution to separate from the solution and enter space; this tendency is also known as the escape tendency. Vapor pressure is not equal to atmospheric pressure. At saturation, the vapor pressure of water in moist air is equal to the vapor pressure of pure water at that air temperature.

I can tell you for sure that it’s absolute pressure. Because the saturated vapor pressure of gasoline at room temperature is lower than atmospheric pressure.

Absolute pressure: The vapor pressure of a substance at standard pressure does not exceed one atmosphere; the critical condition is boiling. If this is gauge pressure, it means the actual pressure has already exceeded one atmosphere; in such a case, the atmospheric pressure is not sufficient to hold back the molecules trying to spread outward, so a large number of liquid molecules transform into gas molecules and escape, which is what constitutes boiling. The vapor pressure of water at 100 degrees Celsius is exactly one atmosphere, so 100 degrees Celsius is the boiling point; the vapor pressure mentioned here refers to absolute pressure.

Agreement represents absolute pressure; you can check by comparing with the specifications