At standard conditions (1 bar or 1 atmosphere of pressure), the maximum and minimum temperature of water vapor can be determined based on its phase diagram. Water has different phases (solid, liquid, and gas) at different temperatures and pressures.
The phase diagram of water illustrates the relationship between temperature and pressure at which water exists in different states. At 1 bar pressure, the phase diagram indicates the following:
Maximum temperature: At 1 bar, water vapor can exist up to a maximum temperature known as the critical temperature. For water, the critical temperature is approximately 374 degrees Celsius or 647 degrees Fahrenheit. Beyond this temperature, water cannot exist as a distinct liquid phase, and it becomes a supercritical fluid.
Minimum temperature: At 1 bar, water vapor can exist at temperatures below the boiling point. The boiling point of water at 1 bar is 100 degrees Celsius or 212 degrees Fahrenheit. Below this temperature, water vapor will start to condense into liquid water.
Therefore, at standard conditions of 1 bar pressure, the maximum temperature for water vapor is approximately 374 degrees Celsius (647 degrees Fahrenheit), while the minimum temperature is 100 degrees Celsius (212 degrees Fahrenheit), which is the boiling point of water.