Vapor pressure: Pressure exerted by a saturated vapor above its liquid in a closed container.
Three facts are important to remember:
- Vapor pressure of a substance at 100°F will always be higher than the vapor pressure of the substance at 68°F (20°C),
- Vapor pressures reported on SDSs in millimeters of mercury (mmHg) are typically very low; 760 mmHg is equivalent to 14.7 pounds per square inch (psi).
- The lower the boiling point of a substance, the higher its vapor pressure.