Vapor pressure is usually expressed in which units?

Vapor pressure is usually expressed in which units?

• A. Atmospheres.
• B. Bar.
• C. Millimeters of mercury (mmHg) or pounds per square inch (psi).
• D. Pascals.

Answer: (C)

Vapor pressure is a pressure, the force exerted by a vapor in equilibrium with its liquid. Because it is a pressure, it’s expressed using units that quantify pressure. Millimeters of mercury (mmHg), a traditional and widely used unit in chemistry and safety data, and pounds per square inch (psi), common in U.S. industry and hazmat contexts, are the two most typical ways to report vapor pressure. While other pressure units like atmospheres, bars, or pascals can describe the same quantity, mmHg and psi are the ones you’ll encounter most often in hazmat settings, which is why they’re considered the best answer. Quick reminders: 1 atm equals 760 mmHg, and 1 psi is about 6895 Pa.

Vapor pressure is a pressure, the force exerted by a vapor in equilibrium with its liquid. Because it is a pressure, it’s expressed using units that quantify pressure. Millimeters of mercury (mmHg), a traditional and widely used unit in chemistry and safety data, and pounds per square inch (psi), common in U.S. industry and hazmat contexts, are the two most typical ways to report vapor pressure. While other pressure units like atmospheres, bars, or pascals can describe the same quantity, mmHg and psi are the ones you’ll encounter most often in hazmat settings, which is why they’re considered the best answer. Quick reminders: 1 atm equals 760 mmHg, and 1 psi is about 6895 Pa.