Convert the vacuum pressure of 28" Hg to the corresponding absolute pressure:

To convert the vacuum pressure of 28 inches of mercury (Hg) to absolute pressure, it's important to understand the relationship between gauge pressure, absolute pressure, and atmospheric pressure. Atmospheric pressure at sea level is approximately 29.92 inches of mercury, which corresponds to about 14.7 pounds per square inch absolute (PSIA).

When you have a vacuum pressure of 28" Hg, it means that the pressure is 28 inches below atmospheric pressure. To find the absolute pressure, you subtract the vacuum pressure from the atmospheric pressure:

1. Convert the atmospheric pressure from inches of mercury to PSIA.

• 29.92 inches of mercury is approximately 14.7 PSIA.

2. Subtract the vacuum pressure from the atmospheric pressure.

• 14.7 PSIA - (29.92 inches Hg - 28 inches Hg) = 14.7 PSIA - 1.92 inches Hg.

• Since 1 inch of mercury is approximately 0.491 psi, the conversion of 1.92 inches of mercury gives around 0.943 psi.

Thus, the absolute pressure can be calculated as:

14.7 PSIA - 0.943 PSIA = approximately 13.