Why is pressure measured in millimeters of mercury?

Because most barometers employ mercury as the liquid (since it is dense and has a low vapor pressure) the height of the liquid is often used as a measure of pressure. Thus millimeters of mercury (mmHg) or centimeters of mercury (cmHg) are sometimes used as units for pressure. 1 mmHg is approximately 1 Torr.

What is mercury in pressure?

3.38639 kPa. Inch of mercury (inHg and ″Hg) is a unit of measurement for pressure. It is used for barometric pressure in weather reports, refrigeration and aviation in the United States. It is the pressure exerted by a column of mercury 1 inch (25.4 mm) in height at the standard acceleration of gravity.

How do you calculate mercury pressure?

Show the calculation supporting the claim that atmospheric pressure near sea level corresponds to the pressure exerted by a column of mercury that is about 760 mm high. The density of mercury = 13.6 g/cm3. The hydrostatic pressure is given by p = hρg, with h = 760 mm, ρ = 13.6 g/cm3, and g = 9.81 m/s2.

How does the vapor pressure of mercury affect the pressure reading of the manometer?

When mercury is used as a liquid for manometer, the vapor pressure of water at 20 °C (2.33kPa) will produce 17.5mm of height difference. Procedure for measuring the saturated vapor pressure of a pure liquid at a specific temperature.

What is the difference between millibars and inches of mercury?

CONVERTING MILLIBARS TO INCHES OF MERCURY. 1013.25 millibars is equal to 29.92 inches of mercury. These value are the average sea level pressure in each unit.

Does mercury have a low vapor pressure?

When mercury is used, mercury vapor is toxic. However, a major advantage to using mercury in a manometer is the low vapor pressure of mercury, which is 0.0017 torr at 25 °C. This small vapor pressure can be ignored for all but very low pressure measurements.