Find the pressures pa and pb at surfaces a and b in the tube, respectively. use patmos to denote atmospheric pressure. express your answers, separated by a comma, in terms of one or both of the variables pgas and patmos.

The pressure on the gas in a confined space is measured using a manometer. One that is used is an open manometer

The manometer is open in the shape of a U tube and is filled with mercury liquid with both ends open. The other end is related to external pressure while the other end is connected to the room where the pressure will be measured

The height of the mercury will change when the end of the tube is connected to the room

The equation used is

P bar = atmospheric pressure

Δh = difference in mercury height

The + sign if the mercury surface at the tip is associated with the outside water is higher and vice versa, the sign - if the mercury surface is lower

The attached image states that the surface / mercury level at the end connected to the system / room is higher than the open end, by 11 cm - 5.5 cm = 5.5 cmHg, so the amount of gas pressure:

P bar = P atmos = 1 atm = 76 cmHg

P gas = P bar - h

P gas = 76 cmHg - 5.5 cmHg

P gas = 70.5 cmHg = 93992.26 Pa

or we can use the principle of hydrostatic pressure

PA = P gas, PB = Patmos = 1 atm = 101325 Pa

mercury density = 1.36 × 104 kg / m³

Δ h = 5.5 cm = 0.055 m

PA '= PB

PA + pgh = Patmos

Pgas = Patmos - pgh

PG = 101325 Pa - 1.36x10⁴ x 9.8 x 0.055

Pgas - 101325 Pa - 7330.4 Pa

Pgas = 93994.6 Pa

using a manometer to check Boyle's law

link

a manometer and a thermometer

link

the pressure of the gas in this mercury manometer

link

the pressure in the gas manifold

link

the device is called “ rocket engine”