Question

The pressure of a sample of gas is measured at sea level with an open-end mercury manometer. Assuming atmospheric pressure is 760.0mm Hg, determine the pressure of the gas in (a) mm Hg (b) (c) kPa.

Short answer

1. Pressure = 623mm of Hg
2. Pressure = 0.82 atm
3. Pressure = 83.05 kPa

Step-by-step solution

Define pressure

The force applied perpendicular to an object's surface per unit area across which that force is spread is known as pressure.

Converting cm of Hg pressure into mm of Hg

In the given scenario, we have an open- end manometer

P_x = pressure of gas + h

P_y = P₀

P_gas + h = P₀

P_gas = P₀ - h

P₀= Atmosphereic pressure

P_gas = gas pressure

Converting cm of Hg pressure into mm of Hg

1cm of Hg = 10 mm of Hg

13.7 mm of Hg = (13.7) × (10) mm of Hg

= 137 mm of Hg

P₀ = 760 mm of Hg

h = 137 mm of Hg

P_gas = (P₀ - h)

= (760 - 137) mm of Hg

= 623 mm of Hg

Therefore, Pressure is 623 mm of Hg

Converting mm of Hg pressure into atm 

Converting mm of Hg pressure into atm

1mm of Hg = 0.001315 atm

623 mm of Hg = (623) × (0.001315) atm

= 0.82 atm

Therefore, the Pressure is 0.82 atm

Converting mm of Hg pressure into kPa

Converting mm of Hg pressure into kPa

1mm of Hg = 0.001333kPa

623 mm of Hg = (623) ×(0.001333) kPa

= 83.05 kPa

Therefore, the Pressure is 83.05 kPa