Gas Pressure in Open-End U-Tube Manometer

[Soaring Crane]

1) What is the pressure in a gas container that is connected to an open-end U-tube manometer if the pressure of the atmosphere is 752 torr and the level of mercury in the arm connected to the container is 8.60 cm higher than the level of mercury open to the atmosphere?

a. 666 mm Hg
b. 838 mm Hg
c. 761 mm Hg
d. 743 mm Hg

Convert difference in Hg height's to mm, so 8.60 cm = 86.0 mm Hg?
Now 752 torr = 752 mm Hg. Since Hg's height is higher on gas container's side, it is 752 mm Hg - 86 mm Hg = 666 mm Hg??


2) What is the pressure (in mm Hg) of the gas inside the above apparatus (that is, the Hg height is higher than the Hg level open to the atmosphere) if the outside pressure, P_atm, is 745 mm Hg and the difference in mercury levels,delta h, is 25 mm Hg?

a. 25 mm Hg
b. 720 mm Hg
c. 745 mm Hg
d. 770 mm Hg

745 - 25 mm Hg = 720 mm Hg?

Thank you.

 

[Astronuc]

Seems to be correct.

 

[quicknote]

Your calculations are correct. In both scenarios, the pressure inside the gas container can be calculated using the formula P = P_atm + delta h, where P is the pressure inside the container, P_atm is the atmospheric pressure, and delta h is the difference in mercury levels. This is known as the manometer equation. So, in the first scenario, the pressure inside the container would be 752 mm Hg + 86 mm Hg = 666 mm Hg. And in the second scenario, the pressure would be 745 mm Hg + 25 mm Hg = 720 mm Hg. This shows that the pressure inside the container can vary depending on the atmospheric pressure and the difference in mercury levels in the manometer. As a scientist, it is important to understand and be able to calculate pressure in different systems, as it is a crucial factor in many scientific experiments and processes.