If the pressure in a gas container that is connected to an open-end U-tube manometer is 126 kPa and the pressure of the atmosphere at the open end of the tube is 732 mm Hg,the level of mercury in the tube will
A)be 213 mm higher in the arm open to the atmosphere.
B)be 213 mm higher in the arm connected to the gas cylinder.
C)be 945 mm higher in the arm open to the atmosphere.
D)be 945 mm higher in the arm connected to the gas cylinder.

Question

Quizplus · Accepted Answer

To determine the level of mercury in the tube, we need to compare the pressure of the gas inside the container to the pressure of the atmosphere outside. We can use the density of mercury to convert between the units of kPa and mm Hg.

1 kPa = 7.50062 mm Hg

126 kPa = 126 x 7.50062 = 945.078 mm Hg

Therefore, the pressure of the gas in the container is equivalent to a height of 945.078 mm Hg of mercury.

Since the pressure of the atmosphere at the open end of the tube is 732 mm Hg, the level of mercury in the arm open to the atmosphere will be lower. The difference in height between the two arms of the U-tube manometer will be equal to the difference in pressure between the gas in the container and the atmosphere outside.

Difference in pressure = 945.078 - 732 = 213.078 mm Hg

Therefore, the level of mercury in the arm open to the atmosphere will be 213 mm higher than the level in the arm connected to the gas cylinder.

If the Pressure in a Gas Container That Is Connected