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Topic: Physical Chemistry - Gases  (Read 5915 times)

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purplebee

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Physical Chemistry - Gases
« on: June 04, 2005, 02:12:41 AM »
What is the pressure (in atm) inside a container of gas connected to a mercury-filled, open end manometer when the level in the arm is connected to the container is 28.5cm higher than the level in the arm open to the atmosphere, and the atmospheric pressure reading outside the appartus is 1.023atm?

 ??? I had totally no ideal wat formula I should apply in this question... can anyone pls help me out

Offline xiankai

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Re:Physical Chemistry - Gases
« Reply #1 on: June 04, 2005, 07:23:23 AM »
when there is no difference in the mecury level in both arms of the manometer, that means pressure is constant on both sides.

since the mecury is sucked up towards the container of gas, that implies the container of gas has a lower pressure than atmospheric pressure.

since 28.5 mm of Hg + pressure of gas = atm. pressure, and that 760 mm of Hg = 1 atm., covnert the mecury pressure to atm then do your calculations.

no formula though, just problem solving :P
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Offline eugenedakin

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Re:Physical Chemistry - Gases
« Reply #2 on: June 12, 2005, 12:02:17 AM »
Hello Purplebee,

Yes, Xiankai is quite right.  A lower pressure is inside the container than present at atmosphere.

Here are my calculations:

28.5 cm = 0.9350394 feet (U.S. Standard)

Density of Liquid Mercury =  13.5 g/cm3

pressure (psi) = 0.9350394 feet * 13.5/2.31

pressure = 5.464516 psi = 0.3718382 atm (STD)

1.023 atm - 0.3718382 => 0.651 atm

The final pressure in the container of gas is 0.651 atmospheres.

I hope this helps,

Eugene

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