Manometer Diagram with Barometric Pressure?

[Jay J]

Homework Statement

In the above manometer, attached to a sample of gas, the difference in the height of the mercury levels is 30.0mm. The barometric pressure is 754.0mm Hg. What is the pressure of the gas sample in kiloPascals ?

( The above figure is not drawn to scale, but the relative heights of the right and left columns of mercury are correctly shown )

Enter a numeric answer only, no units.

Homework Equations

1)If The height of the mercury level at the gas side is higher. This means that P(atm) > P(gas), So Pgas = 754 - 30 = 724 mmHg.

2)If The height of the mercury level at the atmosphere side is higher. This means that P(atm) < P(gas), So Pgas = 754 + 30 = 780 mmHg.

The Attempt at a Solution

1 mmHg = 133.3 Pa
So:

724*133.3 = 96509.2

OR

780*133.3 = 103974

what did i do wrong ?

 

[Borek]

what did i do wrong ?

You have not decided which is the correct answer.

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