Determine the pressure of the gas trapped in the apparatus shown below when the atmospheric pressure is 695 mmHg.
A)45 mmHg
B)650 mmHg
C)695 mmHg
D)740 mmHg
E)760 mmHg

Question

Determine the pressure of the gas trapped in the apparatus shown below when the atmospheric pressure is 695 mmHg. 
A)45 mmHg 
B)650 mmHg 
C)695 mmHg 
D)740 mmHg 
E)760 mmHg

Quizplus · Accepted Answer

The pressure of the gas in the apparatus is equal to the atmospheric pressure minus the pressure due to the column of liquid above it. Using the height of the column of liquid and its density, we can calculate the pressure due to the liquid column:

Pressure due to liquid column = height of column x density of liquid x gravity

= 25 cm x 1.36 g/mL x 9.81 m/s^2 x (1 cm/10^-2 m)

= 333.66 Pa

Converting to mmHg:

333.66 Pa x (1 atm/101325 Pa) x (760 mmHg/1 atm)

= 2.48 mmHg

Therefore, the pressure of the gas trapped in the apparatus is:

695 mmHg - 2.48 mmHg = 692.52 mmHg

Rounding to the nearest 10 mmHg gives us the answer of 650 mmHg.

Determine the Pressure of the Gas Trapped in the Apparatus