Zinc metal is added to hydrochloric acid to generate hydrogen gas,which is collected over a liquid whose vapor pressure is the same as pure water at 20.0°C (18 torr).The volume of the gas mixture is 1.7 L and its total pressure is 0.810 atm.
-Determine the partial pressure of the hydrogen gas in this mixture.
A)562 torr
B)580 torr
C)598 torr
D)616 torr
E)634 torr

Question

Quizplus · Accepted Answer

We can use the partial pressure formula to solve this problem:

P(H2) = P(total) - P(vapor pressure of water)

P(total) = 0.810 atm
P(vapor pressure of water) = 18 torr = 0.024 atm

Thus,

P(H2) = 0.810 atm - 0.024 atm = 0.786 atm

We need to convert this pressure to torr:

P(H2) x (760 torr/1 atm) = 0.786 atm x 760 torr/1 atm = 598 torr

Therefore, the partial pressure of hydrogen gas is 598 torr. Answer choice C) is correct.

Zinc Metal Is Added to Hydrochloric Acid to Generate Hydrogen