Question

0.04578 g of an unknown metal was reacted with excess HCl(aq) in a test tube to produce H₂ gas. The H₂ gas from the reaction was collected by the displacement of water at 25.0°C and the barometric pressure of 755 torr. The volume of the H₂ gas under these conditions was measured to be 17.85 mL. The water vapor pressure at 25.0°C is 23.8 mmHg. The gas constant is 0.08205 atm-L/(mol-K). 1 atm = 760 torr = 760 mmHg. What is the pressure of collected H₂ gas?

a. 0.622 atm
b. 0.729 atm
c. 0.846 atm
d. 0.964 atm

Answer 1

The pressure of the collected H₂ gas is 0.9621 atm.

Step-by-step explanation:

To find the pressure of the collected H₂ gas, we first need to convert the barometric pressure from torr to atm. Using the conversion factor 1 atm = 760 torr, the barometric pressure of 755 torr is equivalent to 0.99342 atm. Next, we need to subtract the water vapor pressure at 25.0°C, which is 23.8 mmHg, from the barometric pressure in atm. Converting the vapor pressure from mmHg to atm using the conversion factor 1 atm = 760 mmHg, we get 0.03132 atm. Finally, we subtract this vapor pressure from the barometric pressure to get the pressure of the collected H₂ gas, which is 0.99342 atm - 0.03132 atm = 0.9621 atm.