We’re being asked to calculate the number of moles of the oxygen gas produced from a reaction that is collected over water.
Oxygen gas is the natural form of oxygen and it is a diatomic molecule (O2).
We’re going to calculate the amount of hydrogen gas in moles using the ideal gas equation.
P = pressure, atm
V = volume, L
n = moles, mol
R = gas constant = 0.08206 (L·atm)/(mol·K)
T = temperature, K
Let's first calculate the Partial Pressure of hydrogen gas:
Given: Total Pressure (Ptotal) = 744.2 mmHg
A sample of oxygen gas was collected over water. The total pressure in the collection vessel was 744.2 torr, the temperature was 26.0°C and the vessel contained 522 mL of the collected gas. How many moles of oxygen were collected? (At 26.0°C, the vapor pressure of water is 25.2 torr.)
(A) 0.231 mol
(B) 0.0201 mol
(C) 0.151 mol
(D) 0.0227 mol
(E) 0.0842 mol