The mole fraction of oxygen in dry air near sea level is 0.20948. The concentration of oxygen is __________ molecules per liter, assuming an atmospheric pressure of 739 torr and a temperature of 29.5 °C.

Question

Quizplus · Accepted Answer

To find the concentration of oxygen in molecules per liter, use the ideal gas law and mole fraction. First, convert the pressure from torr to atm (739 torr = 0.972 atm) and the temperature from Celsius to Kelvin (29.5 °C = 302.65 K). Use the ideal gas law: PV = nRT, where R = 0.0821 L·atm/mol·K. Calculate the total moles of gas per liter, then multiply by the mole fraction of oxygen (0.20948) and Avogadro's number (6.022 × 10^23) to find the concentration in molecules per liter.

The Mole Fraction of Oxygen in Dry Air near Sea