Question

PLEASE HELP!!!!
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
A) 6.23
B) 0.00819
C) 4.93 × 1021
D) 3.75 × 1024
E) 5.07 × 1022

Answer 1

1)convert P to atm
convet T to Kelvin
with P,T,R=0.082 atm L/mol K, and n=1 calculate the volume of one mole of air
2) Divide the molar fraction of O2 by the volume of one mole of air to calculate how many moles of O2 you have in one liter of air
3) multiply the moles of O2 per liter by Avogadro's number 6.02x10^23 to calculate the number of molecules per liter of air that has to be some of the options

Answer 2

thank you