Moles of Oxygen they took in : C. 2.42
The gas equation can be written
[tex]\large{\boxed{\bold{PV=nRT}}}[/tex]
where
P = pressure, atm
V = volume, liter
n = number of moles
R = gas constant = 0.08205 l.atm / mol K
T = temperature, Kelvin
P=1000 kPa
V = 6 L
T = 298 K
moles of Oxygen :
[tex]\tt n=\dfrac{PV}{RT}\\\\n=\dfrac{1000\times 6}{8.31\times 298}\\\\n=2.42~moles[/tex]