Answer:
[tex]n=0.286mol[/tex]
Explanation:
Hello,
In this case, we consider oxygen as an ideal gas, for that reason, we use yhe ideal gas equation to compute the moles based on:
[tex]PV=nRT\\\\n=\frac{PV}{RT}[/tex]
Hence, at 3.50 atm and 25 °C for a volume of 2.00 L we compute the moles considering absolute temperature in Kelvins:
[tex]n=\frac{3.50atm*2.00L}{0.082\frac{atm*L}{mol*K}(25+273)K} \\\\n=0.286mol[/tex]
Best regards.