Answer:[tex]=1.156\times 10^{23}\ \text{molecules}[/tex]
Explanation:
Given
Volume of oxygen sample [tex]V=4.5\ L[/tex]
Temperature [tex]T=27^{\circ}C\approx 300\ K[/tex]
Pressure [tex]P=800\ torr\approx 1.052\ atm[/tex]
[tex][760\ torr=1\ atm][/tex]
Using ideal gas equation
[tex]PV=nRT[/tex]
Where R=universal gas constant[tex](0.0820\ L\ atm\ mol^{-1}\ K^{-1})[/tex]
n=no of moles
[tex]n=\dfrac{1.052\times 4.5}{0.0820\times 300}[/tex]
[tex]n=0.192\ mol[/tex]
So no of molecules[tex]=n\times N_a[/tex]
[tex]=0.192\times 6.023\times 10^{23}[/tex]
[tex]=1.156\times 10^{23}\ \text{molecules}[/tex]
