Chemistry - Mole Concept Question with Solution | TestHub

Initial number of moles of oxygen = $0.5$

Initial number of molecules of oxygen = $0.5\times 6.022\times 10^{23}=3.011\times 10^{23}$

Number of molecules removed = $10^{22}=0.1\times 10^{23}$

Number of molecules left behind = $3.011\times 10^{23}-0.1\times 10^{23}=2.911\times 10^{23}$

Answer: $2.911\times 10^{23}$