What are the number of molecules in 500cm3 of oxygen at standard conditions?

• In room condition the volume is 24dm3

So convert 500cm3 to dm3

1 dm3 equals 1000cm3

x dm3 equals 500cm3

500÷1000=0.5dm3

6.02×10^23 molecules of O2 equals 24 dm3

xmolecules equals 0.5dm3

0.5×6.02 ×10^23 ÷24= 1.25 ×10^22