Question

How many molecules are in 0.5 mol?

Answer 1

If we have 2 mol of Na atoms, we have 2 × (6.022 × 10 23) Na atoms, or 1.2044 × 10 24 Na atoms. Similarly, if we have 0.5 mol of benzene (C 6H 6) molecules, we have 0.5 × (6.022 × 10 23) C 6H 6 molecules, or 3.011 × 10 23 C 6H 6 molecules. A mole represents a very large number.

Answer 2

1 mol of any compound (including of course CO2 and O2) contains 6.022*10^23 molecules

Therefore 0.5 mol of CO2 and O2 contains 3.01*10^23 molecules of each.