how many atoms of oxygen are present in 4.4 grams of carbon dioxide?

Molar mass of CO2 = 44 g/mol

Moles of CO2 = 4.4 g/44 g/mol = 0.1 mol

1 mole of CO2 has 6.023x10^23 molecules, then

0.1 mol of CO2 has (6.023x10^23) (0.1) = 6.023x10^22 molecules

1 molecule of CO2 contains 2 atoms of oxygen

Therefore 6.023x10^22 molecules of CO2 contains (6.023x10^23) (2) = 1.204 x10^23 atoms of oxygen.