How many oxygen atoms are in 17.63 grams of co2?

CO₂ = 12 + 2*16 = 44 g/mol

1 mole of CO₂ contain an Avogadro number of molecules of CO₂

44g of CO₂  contain 6.02 * 10²³ molecules of CO₂

17.63g of CO₂ will contain:
                                                17.63 * 6.02 * 10²³ /44
                                         
                                                ≈ 2.412 * 10²³ molecules of CO₂

Note: 1 molecule of CO₂ has 2 atoms of O

2.412 * 10²³ molecules of CO₂ will have 2.412 * 10²³ * 2 = 4.824 * 10²³ atoms of O.

 4.824 * 10²³ atoms of O.

B"hf and f-"  is the correct answer took the test on edgenuity and got it right     

It is a mixture. simply put, a compound must be pure, that is, of only one chemical structure and composition. a mixture is made of different chemical substances (i.e. elements, molecules, compounds) that are not chemically bonded to each other, but instead physically grouped together, as in the case of gasoline (a homogeneous solution).