Question

number of g of oxygen in 32.2 g Na2CO3

Answer 1

i think 3 g of oxygen in 32.2g na2co3

Answer 2

Gram molecular mass of Na2CO3 = 23*2 + 12 + 16*3
                                                          = 46 + 12 + 48
                                                          = 106 g
Mass of oxygen in 106 g of Na2CO3 = 48 g
Therefore 
106 g Na2CO3 contains = 48 g oxygen
1 g Na2CO3 contains = 48/106 g oxygen
32.2 g of Na2CO3 contains = 48/106 * 32.2 = 14.58 g

14.58 g of oxygen is present in 32.2 g of Na2CO3