How many moles of o are in 2.45 moles of h2co3?

7.35 moles of oxygen

Explanation:

First of all, for 1 mole of H₂CO₃ we have 3 moles of oxygen (can be deduced from the chemical formula of the acid), then the moles of oxygen in 2.45 mole of the compound, which are given in the question, from the carbonic acid will be:  

If in        1 mole of H₂CO₃ we have 3 moles of oxygen

The in    2.45 moles of H₂CO₃ we have X moles of oxygen

X = ( 3 × 2.45 ) / 1 = 7.35 moles of oxygen