Answer:
The same.
Step-by-step explanation:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ molecules.
This implies that 1 mole of H2O contains 6.02×10²³ molecules and also, 1 mole of O2 contains 6.02×10²³.
From the above illustration, we can see that 1 mole of H2O and 1 mole of O2 contains 6.02×10²³ molecules respectively.
Therefore, the number of molecules in 1 mole of H2O is the same as in 1 mole of O2.