The number of molecules in 1.0 mole of H2O is _ as in one mole of O2

The same.

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.

they both have a y in them

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3