If the water molecules in 1 g of water were distributed uniformaly over the surface of the earth, how many molecules would there be in `1 m^(2)` of the earth's surface (radius of the earth = 64 km)?

Explanation

Number of molecules in `1 g` of water `= (6.0 xx 10^(23))/(18)`
`:.` Number of molecules per unit area
` = (6.0 xx 10^(23))/(18 xx 4 pi (6.4 xx 10^(6))^(2))`
`= 6.6 xx 10^(8)`