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)?

Answer

A, C

Explanation

Number of gram moles = `1/(18) = n`
Avogadro number, `N_A = 6.02 xx 10^23 //g - mol`
`:.` Total number of molecules,
`N = nN_A = 3.34 xx 10^22`
Number of molcules per `cm^2`
= `N(4 pi R^2)` `(R rarr "in" cm)`
= `(3.34 xx 10^22)/((4 pi)(6400 xx 5^5)^2)= 6500`.