Question

If the water molecules in 5.70 g of water (H2O) were distributed uniformly over the surface of the Earth, how many such molecules would there be on 1.40 cm2 of the Earth's surface?
-Molar mass Hydrogen gas(H2)=2.02 g/mol
-Molar mass Oxygen gas (O2) = 32.0 g/mol
-Radius of Earth = 6370 km
-Avogadro's number = 6.02 ¡Á 1023 particles/mol
Thanks in advance !!

Answer 1

5.7g * 1mole/18.02g * 6.02*10^23 molecules/mole = 1.905*10^23 molecules

Now, multiply that by the fraction of the earth's surface, and you get

1.905*10^23 * 1.4cm^2/(5.1*10^18 cm^2)
= 52294 molecules