how many molecules are in18 g?

Question

how many molecules are in18 g of each of the following substances?
1-CO
2-N2
3-P4
4-P2
Do parts and contain the same number of atoms of phosphorous?


***There are 20 drops in 1 ml of water which weights one gram suppose one drop of water evaporates in one hour how many water molecules evaporate per second?

Answer 1

1 gm mole always contain the same number of molecules. Use Avogadro's number to determine how many.

For example C - 12 g/mol and O - 16 g/mol
CO - 28g/mol
1 mol has 6.022 E+ 23 atoms (or molecules) /mol so

# 0f molecules =[18 / 28 ] 6.022 E+ 23 = 3.87 E+23 molecules

Just follow the example.