Question

Calculate the number of molecules in 100 ml of water

Answer 1

the density of water is 1g/mL, 100mL of water= 100g water.

Molar mass H2O = 18g/mol

Number of moles = 100/18 = 5.56 mol

Number of molecules:

1 mol = 6.022/10^23 molecules

5.56 mol = 5.56*6.022*10^23 = 3.35*10^24 molecules.​​​​​​​