Question

What is the number of molecules present in 18mL of water at room temperature​

Answer 1

Desity of water is approximately 1 g/cc . So 18 ml of water weights 18 gm.

Weight = volume * density

Number of moles = weight/ molecular weight

So here in 18 gm water equal to 1 mole

So it contain 6.022*10^23 molecules ie avagadro number of molecules.