Mole Concept And Molar Masses

To find the number of molecules, we need to use the number of moles formula: Hydrogen has the smallest molar mass (1 gm/mol), so 10 gm of hydrogen contains the highest number of molecules.

The molar mass of water (H O) is approximately 18 g/mol. Therefore, the number of moles in 180 grams of water is: Thus, the correct answer is 10 moles.