Q.How many g of H2O are present in 0.25 mol of it ? a. 4.5 b. 18 c. 0.25 d. 5.4

Molar mass is the mass, in grams, of exactly one mole (6.022 x 10^23 entities) of a substance. For a single element, the molar mass in grams per mole is numerically identical to that element's atomic mass in u (e.g. carbon's atomic mass is 12.0u, so its molar mass is 12.0 g/mol). For a substance made of molecules or formula units, the molar mass in grams per mole is numerically identical to its molecular mass or formula mass in u (e.g. water's molecular mass is 18.0u, so its molar ma …