molar mass of C2H5OH = 46.1 g/mole moles of C2H5OH = mass / molar mass = 47.0 / 46.1 = 1.02 mole 1 moles of C2H5OH contains 6.02 x 1023 C2H5OH molecules, thus, number of C2H5OH molecules = 1.02 x 6.02 x 1023 = 6.14 x 1023 C2H5OH molecules Solution molar mass of C2H5OH = 46.1 g/mole moles of C2H5OH = mass / molar mass = 47.0 / 46.1 = 1.02 mole 1 moles of C2H5OH contains 6.02 x 1023 C2H5OH molecules, thus, number of C2H5OH molecules = 1.02 x 6.02 x 1023 = 6.14 x 1023 C2H5OH molecules.