What is the mass of 0.61 mol of sodium chloride (NaCl)?

The molar mass of sodium chloride is the sum of the molar mass/amu of the elements sodium (Na) and chlorine (Cl), which are the atomic weights on a periodic table. The molar mass of sodium is 22.99 g/mol and the molar mass of chlorine is 35.45 g/mol, as seen on the periodic table. Molar mass of NaCl = 22.99 g/mol + 35.45 g/mol = 58.44 g/mol. Use dimensional analysis to convert from moles to mass. Since we are given moles and want to find grams, keep the molar mass in terms of g/mol. 0.61 mol NaCl * 58.44 g/mol = 35.6484 g. Since 0.61 mol has two significant figures, the mass of sodium chloride is just 36 g.

The mass has escaped into a gas which you can not see so the law stays true.