Mass of a substance = Moles of a substance × molar mass of a substance
We have 0.94 moles of NaHCO3. The molar mass of NaHCO3 is the sum of the atomic masses of the elements comprising NaHCO3, which is approximately 84.007 g/mol.
The mass of 0.94 moles of sodium bicarbonate is therefore (0.94 moles NaHCO3)(84.007 g NaHCO3/mol NaHCO3) = 78.97 ≈ 79 grams of sodium bicarbonate.