Answer:
731.25 g
Explanation:
The question asks us to calculate the mass of 12.5 moles of NaCl. The individual relative atomic masses of the elements were supplied. We must first obtain the molar mass of sodium chloride as follows;
Molar mass of sodium chloride= 23.0 + 35.5 = 58.5 gmol-1
From the formula;
Number of moles (n) = mass /molar mass
Number of moles of sodium chloride= 12.5 moles
Mass of sodium = The unknown
Molar mass of sodium chloride= 58.5gmol-1
Mass of sodium chloride= number of moles × molar mass
Mass of sodium chloride= 12.5 × 58.5
Mass of sodium chloride= 731.25 g
