Answer:0.021 moles
Explanation: To determine the number of moles we need to know the molar mass of the sodium phosphate, which is Na3P04. 3(Na)+1(P)+4(0)=3(22.99g/mol)=163.94g/mol
Therefore the solar mass is 163.94g/mol.
To calculate the number of moles we divide the mass by the molar mass: 3.45g/163.94g/mol=0.021 moles