1) we can calculate the molecular weight of H₃PO₄
atomic mass (H)=1 amu
atomic mass (P)=31 amu
atomic mass (O)=16 amu
molecular weight (H₃PO₄)=3(1)+31+4(16)=98 amu.
1 mol (H₃PO₄)=98 g
1 mol= 6.022 10²³ molecules.
2) we calculate the mass of 4.0010²³ molecules.
98 g-------------------6.02210²³ molecules
x------------------------4.0010²³ molecules
x=(98 g 4.0010²³ molecules) / 6.022*10²³ molecules≈65 g
Answer: 65 g
