2. A 5.000-g sample of toothpaste contains stannous fluoride and gives a 0.075-g precipitate of stannous phosphate. What is the percentage of SnF2 in the toothpaste sample?

3 SnF₂(aq) + 2 Na3PO4(aq) → Sn3(PO4)2(S) + 6 NaF(aq)