The stannous fluoride in a 10.000g sample of toothpaste was extracted and then percipitated with lanthanum nitrate solution. If the mass of the percipitate is 0.105g explain what is the percentage of stannous fluoride in the toothpaste sample?
3SnF2(aq)+2La(NO3)3(aq)---> 2LAF3(s)+3Sn(NO3)2(aq)