The tin (II) fluoride in a 10.000 g sample of toothpaste is extracted into solution and them a precipitate of lanthanum (II) fluoride (LaF3) is formed by the addition of a lanthanum (III) nitrate solution. If the mass of the lanthanum (III) fluoride precipitate is 0.105g, what is the percentage of tin (II) fluoride in the toothpaste?
3SnF2 + 2La(NO3)3 ==> 2LaF3 + 3Sn(NO3)2
1.mols SnF2 = grams/molar mass
2.Using the coefficients in the balanced equation, convert mols SnF2 to mols LaF3.
3. Convert mols of LaF3 to grams. g = mols x molar mass. This is the theoretical yield (TY) of LaF3 from the reaction. The actual yield (AY) is 0.105 g.
4. %yield = (AY/TY)*100 = ?
To find the percentage of tin (II) fluoride in the toothpaste, we need to calculate the mass of tin (II) fluoride in the sample and then divide it by the mass of the entire sample.
Let's break down the steps to solve the problem:
1. Calculate the moles of lanthanum (III) fluoride precipitate (LaF3):
- We can determine the moles of LaF3 by using its molar mass. The molar mass of LaF3 is the sum of the molar masses of lanthanum (La) and fluorine (F).
- Mass of LaF3 = 0.105 g
- Molar mass of LaF3 = (molar mass of La) + 3 * (molar mass of F)
2. Using the stoichiometry of the reaction, determine the moles of tin (II) fluoride (SnF2) based on the moles of lanthanum (III) fluoride (LaF3):
- The balanced equation for the reaction shows that one mole of LaF3 is formed from two moles of SnF2.
- So, the moles of SnF2 = (2 moles of SnF2 / 1 mole of LaF3) x (moles of LaF3)
- Moles of LaF3, from step 1, can be used here.
3. Calculate the mass of tin (II) fluoride (SnF2) in the sample:
- We can calculate the mass of SnF2 by multiplying the moles of SnF2 (obtained in step 2) by its molar mass.
- The molar mass of SnF2 is the sum of the molar masses of tin (Sn) and fluorine (F).
4. Calculate the percentage of tin (II) fluoride in the toothpaste:
- Now, divide the mass of tin (II) fluoride obtained in step 3 by the mass of the entire sample (10.000 g in this case) and multiply by 100 to get the percentage.
Following these steps will allow us to solve for the percentage of tin (II) fluoride in the toothpaste.