In one process of 5.75 kg of CaF2 are treated with an excess of H2SO4 and yield 2.85 kg of Hf calculate the percent yield of hf?
To calculate the percent yield of Hf, we can use the formula:
Percent Yield = (Actual Yield / Theoretical Yield) * 100
First, let's determine the theoretical yield of Hf.
1. Calculate the molar mass of CaF2:
Ca: 40.08 g/mol
F: 18.99 g/mol
Molar mass of CaF2 = (40.08 g/mol) + 2 * (18.99 g/mol) = 78.06 g/mol
2. Convert the mass of CaF2 to moles:
Moles of CaF2 = Mass of CaF2 / Molar mass of CaF2
Moles of CaF2 = 5.75 kg / 78.06 g/mol = 0.0737 mol
3. The balanced chemical equation for the reaction between CaF2 and H2SO4 is:
CaF2 + H2SO4 → CaSO4 + 2 HF
From the balanced equation, we can infer that 1 mol of CaF2 yields 2 mol of HF.
4. Calculate the theoretical yield of HF:
Theoretical moles of HF = 2 * Moles of CaF2 = 2 * 0.0737 mol = 0.1474 mol
5. Convert the moles of HF to mass:
Mass of HF = Moles of HF * Molar mass of HF
Hf: 178.5 g/mol
Mass of HF = 0.1474 mol * 178.5 g/mol = 26.32 g
Now, we have the theoretical yield of HF (26.32 g).
6. Calculate the percent yield:
Percent Yield = (Actual Yield / Theoretical Yield) * 100
Percent Yield = (2.85 kg / 26.32 g) * 100 = 10.8%
Therefore, the percent yield of Hf is 10.8%.
To calculate the percent yield of Hf, we first need to determine the theoretical yield of Hf and then compare it to the actual yield.
Step 1: Write a balanced chemical equation for the reaction between CaF2 and H2SO4.
CaF2 + H2SO4 → CaSO4 + 2 HF
The equation shows that 1 mole of CaF2 reacts with 1 mole of H2SO4 to produce 2 moles of HF.
Step 2: Calculate the number of moles of CaF2 used.
Given mass of CaF2 = 5.75 kg
Molar mass of CaF2 = 78.08 g/mol
Number of moles of CaF2 = mass of CaF2 / molar mass of CaF2
= 5750 g / 78.08 g/mol
≈ 73.74 mol
Step 3: Calculate the theoretical yield of HF.
From the balanced equation, the stoichiometry shows that 1 mole of CaF2 produces 2 moles of HF.
So, the number of moles of HF produced = 2 * number of moles of CaF2
= 2 * 73.74 mol
= 147.48 mol
Step 4: Convert the theoretical yield of HF to grams.
Molar mass of HF = 20.01 g/mol
Theoretical yield of HF = number of moles of HF * molar mass of HF
= 147.48 mol * 20.01 g/mol
≈ 2,951.85 g
Step 5: Calculate the percent yield of HF.
Given actual yield of HF = 2.85 kg = 2,850 g
Percent yield = (actual yield / theoretical yield) * 100
= (2850 g / 2951.85 g) * 100
≈ 96.69 %
Therefore, the percent yield of HF in this reaction is approximately 96.69%.
Do you mean HF as in hydrofluoric acid. Hf is hafnium.
Write and balance the equation.
Convert g CaF2 to mols. moles = grams/molar mass.
Use the coefficients to convert mols CaF2 to mols HF (not Hf)
Convert mols HF to g. g = mols x molar mass. This is the theoretical yield (T. E.).
%yield = (actual yield/T.E.)*100 = ?