Respuesta :
Answer:
The mass percent of sulfur is 9.98%.
Explanation:
The percentage of sulfur in coal can be determined by burning a sample of the solid and passing the resulting sulfur dioxide gas into a solution of hydrogen peroxide, which oxidizes it to sulfuric acid, and then titrating the acid.
The corresponding balanced equations are:
S + O₂ ⇄ SO₂ [1]
SO₂ + H₂O₂ ⇄ H₂SO₄ [2]
H₂SO₄ + 2 NaOH ⇄ Na₂SO₄ + 2 H₂O [3]
First, we have to calculate how many moles of NaOH we have.
n = 0.114 mol/L × 0.441 L = 0.0502 mol
Then, we will use the following relations:
- According to [3], 2 moles of NaOH react with 1 mole of H₂SO₄
- According to [2], 1 mole of H₂SO₄ is produced per mole of SO₂
- According to [1], 1 mole of SO₂ is produced per mole of S
- The molar mass of S is 32.0 g/mol
Then, for 0.0502 moles of NaOH:
[tex]0.0502molNaOH.\frac{1molH_{2}SO_{4}}{2molNaOH} .\frac{1molSO_{2}}{1molH_{2}SO_{4}} .\frac{1molS}{1molSO_{2}} .\frac{32.0gS}{1molS} =0.803gS[/tex]
If there are 0.803 g of S in an 8.05 g sample, the mass percent of sulfur is:
[tex]\frac{0.803g}{8.05g} .100 \%= 9.98\%[/tex]
Answer:
The mass percent of sulfur is 1.00 %
Explanation:
Step 1: Data given
Mass of the sample = 8.05 grams
Volume of a 0.114 M NaOH = 44.1 mL = 0.0441 L
Molar mass of sulfur = 32.065 g/mol
Step 2: The balanced equation
H2SO4 + 2NaOH → Na2SO4 + 2H2O
Step 3: Calculate moles NaOH
Moles NaOH = molarity * volume
Moles NaOH = 0.114 M * 0.0441 L
Moles NaOH = 0.00503 moles
Step 4: Calculate moles H2SO4
For 1 mol H2SO4 we need 2 moles NaOH
For 0.00503 moles NaOH we need 0.00503/2 = 0.002515 moles
Step 5: Calculate moles sulfur
For 1 mol H2SO4 we get 1 mol sulfur
For 0.002515 moles H2SO4 we have 0.002515 moles Sulfur
Step 6: Calculate mass of Sulfur
Mass sulfur = moles sulfur * molar mass sulfur
Mass sulfur = 0.002515 moles * 32.065 g/mol
Mass sulfur = 0.0806 grams
Step 7: Calculate % of sulfur
% sulfur = (0.0806 / 8.05)*100%
% sulfur = 1.00%
The mass percent of sulfur is 1.00 %
