Sulfuric acid (H2SO4) is prepared commercially from elemental sulfur using the contact process. In a typical sequence of reactions, the sulfur is first burned:
S + O2 → SO2 ,
then it is converted to SO3 using a catalyst:
2 SO2 + O2 → 2 SO3 .
The resulting SO3 is reacted with water to produce the desired product:
SO3 + H2O → H2SO4 .
How much sulfuric acid could be prepared
from 34 moles of sulfur?
Answer in units of g
This is a regular stoichiometry problem. You can work it as three problems OR you can collapse the three into one problem with a shortcut.
Method 1: Three problems.
S + O2 ==> SO2. 34 mol S; calculate mols SO2 formed. Then
2SO2 + O2 ==> 2SO3. Use mols SO2 from the first problem and calculate mols SO3 formed.
SO3 + H2O ==> H2SO4. Use mols SO3 from second problem and calculate mols H2SO4 formed.
Method 2:
Write all of the equations.
S + O2 --> SO2
2SO2 + O2 ==> 2SO3
SO3 + H2SO4 = H2SO4.
Now watch this. Using the coefficients in the balanced equation we have
1 mol S = 1 mol SO2
2 mol SO2 = 2 mol SO3 or 1-->1
1 mol SO3 = 1 mol H2SO4
Therefore we can see that 1 mol S forms 1 mol H2SO4 and it seems obvious then that 34 mols S will produce 34 mols H2SO4.
So that would also equal 34 grams right?
No. The problem asked for mols and answer is 34 mols S. A mol of S has a mass of 32.066 grams; therefore, 34 mols will be 34 x 32.066 = a bunch of grams.
To find the amount of sulfuric acid that can be prepared from 34 moles of sulfur, we need to determine the molar mass of sulfuric acid (H2SO4) and then use stoichiometry to calculate the mass.
First, let's calculate the molar mass of sulfuric acid:
H2SO4 = 2(H) + 1(S) + 4(O)
H2SO4 = 2(1.0078 g/mol) + 32.06 g/mol + 4(16.00 g/mol)
H2SO4 = 98.09 g/mol
Now, we can use the stoichiometric coefficients from the balanced chemical equation to determine the conversion factor between moles of sulfur and moles of sulfuric acid:
From the balanced equation:
1 mole of Sulfur (S) reacts to produce 1 mole of Sulfuric Acid (H2SO4)
Therefore, 34 moles of sulfur will produce an equal number of moles of sulfuric acid.
Now, to find the mass of sulfuric acid, we can multiply the number of moles of sulfuric acid by its molar mass:
Mass of H2SO4 = Number of moles of H2SO4 × Molar mass of H2SO4
Mass of H2SO4 = 34 moles × 98.09 g/mol
Calculating this gives us:
Mass of H2SO4 = 3330.06 g
Therefore, approximately 3330.06 grams of sulfuric acid can be prepared from 34 moles of sulfur.