How many O2 molecules are needed to react with 3.15 g of S?
To determine the number of O2 molecules needed to react with 3.15 g of S, we first need to calculate the number of moles of sulfur (S) present in 3.15 g.
1. Calculate the molar mass of sulfur (S):
1 mol of S = 32.06 g
2. Calculate the number of moles of S:
Moles of S = Mass of S / Molar mass of S
Moles of S = 3.15 g / 32.06 g/mol
Moles of S ≈ 0.0984 mol
Now, we need to find the mole ratio between S and O2 in the balanced chemical equation for the reaction between sulfur and oxygen.
The balanced chemical equation is:
2 S + 3 O2 -> 2 SO3
From the balanced equation, we can see that 2 moles of S react with 3 moles of O2.
3. Calculate the number of moles of O2 needed to react with the moles of S calculated:
Moles of O2 = Moles of S * (3 moles of O2 / 2 moles of S)
Moles of O2 = 0.0984 mol * (3/2)
Moles of O2 ≈ 0.1476 mol
Finally, we convert the number of moles of O2 to molecules using Avogadro's number, which is 6.022 x 10^23 molecules/mol.
4. Calculate the number of molecules of O2 needed:
Number of molecules of O2 = Moles of O2 * Avogadro's number
Number of molecules of O2 = 0.1476 mol * 6.022 x 10^23 molecules/mol
Number of molecules of O2 ≈ 8.88 x 10^22 molecules
Therefore, approximately 8.88 x 10^22 O2 molecules are needed to react with 3.15 g of S.