Final answer:
To determine the number of O2 molecules needed to react with 4.87 g of S, we use stoichiometry and Avogadro's number. First, we calculate the number of moles of S using its molar mass and then convert to moles of O2 using the mole ratio from the balanced equation. Finally, we convert the moles of O2 to molecules using Avogadro's number.
Step-by-step explanation:
In order to determine the number of O2 molecules needed to react with a certain amount of S, we need to use stoichiometry. First, we need to balance the equation representing the reaction:
2S + 30₂ → 2SO₂
From the balanced equation, we can see that 1 mol of S reacts with 1 mol of O2 to produce 1 mol of SO2. To find the number of moles of O2, we first need to find the number of moles of S using its molar mass:
Molar mass of S = 32.06 g/mol
Moles of S = Mass of S / Molar mass of S = 4.87 g / 32.06 g/mol = 0.1518 mol
Since the mole ratio between S and O2 is 1:1, the number of moles of O2 needed is also 0.1518 mol. To convert this to molecules, we use Avogadro's number:
Number of molecules = Moles of O2 x Avogadro's number = 0.1518 mol x 6.022 x 10^23 molecules/mol = 9.146 x 10^22 molecules