To determine the maximum amount of moles of P2O5 that can be made from 112 g of O2 and excess phosphorus, follow these steps:
1. Write the balanced chemical equation:
P4 + 5 O2 → 2 P2O5
2. Calculate the molar mass of O2:
O2 = 2 x 16.00 g/mol (oxygen has a molar mass of 16.00 g/mol)
O2 = 32.00 g/mol
3. Calculate the moles of O2:
moles of O2 = mass of O2 / molar mass of O2
moles of O2 = 112 g / 32.00 g/mol
moles of O2 = 3.50 mol
4. Determine the stoichiometry from the balanced equation:
5 moles of O2 produce 2 moles of P2O5
5. Calculate the moles of P2O5 produced:
moles of P2O5 = (moles of O2 / 5) x 2
moles of P2O5 = (3.50 mol / 5) x 2
moles of P2O5 = 1.40 mol
The maximum amount of P2O5 that can theoretically be made from 112 g of O2 and excess phosphorus is 1.40 mol, expressed to three significant figures.