To calculate the heat evolved when 266g of phosphorus burns in air, we need to find the molar quantity of phosphorus and then use the given enthalpy change.
1. Find the molar mass of phosphorus (P):
Molar mass of P = 30.97 g/mol
2. Calculate the moles of P:
Moles of P = mass of P / molar mass of P
Moles of P = 266 g / 30.97 g/mol
Moles of P = 8.592 mol
3. Use the stoichiometric coefficients from the balanced equation to determine the moles of P2O3 produced:
1 mol of P produces 1 mol of P2O3 according to the balanced equation.
So, moles of P2O3 = moles of P = 8.592 mol
4. Calculate the heat evolved:
Heat evolved = moles of P2O3 * enthalpy change
Heat evolved = 8.592 mol * -367.5 kJ/mol
Heat evolved = -3155.34 kJ
Therefore, the heat evolved when 266g of phosphorus burns in air is approximately -3155.34 kJ.
calculate the heat evolved when a 266g of phosphorus burns in air according to the equation PO4 + 5O2 to form P2O3 and enthalpy change is -367.5kj/mol
1 answer
1 answer