Works the same way as dG but this is dH.
Write ad balance the equation.
dHrxn = (n*dHo products) - (n*dHo reactants). Of course you will need ton convert 25 lbs to grams.
Write ad balance the equation.
dHrxn = (n*dHo products) - (n*dHo reactants). Of course you will need ton convert 25 lbs to grams.
The reaction can be represented as follows:
4P + 5O2 -> P4O10
We need to find the enthalpy of formation (ΔHf) values for P4 and P4O10.
1. Look up the value for the enthalpy of formation of P4 from the appendix of your textbook. Let's assume it is -263.2 kJ/mol.
2. Look up the value for the enthalpy of formation of P4O10 from the appendix of your textbook. Let's assume it is -2943.8 kJ/mol.
3. Calculate the number of moles of white phosphorus (P4) in the 25.0 pound artillery shell. We need to convert the mass of the shell to moles using the molar mass of P4.
The molar mass of P4 is 4 * (atomic mass of P) = 4 * 30.974 g/mol = 123.896 g/mol.
25.0 pounds = 25.0 * 0.453592 kg = 11.3398 kg.
Convert to grams: 11.3398 kg * 1000 g/kg = 11339.8 g.
Convert to moles: 11339.8 g / 123.896 g/mol = 91.4402 mol.
4. Calculate the change in enthalpy (ΔH) for the reaction using the formula:
ΔH = (ΔHf of P4O10 - ΔHf of P4) * number of moles.
ΔH = (-2943.8 kJ/mol - (-263.2 kJ/mol)) * 91.4402 mol.
5. Convert the result to mega-joules (MJ). There are 1000 kJ in 1 MJ.
ΔH = (△H) / 1000 = (result) kJ = (result) MJ.
Follow these steps to find the values in your textbook appendix and perform the necessary calculations to obtain the change in enthalpy in mega-joules (MJ).