2 Fe2O3 → 4 Fe + 3 O2 ΔHrxn = 824.2 kJ/rxn
How much heat will occur in the decomposition of 72.7 g of Fe2O3 (FW: 159.687 g/mol)? (Write answer to a whole number, zero places past decimal point)
see the other post.
To calculate the amount of heat released in the decomposition of Fe2O3, we first need to determine the number of moles of Fe2O3 in 72.7 g of Fe2O3.
To find the number of moles, we use the formula:
Number of moles = Mass / Molar mass
The molar mass of Fe2O3 is calculated by adding the atomic masses of each element in the compound:
Fe: (2 * atomic mass of Fe)
O: (3 * atomic mass of O)
Using the atomic masses from the periodic table:
Atomic mass of Fe = 55.845 g/mol
Atomic mass of O = 15.999 g/mol
Molar mass of Fe2O3 = (2 * 55.845) + (3 * 15.999) = 159.687 g/mol
Now we can calculate the number of moles of Fe2O3:
Number of moles = 72.7 g / 159.687 g/mol
Next, we use the balanced equation to relate the number of moles of Fe2O3 to the amount of heat released. From the balanced equation:
2 Fe2O3 → 4 Fe + 3 O2
This means that 2 moles of Fe2O3 will produce 4 moles of Fe and release 824.2 kJ of heat.
To determine the amount of heat released in the decomposition of 72.7 g of Fe2O3, we can use a proportion:
(824.2 kJ / 2 moles) = (X kJ / calculated number of moles)
Solving for X, the amount of heat released:
X = (824.2 kJ / 2 moles) * calculated number of moles
Substituting the calculated number of moles:
X = (824.2 kJ / 2 moles) * (72.7 g / 159.687 g/mol)
Calculating X:
X = 373.755 kJ
Therefore, the amount of heat released in the decomposition of 72.7 g of Fe2O3 is 374 kJ (rounded to the nearest whole number).