4Fe + 3O2 ---> 2Fe2O3 Delta H -1652 kJ
How much heat is released when 10 g Fe and 2 g O2 are reacted.
To determine the amount of heat released when 10 g of Fe and 2 g of O2 are reacted, we need to use the molar masses of Fe (iron) and O2 (oxygen) to convert the given masses to moles.
The molar mass of Fe is 55.85 g/mol and the molar mass of O2 is 32 g/mol.
First, let's calculate the number of moles for each substance:
Number of moles of Fe = mass of Fe / molar mass of Fe
Number of moles of Fe = 10 g / 55.85 g/mol
Number of moles of Fe ≈ 0.179 mol
Number of moles of O2 = mass of O2 / molar mass of O2
Number of moles of O2 = 2 g / 32 g/mol
Number of moles of O2 = 0.063 mol
Next, we can use the balanced chemical equation to determine the molar ratio of Fe to O2 and the heat released:
From the balanced equation: 4Fe + 3O2 → 2Fe2O3
The coefficient in front of Fe is 4, and the coefficient in front of O2 is 3. Therefore, the molar ratio of Fe to O2 is 4:3.
Since we have 0.179 mol of Fe and 0.063 mol of O2, we can determine which substance is the limiting reactant (the reactant that is completely consumed first):
The molar ratio of Fe to O2 is 4:3.
So, (4/3) mol of Fe requires 1 mol of O2.
Hence, for 0.179 mol of Fe, the moles of O2 required can be found by:
(3/4) * 0.179 mol = 0.134 mol
Since we only have 0.063 mol of O2, which is less than 0.134 mol, O2 is the limiting reactant.
Now, we can use the balanced equation and the heat of reaction provided to calculate the amount of heat released:
The heat released is given as ΔH = -1652 kJ for the reaction as written in the equation: 4Fe + 3O2 → 2Fe2O3
Since the stoichiometric ratio of O2 to Fe is 3:4, and we have determined that O2 is the limiting reactant, we can calculate the heat released using the following steps:
1. Determine the moles of Fe2O3 produced:
Moles of Fe2O3 = (moles of O2) * (2 moles Fe2O3 / 3 moles O2)
Moles of Fe2O3 = 0.063 mol * (2 mol Fe2O3 / 3 mol O2)
Moles of Fe2O3 ≈ 0.042 mol
2. Calculate the heat released using the molar ratio and the given ΔH value:
Heat released = (moles of Fe2O3) * (ΔH / 2 moles Fe2O3)
Heat released = 0.042 mol * (-1652 kJ / 2 mol Fe2O3)
Heat released ≈ -69.42 kJ (rounded to two decimal places)
Therefore, when 10 g of Fe and 2 g of O2 are reacted, approximately -69.42 kJ of heat is released.
To determine the amount of heat released when 10 g of Fe and 2 g of O2 are reacted, we need to use the given molar ratio and the molar mass of Fe and O2.
1. Calculate the moles of Fe:
Moles of Fe = mass of Fe / molar mass of Fe
The molar mass of Fe is approximately 55.85 g/mol. Therefore,
Moles of Fe = 10 g / 55.85 g/mol
2. Calculate the moles of O2:
Moles of O2 = mass of O2 / molar mass of O2
The molar mass of O2 is approximately 32 g/mol. Therefore,
Moles of O2 = 2 g / 32 g/mol
3. Determine the limiting reactant:
To find the limiting reactant, compare the moles of Fe and O2. The reactant with fewer moles will be consumed completely, while the other reactant will remain in excess. The reactant with fewer moles is the limiting reactant.
4. Calculate the moles of Fe2O3 produced:
From the balanced equation, we know that 4 moles of Fe react with 3 moles of O2 to produce 2 moles of Fe2O3.
Thus, moles of Fe2O3 = (moles of Fe) / 4 * 2
5. Calculate the heat released:
The given value, Delta H = -1652 kJ, represents the heat released for the balanced equation as written. Therefore, we can use the ratio of moles of Fe2O3 to determine the amount of heat released.
Heat released = (moles of Fe2O3) * Delta H
By following these steps, you can calculate the amount of heat released when 10 g of Fe and 2 g of O2 are reacted.