for 2Al2O3----> 4Al(s) + 3O2

the question is what is the heat change for the formation of 1 mol of aluminum oxide from its elements?

Al2O3:-1676.0
O2:0.0

Can someone please explain how to complete this problem step by step please??

Hf for aluminum oxide is -1669.8 kJ/mole

Why are you making this so complicated?
Oxygen as an element is O2, and of course, its heat of formation is zero.

If you had asked what is the heat of formation from atoms, the question would be quite different.

what is the change in enthalpy for CH4(g) + 2O2(g)----->CO2(g)+2H20(I)

CH4: -74.86
CO2: -393.5
H2O: -285.5

I got triangle H: 890KJ/Mol is that correct?

To find the heat change for the formation of 1 mole of aluminum oxide from its elements (2Al(s) + 3/2O2), you need to use the given enthalpy values for Al2O3 and O2.

The balanced chemical equation for the formation of Al2O3 from its elements shows that 2 moles of aluminum (2Al) react with 3/2 moles of oxygen (3/2O2) to produce 1 mole of aluminum oxide (Al2O3).

Now, we can determine the heat change for the formation of 1 mole of Al2O3. This can be done by using the enthalpy values given for Al2O3 and O2.

The enthalpy of formation (ΔHf) of a compound is the heat change associated with the formation of 1 mole of the compound from its elements in their standard state.

Given that the enthalpy of formation of Al2O3 (ΔHf) is -1676.0 kJ/mol and the enthalpy of formation of O2 is 0.0 kJ/mol, we can use these values to calculate the heat change.

First, we need to consider the stoichiometry of the reaction to determine the moles of Al2O3 formed in the reaction.

For every 2 moles of Al2O3 formed, we need 2 moles of Al, and 3/2 moles of O2.

Since we want to find the heat change for the formation of 1 mole of Al2O3, we need to adjust the enthalpy values accordingly.

For the formation of 1 mole of Al2O3:
- The enthalpy change for the formation of Al (2Al) will be (2/2) * -1676.0 kJ/mol = -838.0 kJ/mol.
- The enthalpy change for the formation of O2 (3/2O2) will be (3/2) * 0.0 kJ/mol = 0.0 kJ/mol.

Therefore, the heat change for the formation of 1 mole of aluminum oxide from its elements is -838.0 kJ/mol.