Help :( If 4.7 moles of oxygen gas are allowed to react with 3.9 moles of iron according to the following equation:
4 Fe + 3 O2 → 2 Fe2O
How many moles of Fe2O3 can be formed?

Moles of Fe₂O₃ formed : 1.95

A reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.

We find the limiting reactant from the ratio of the mole and the reaction coefficient

Fe ⇒ 3.9 : 4 = 0.975

O ⇒ 4.7 : 3 = 1.56

Because the ratio of Fe is smaller, then Fe becomes the limiting reactant

Reaction

4Fe + 3O₂ ⇒ 2Fe₂O₃

mol Fe₂O₃ from mol of Fe as limiting reactant

mol ratio Fe₂O₃ : Fe = 2 : 4, then mol Fe₂O₃ :

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.