How many moles of fe2o3 are formed when 55.8 g of fe reacts completely with oxygen

Using atomic mass of Fe, 55.8g/mol, and mass of 16.7g, we find number of moles in 4Fe.

16.7/55.8 = 0.30moles of 4Fe

Now, we divide this by 2, as we have 2Fe2O3.

0.30/2 = 0.15moles of 2Fe2O3.

We use the molecular mass of 2Fe2O3 (159.6) multiplied by the number of moles (0.15moles), 159.6x0.15 = 23.94g of 2Fe2O3.

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.