When 10.00g of iron is burned in O2(g) to form Fe3O4(s), enough heat is generated to raise the temperature of 851g of water from 18.0 ∘C to 38.0 ∘C. What is the heat of formation of Fe3O4(s)?
February 20th, 2023
##DeltaH_f=-1200″kJ/mol“##
##3Fe+2O_2rarrFe_3O_4##
The heat produced:
##=mctheta=851xx4.2xx(38-18)=71484″J”##
From the equation 3mol ##Fe## produces 1mol ##Fe_3O_4##
Converting moles to grams:
##(3xx56)grarr[(3xx56)+(4xx16)]g##
##168grarr232g##
We know that:
##10grarr71484″J”##
So to form 1 mole ##Fe_3O_4##:
##168grarr(71484xx168)/(10)=1200000″J”=1200″kJ”##
Since heat is produced:
##DeltaH_f=-1200″kJ/mol”##