Question

Iron reacts with oxygen to form hematite in the following reaction: 2Fe(s) )Fe2O3(s) Using data from appendix 2 of the book, and assuming that heat capacities are independent of temperature, what is the reaction enthalpy at 653 K? Select one: a. +820.8 kJ b. +824.2 kJ c. -824.2 kJ d.-827.4 kJ e.-815.3 kJ f. -881.5 kJ g. -820.8 kJ h. 3410 kJ

Answer 1

Answer:

Given reaction is

2Fe(s) + (3/2)O2(g) ----------> Fe2O3(s)

Enthalpy, ∆Hrxn=sum of ∆H°f products - sum of ∆H°f reactants

∆Hrxn=(1 mol x ∆H°f Fe2O3 (s)) - [(2 mol x∆H°f Fe(s)) + ((3/2 mol) x ∆H°f O2(g))]

∆H°f Fe2O3 (s)=-824.248 kJ/mol

∆H°f Fe(s)=0 and ∆H°f O2(g)=0.

∆Hrxn=( 1 mol x -824.248 kJ/mol) -[(2 mol x 0) + (3/2 molx 0)]

∆Hrxn=-824.248 kJ

Therefore reaction enthalpy=-824.2 kJ

(c) is correct.

Please let you know if you have any doubt. Thanks