J.R. S. answered 02/17/22
Ph.D. University Professor with 10+ years Tutoring Experience
C(s) + CO2 (g) ==> 2 CO (g)
∆Hrxn = ∑∆Hproducts - ∑∆Hreactants
∆Hproducts = (2 mol x -110.5 kJ/mol) = -221 kJ
∆Hreactants = 1 mol x 0 kJ/mol + (1mol x -393.5 kJ/mol) = -393.5 kJ
∆Hrxn = -221 kJ - (-393.5 kJ) = 172.5 kJ
The molar enthalpy (in kJ/mol) for this reaction is 172.5 kJ/mol