Question

Carbon reacts with oxygen to produce carbon dioxide (CO2(g), AHF = -393.5 kJ/mol) according to the equation below.

C(s) +202 (g) → CO2(g)
What is the enthalpy change of the reaction?
Use AHxn-E (AHg products) -(AHe reactan te).
393.5 kJ
196.8 kJ
196.8 kJ
393.5 kJ

Answer 1

The enthalpy change of the given reaction, which forms 1 mole of CO2, is the enthalpy of formation of CO2, thus it is -393.5 kJ.

Step-by-step explanation:

The enthalpy change of a reaction can be determined by subtracting the sum of the enthalpies of formation of the reactants from that of the products, according to Hess's Law. In the provided reaction, carbon (C(s)) reacts with oxygen (O2(g)) to form carbon dioxide (CO2(g)). The enthalpy change for the formation of one mole of CO2 from its elements in their standard states is given as -393.5 kJ/mol.

The reaction under consideration is:
C(s) + O2(g) → CO2(g) ΔHo = -393.5 kJ

Since the reaction involves the formation of 1 mole of CO2, the enthalpy change of the reaction is simply the enthalpy of formation of CO2, which is -393.5 kJ.