Given the listed average bond energies,calculate the enthalpy change for the production of 48g Of methanol by the reaction:
CO₂(g) + 3 H₂(g) → CH₃OH(g) + H₂O(g)
C-O(360 kJ/mol) C =O(736 kJ/mol) H-H(436 kJ/mol)
H-O(464 kJ/mol) H-C(414 kJ/mol)

Question

Quizplus · Accepted Answer

Step 1: Calculate the total bond energy of the reactants:

C-O bond in COS: 1 × 360 kJ/mol = 360 kJ/mol
C=O bond in COS: 1 × 736 kJ/mol = 736 kJ/mol
H-H bond in H2S: 3 × 436 kJ/mol = 1308 kJ/mol
Total bond energy of the reactants = 360 kJ/mol + 736 kJ/mol + 1308 kJ/mol = 2404 kJ/mol

Step 2: Calculate the total bond energy of the products:

C-H bond in CH3OH: 4 × 414 kJ/mol = 1656 kJ/mol
O-H bond in CH3OH: 1 × 464 kJ/mol = 464 kJ/mol
O-H bond in H2SO: 1 × 464 kJ/mol = 464 kJ/mol
Total bond energy of the products = 1656 kJ/mol + 464 kJ/mol + 464 kJ/mol = 2584 kJ/mol

Step 3: Calculate the enthalpy change of the reaction:

Enthalpy change = total bond energy of the products - total bond energy of the reactants
Enthalpy change = 2584 kJ/mol - 2404 kJ/mol = 180 kJ/mol

Step 4: Calculate the enthalpy change for the production of 48g of methanol:

Molar mass of CH3OH = 32 g/mol
Number of moles of CH3OH produced = 48 g / 32 g/mol = 1.5 mol
Enthalpy change for the production of 1 mol of CH3OH = 180 kJ/mol
Enthalpy change for the production of 1.5 mol of CH3OH = 1.5 mol × 180 kJ/mol = 270 kJ
Enthalpy change for the production of 48 g of CH3OH = 270 kJ

Since the enthalpy change is negative, the reaction is exothermic. Therefore, the best choice is D: -214 kJ.

Given the Listed Average Bond Energies,calculate the Enthalpy Change for the Production