Question

CO + 2H2 ⇌ CH3OH ΔH <0

The synthesis of CH3OH(g) from CO(g) and H2(g) is represented by the equation above.

Which of the following statements is true about bond energies in this reaction?

a. The energy absorbed as the bonds in the reactants are broken is less than the energy released as the bonds in the product are formed.
b. The energy released as the bonds in the reactants are broken is less than the energy absorbed as the bonds in the product are formed.
c. The energy released as the bonds in the reactants are broken is greater than the energy absorbed as the bonds in the product are formed.
d. The energy absorbed as the bonds in the reactants are broken is greater than the energy released as the bonds in the product are formed.

Answer 1

C. The energy released as the bonds in the reactants are broken is greater than the energy absorbed as the bonds in the product are formed.

Step-by-step explanation:

• CO + 2H₂ ⇌ CH₃OH ΔH <0

As ΔH is negative, the given reaction is exothermic.

That means that the enthalpy of the product is less than the enthalpy of the reactants. In other words, part of the energy from the reactants is used to form new bonds (between C and H, for example), while the other part is transfered outside the system as heat.

Thus the correct answer is C.