11. Bonding & Molecular Structure

Consider the following equation:

Determine the bond enthalpy value for the F–S bond.

Use the bond energies to estimate the enthalpy of reaction for the combustion of 5 moles of acetylene:

Ethanol is a possible fuel. use average bond energies to calculate δH_rxn for the combustion of ethanol. CH₃CH₂OH(g) + 3 O₂(g) → 2 CO₂(g) + 3 H₂O(g)

Calculate the average molar bond enthalpy of the carbon–hydrogen bond in a CH₄ molecule.

Use average bond energies to calculate δHrxn for the following hydrogenation reaction: H₂C=CH₂(g) + H₂(g) → H₃C−CH₃(g)

Calculate δhrxn for the combustion of octane (C₈H₁₈) by using average bond energies.

Use average bond enthalpies to estimate the enthalpy δhrxn of the following reaction: 2 SF₄(g) + O₂(g) → 2 OSF₄(g)

Ethanol is a possible fuel. use average bond energies to calculate δH_rxn for the combustion of ethanol.

Ethanol is a possible fuel. Use average bond energies to calculate δH_rxn for the combustion of ethanol. CH₃CH₂OH(g) + 3 O₂(g) → 2 CO₂(g) + 3 H₂O(g)

2 H₃C−CH₃(g) + 7O₂(g) → 4 CO₂(g) + 6 H₂O(g)

Which of the following statements about average bond enthalpies is or are true?

a. It always requires energy to break a bond.

b. It requires more energy to break a single bond than to break a double bond.

c. Bond enthalpies can be used to estimate the reaction enthalpies of gas-phase reactions.

Which of the following statements about average bond enthalpies is or are true?

a. Bond enthalpies are always positive values.

b. When a bond is made, energy is released that is equal in magnitude to the bond enthalpy.

c. The bond enthalpy of any element in its most stable state is zero.

Gaseous iodine pentafluoride, IF5, can be prepared by the reaction of gaseous iodine and gaseous fluorine according to the following balanced equation:

I2(𝑔)+5 F2(𝑔)→2IF5(𝑔)

a. The value of Δ𝐻𝑓° for IF5(𝑔) is − 843 kJ/mol. Using this value and data in Appendix C, calculate Δ𝐻° for the preceding reaction.

b. The IF5 molecule has five I—F single bonds. Use your answer to part (a) and data in Table 5.4 to estimate the bond enthalpy 𝐷(I—F).