AS chapter 6 energetics 2

 Which equation represents the change corresponding to the enthalpy change of atomization of iodine?

For which of the following reactions does the value of ΔH^Θ represent both a standard enthalpy change of formation and a standard enthalpy change of combustion?

The enthalpy change for the neutralization reaction below is − 114 kJ mol ^-1.

2NaOH (aq) + H₂SO₄(aq) ----> Na₂SO₄(aq) + 2H₂O(l)

Use this information to suggest the most likely value for the enthalpy change for the following neutralization reaction.

Ba(OH)₂ (aq) + 2HCl(aq) ----> BaCl₂(aq) + 2H₂O(l)

• − 57 kJ mol ^-1

• − 76 kJ mol ^-1

• − 114 kJ mol ^-1

• − 228 kJ mol ^-1

Which of the following processes is endothermic?

• the condensation of steam

• the freezing of water

• the decomposition of calcium carbonate into calcium oxide and carbon dioxide

• the reaction between hydrogen ions and hydroxide ions

The enthalpy changes of formation of gaseous ethene and gaseous ethane are 52 kJ mol ^-1 and − 85 kJ mol ^-1 respectively at 298 K.

What is the enthalpy change of reaction at 298 K for the following process?

C₂H₄(g) + H₂(g) ---> C₂H₆(g)

• − 137 kJ mol ^-1

• − 33 kJ mol ^-1

• + 33 kJ mol ^-1

• + 137 kJ mol ^-1

The value of the enthalpy change for the process represented by the equation

K(s) ---> K⁺(g) + e ^-

is equal to

• the electron affinity(电子亲合/吸引）of potassium

• the enthalpy change of vaporization of potassium

• the sum of the enthalpy change of vaporization of potassium and the first ionization energy of potassium

• the sum of the enthalpy change of atomization and the electron affinity of sodium

Which one of the following statements about an endothermic reaction is correct?

• The energy absorbed in bond breaking is greater than the energy released in bond forming

• The energy absorbed in bond breaking is less than the energy released in bond forming

• The energy released in bond breaking is greater than the energy absorbed in bond forming

• The energy released in bond breaking is less than the energy absorbed in bond forming

Which statement about the enthalpy level diagram below is correct?

• The reaction is endothermic

• More bonds are formed than are broken

Hydrogen reacts with chlorine to form hydrogen chloride: H₂(g) + Cl₂(g) → 2HCl(g)

Which one of the values below gives the correct value for the enthalpy change for this reaction? (Use the bond energies E(H-H) = 436 kJ mol⁻¹, E(Cl-Cl) = 243 kJ mol⁻¹, E(H-Cl) = 432 kJ mol⁻¹)

• + 185 kJ mol⁻¹

• - 185 kJ mol⁻¹

• + 92.5 kJ mol⁻¹

• - 92.5 kJ mol⁻¹

An enthalpy cycle for finding the enthalpy change of reaction ∆Hr is shown below.

Which one of these equations relating to this enthalpy cycle is correct?