Chapter 5.3

Question 1

Bond enthalpy

Answer 1

The enthalpy change when one mole of covalent bonds in a gaseous molecule is broken under standard conditions

Question 2

When are bond enthalpies used?

Answer 2

For reactions occurring in the gaseous state

Question 3

Bond breaking __ energy (__)

Answer 3

Requires, endothermic

Question 4

Bond making __ energy (__)

Answer 4

Releases, exothermic

Question 5

Why might some calculations involving bond energies be inaccurate?

Answer 5

The energies provided in tables are average values and differ between molecules

Question 6

Average bond enthalpy

Answer 6

The average amount of energy required to break one mole of covalent bonds, in gaseous molecules under standard conditions. Average refers to the fact that the bond enthalpy is different in different molecules so the value quoted is the average amount of energy to break a particular bond in a range of molecules