r1.2 energy cycles in reactions

Question 1

what is bond enthalpy?

Answer 1

bond enthalpy is the enthalpy change when one mole of covalent bonds, in a gaseous molecule, is broken under standard conditions
bond enthalpies are defined in terms of breaking bonds and therefore, have positive values as energy is required to overcome the forces of attraction holding the atoms together

Question 2

what is average bond enthalpy?

Answer 2

average bond enthalpy is the average amount of energy required to break one mole of a particular covalent bond in a range of gaseous molecules under standard conditions

Question 3

how do you calculate enthalpy change?

Answer 3

ΔHө = ΔHbeө of reactants = ΔHbeө of products

Question 4

what is hess’s law?

Answer 4

hess’s law states that the enthalpy route in a chemical reaction is independent of the route which is taken

Question 5

how do you calculate enthalpy change using hess’s law?

Answer 5

ΔHө = ΔHө of products - ΔHө of reactants