9.3 Bond enthalpies Flashcards
1
Q
what is the average bond enthalpy?
A
energy required to break one mole of bonds in a gaseous molecule
2
Q
are bond enthalpies endothermic or exothermic?
A
endothermic
energy is NEEDED to break bonds
so energy is transferred from the surroundings to the system
3
Q
what are the limitations of average bond enthalpies?
A
average bond enthalpies is calculated from bond enthalpies in different environments
so it is not the actual bond enthalpy§
4
Q
bond breaking is
A
endothermic
5
Q
bond making is
A
exothermic
6
Q
why is bond breaking endothermic?
A
more energy is required to break bonds than energy released from making bonds
7
Q
why is bond making exothermic?
A
more energy is released when bonds are made than energy needed to break bonds
8
Q
equation for bond enthalpy calculations
A
reactants - products
