1.4 Bond Energies

Question 1

What is meant by the term ‘bond energy’?

Answer 1

The amount of energy required to break one mole of a particular covalent bond

Question 2

Is bond breaking an exothermic or endothermic reaction?

Answer 2

Exothermic

Question 3

Is bond formation an exothermic or endothermic process?

Answer 3

Exothermic

Question 4

In ______________ reactions, the energy used to break bonds is greater than the energy released by forming new bonds

Answer 4

endothermic

Question 5

In ______________ reactions, the energy released by forming bonds is greater than the energy used to break them

Answer 5

exothermic

Question 6

How do you know if a chemical reaction is endothermic or exothermic?

Answer 6

• You add up the energy it takes for the bonds on the reactants side to break, and you do the same for the products side
• Then, you do the reactants - products. If you get a minus, its exothermic

Question 7

During a chemical reaction, what three things happen?

Answer 7

• The bonds of the reactant molecules are broken
• The atoms rearrange themselves
• The bonds of the product molecules are formed

Question 8

How do you calculate the overall energy change for a reaction?

Answer 8

overall energy change = energy required to break bonds - energy released by forming bonds