Energy in chemical reactions

What is the name and symbol of
the unit of energy used in energy
problems?
Is energy taken in or given out
when bonds break?
Are all bond energies the same?
Does this energy
level diagram show
an exothermic or
an endothermic
reaction?
Question 5
Is energy taken in or given out
when bonds are made?
Question 6
What do we call the minimum
amount of energy needed for a
reaction to start?
Question 7
Does this energy
level diagram show
an exothermic or
an endothermic
reaction?
Question 8
The reaction below is exothermic.
Which involves the most energy,
bond breaking or bond making?