Given the balanced equation representing a reaction:
Cu + S==> CuS + energy
Which statement explains why the energy term is written to the right of the arrow?
(1) The compound CuS is composed of two metals.
(2) The compound CuS is composed of two nonmetals.
(3) Energy is absorbed as the bonds in CuS form.
(4) Energy is released as the bonds in CuS form.
4 is the right answer. When you form bonds energy is released, however if you were to break bonds energy is being absorbed. This scan be remembered in the simple mnemonic, BARF. Breaking, is Absorbing, Releasing, is Forming
