Given the balanced equation representing a reaction:
br2 + energy ==> br + br
which statement describes the energy change and bonds in this reaction?
(1) energy is released as bonds are broken.
(2) energy is released as bonds are formed.
(3) energy is absorbed as bonds are broken.
(4) energy is absorbed as bonds are formed.

)benzene and toluene form nearly ideal solutions. consider an equimolar solution of benzene and toluene. at 20 °c the vapour pressures of pure benzene and toluene are 9.9 kpa and 2.9 kpa, respectively. the solution is boiled by reducing the external pressure below the vapour pressure. calculate (i) the pressure when boiling begins, (ii) the composition of each component in the vapour, and (iii) the vapour pressure when only a few drops of liquid remain. assume that the rate of vaporization is low enough for the temperature to remain constant at 20 °c.