## Chemistry (4th Edition)

Converting mass in grams to the mole; 1 kg $Br_{2} \times\frac{1 mole Br_{2}}{159.808g}$ = 6.2575 mol. We multiply the whole reaction by 6.2575 mol. Then, $\Delta H = 6.2575mol\times-72.4 kJ/mol.$ = -453 kJ. 453 kJ heat is evolved.