When HCl(g) reacts with O2(g) to form H2O(g) and Cl2(g), 6.84 kcal of energy are evolved for each mole of HCl(g) that reacts. Write a balanced equation for the reaction with an energy term in kcal as part of the equation. Use the SMALLEST INTEGER coefficients possible and put the energy term in an appropriate box. If a box is not needed, leave it blank.