In fireworks, the heat of the reaction of an oxidizing agent, such as KClO4, with an organic compound excites certain salts, which emit specific colors. Strontium salts have an intense emission at 641 nm. What is the energy (in kJ) of this emission for 7.91 g of the chloride salt of strontium? Assume that all the heat produced is converted to emitted light. Enter to 2 decimal places.