1.) In a typical fireworks device, the hat of the reaction between the strong oxidizing agent, such as KCLO4, and an organic compound excites certain salts, which emit specific colours. Strontium salts have an intense emission at 631 nm, and barium salts have one at 493 nm. Part a was simple enough... Simply what are the colours. Strontium salts are essentially orange, and barium blue-green. Part b is as follows: What is the energy of these emissions for 1.0g each of the chloride salts of Sr and Ba? Assume that all heat released is converted to light emitted. I've been scanning through my lecture notes looking for an applicable equation, but E=mc^2 is reserved for nuclear reactions or relativistic rest energy, and I doubt that's what I'm looking for here... But I somewhat doubt doing a heat of formation thing would work here either. Any pointers?