In fireworks (See Reactions 1-3 below), the heat released during a combustion re
ID: 1065572 • Letter: I
Question
In fireworks (See Reactions 1-3 below), the heat released during a combustion reaction (reaction 1) excites metal electrons in some salts (reaction 2). The photon of emitted electromagnetic radiation when an excited electron returns to a lower energy level is in the visible range (reaction 3). Strontium chloride emits a strong light at wavelength 641 nm and barium chloride salts have a strong emission around 493 nm. Assume all the light energy emitted comes from complete conversion of the heat energy absorbed, only one photon per atom is released, and the electron makes only one transition to emit the photon. KClO_4(s) + 3C_(graphite) + O_2(g) rightarrow KCl(s) + 3CO_2(g) + Heat Reaction 1. Heat + BaCl_2 + SrCl_2 rightarrow Ba*Cl_2 + Sr*Cl_2 (* = excited states) Reaction 2. Ba*Cl_2 + Sr*Cl_2 rightarrow BaCl_2 + SrCl_2 + light Reaction 3. What color is the light emitted by each metal as it returns to ground state?Explanation / Answer
**** Wavelength of light released by Sr is 641 nm it corresponds to Criomson red colour (mixed color of orange and red)
**** Wave length of light released by Ba is 493 nm, it corresponds to green color of light.