Question

1. What wavelengths are associated with the light color observed in each metal’s flame test?

2. What are the most probable atoms in your unknown solid based on the observed light emissions?
3. Sodium light is easy to filter because it only emits light at a specific wavelength. Would any of the other metals you tested also be easy to filter? Why or why not?
4. If a fireworks engineer was planning a Christmas show and wanted to create a red explosion followed by a green one. Based on the flames observed, which metal salts should they use?

The metal salts I used to test were Potassium Chloride, Lithium Chloride, Copper Chloride, Sodium Chloride, and an Unknown Salt.

Answer 1

Here's what I get

Explanation:

1. Wavelengths

`\begin{array}{lcc}\textbf{Salt} & \textbf{Flame Colour} & \mathbf{\lambda} \textbf{/nm}\\\text{KCl} & \text{violet} & 423\\\text{LiCl} & \text{red} & 701\\\text{CuCl}_(2) & \text{blue-green} & 492\\\text{NaCl} & \text{ orange-yellow} & 590\\\end{array}`

2. Identity of unknown

Don't know. You haven't told us its flame colour.

3. Light filters

You could probably filter lithium light. It is almost pure red.

The other elements emit light of mixed colours. It would be difficult to filter them with filters of a single wavelength.

4. Fireworks chemicals

For a red explosion followed by a green one, the engineer should use LiCl and CuCl₂.