Chemistry Flame Test

“FLAME TEST”

Theoretical Fundaments of the Experiment

The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an atom's electrons making a transition from a high energy state to a lower energy state.

This collection of different transitions, leading to different radiated wavelengths, makes up an emission spectrum. Each element's emission spectrum is unique.

Procedural Development

1. Place a little quantity of the salts from the test tubes, but big enough to take samples with the inoculation loop

2. Wash the inoculation loop in 15ml in the hydrochloric acid solution poured in a beaker

3. Introduce the graphite in the tube that contains some metallic salt in order to take a little sample from it and heat it using the Bunsen burner

4. Record your observations about the flame color. Repeat the same action with the rest of the salts be careful to clean up the inoculation loop with acid before each test

5. Observe the colors in the flame caused by the sodium and potassium salts, and then observe them through a cobalt filter.

Results

Compound Formula Color

Sodium Nitrate NaNO3.

Yellow

Calcium Nitrate Ca(NO3)2 Orange and Red

Strontium Nitrate Sr(NO3)2

Red

Potassium Nitrate KNO3

Purple and Pink

Lithium Nitrate LiNO3 Red and Purple

Copper Nitrate (II) Cu(NO3)2

Green

Three Elements that Color the Flame

Element Symbol Color

Zinc Zn Blue

Iron Fe Gold

Boron B Bright Green

Conclusions

When an element or compound is exposed to fire, the flame will change its color according the element’s valence electrons.

Source: http://en.wikipedia.org/wiki/Flame_test

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