Identification of Elements: Flame Test

4. Dip the tip of the wire loop into a chemical, make sure not too much of the chemical is on the wire loop

5. Heat the tip of the wire loop in the inner part of the fire, then observe the color of the flame

6. Repeat steps 3 to 5 for the rest of the chemicals

Observations:

Analysis: To determine the unknown chemicals, two major characteristics are used. One of them is the color of the flame produced when the chemical is heated. Different chemicals react differently when being heated, and the color of flame produced by each element will be different as well. By comparing the color(s) of the flame produced by each unknown chemical with that of the other chemicals, the content of the unknown chemical will be determined. Also the shape and transparency of the crystals of each chemical may be slightly different from that of the others, so this characteristic will also help to determine what the unknown chemicals are; although the use of this is limited due to the fact that the structures and colours of most of these chemical powders were very similar.

Conclusion: Unknown A could very well be containing calcium, since the colour of its flame is orange, and the flame colours of calcium nitrate and calcium chloride are both orange. Although the flame colours of sodium chloride and sodium chloride also contain orange, but the characteristics of their powder were not the same of that of unknown A. It is really hard to determine exactly whether unknown A is calcium nitrate or calcium chloride, because all three of them had white, opaque and medium sized powders. But there is a very high chance that unknown A contains calcium. Unknown B could be potassium chloride since both of them has a pink and orange flame. Although potassium nitrate too has a pink and orange flame, but its powders did not seemed to be as fine as that of unknown B and potassium chloride. Unknown B could be potassium nitrate, but the chance of that is slim. Unknown B must contain potassium. Unknown C had a flame that was very red with a tinge of orange, which was very similar to that of strontium chloride’s flame. The flame of unknown C was also very similar to that of strontium nitrate. However, the powders of Unknown C were not as fine as that of strontium nitrate, so the chances of unknown C being strontium nitrate is slim. What is almost for certain is that unknown C contains strontium. An error that could have been made in the experiment is that the tip of the wire loop may not be cleaned thoroughly before being dipped into the next chemical. This could affect the observation of the flame color observed for the next chemical.

Post Lab Discussion Question: The flame test could be used to test unknown ionic compound powders that are hard to be determined with the human eye since some ionic compound powders are very similar in structure, transparency, and color. Plus most ionic compounds tend to form crystals, which makes it even more difficult to tell some of them apart. By using the flame test, scientists or factory workers are able to determine which chemical is which by comparing the colours of the flame produced.