Chemistry – flame coloration

The science of chemistry is one of the most interesting sciences out there. Although some people probably wouldn’t agree with chemistry being that interesting because chemistry isn’t as simple as most would like it to be, but I think most people will agree that scientific experiments related to chemistry are among the most interesting ones. One of these experiments is the flame test, which is often used as an interesting presentation or introduction to general chemistry, but it also has a practical value in analytical chemistry because it is used to find and identify various metals or ions. Since the flame colorations for most metals and ions are known, one can easily determine what particles are present in a sample that is tested.

The test usually involves introducing a sample of the compound or element to a non-luminous and hot flame, and observing the coloration of the flame that occurs. Samples are usually held on a small piece of platinum wire that was previously cleaned with hydrochloric acid, to make sure all traces of previous compounds that were analyzed are removed.

One of the most known chemicals that are used as flame colorants are various copper, sodium, potassium, caesium and strontium compounds. When a compound that contains copper (like copper sulphate) gets in contact with a flame, the flame gets blue-green colored. In the case of sodium (by introducing sodium nitrate) the, flame gets bright yellow-orange colored. Potassium (for example, by introducing potassium nitrate) is known to make the flame lilac colored, and caesium (by introducing caesium nitrate) colors the flame in a nice blue-violet color. Strontium is also often used, because it colores the flame in a bright and clear red color. Most often used compound of strontium is strontium nitrate, along with strontium carbonate.

There are also many other chemical compounds that can color flames, but these were just examples of compounds that are most well known and most commonly used. If one is more interested in finding about more behind the reactions that occur at flame coloration tests, you can look up websites with chemistry related lessons to find out more.