Flame Test

Introduction A number of common metal ions (Li+, Na+, K+, Ca2+, Ba2+, Sr2+, and Cu2+) give a distinct color to a flame. Therefore, a flame test is often used as a confirmatory test in identifying an unknown metal. Compounds of these ions provide the beautiful colors in a fireworks display. When glass is melted in a Bunsen burner flame, sodium ions color the flame. A copper wire inserted into the flame often results in a striking flame color. While the light emitted from a few excited metal ions is beautiful, in the laboratory a simple flame test is often very helpful in identifying an unknown metal ion. In this experiment you will observe and record the flame colors of several metals.

Purpose To experiment with flame tests on different salts. To predict the identity of an unknown metal ion from a flame test.

Safety Goggles Hair tied back Remain with bunsen burner at all times Perform only authorized tests

materials Salt solutions Goggles Bunsen burner QTip 11 test tubes/test tube rack

Procedures Clean 11 test tubes for your table and place them in a test tube rack Place 1mL of each solution into each of the test tubes CAUTION: Before you use the burner in the next procedures, check to see that long hair and loose clothing have been confined. Dip the tip of the clean QTip into one of the solutions, and then hold it just above the inner flame of the Bunsen burner. Observe the color of the flame just above the QTip. Heat only the tip of the QTip (burning the wooden piece may cause you to misinterpret your flame color!). Record the color of the flame in the Data Table on the next page. Test each of the remaining solutions and record the observed color in your data table. Use a new QTip each trial to make sure you do not to contaminate your samples.

Barium

Calcium

Copper

Lead

Lithium

Magnesium If you are lucky you may see it! (it makes a white flame)

Potassium

Strontium

Sodium

Unknown X

Unknown Y