Flame Colors as Chemical Indicators

Solutions on paper

Strips of paper towel were soaked in salt solutions and held over the flame of a laboratory burner. It was tricky to keep the paper form catching on fire, but for a brief time, you could catch the characteristic color of the metal ion. These are varieties of flames from a copper sulfate solution, but the yellow mixed in is presumably the flame color of the paper.

The potassium chloride worked very well with the paper towel strips soaked in the solution.

Strontium chloride at left gave the unmistakable red color. Copper sulfate above gave some variations in green. 左边的锶氯化物产生了 unmistakable 的红色颜色。上方的硫酸铜则产生了一些绿色的变化。

Flame Colors by CO₂ Transport

Another way to observe flame colors is demonstrated by Scott Thompson. The chloride of a metal is dissolved in hydrochloric acid and placed in a shallow dish. Marble chips are added to the dish and it is placed below a bottom-vented laboratory burner. The reaction of the acid with the marble chips releases carbon dioxide which rises through the flame and carries metal ions with it. This sample exhibits the red color of strontium. 另一种观察火焰颜色的方法由Scott Thompson演示。将金属的氯化物溶解在盐酸中，放入浅盘中。向盘中加入大理石颗粒，并将其置于底部通气的实验室燃烧器下方。酸与大理石颗粒的反应释放出二氧化碳，二氧化碳上升通过火焰并携带金属离子。该样品显示出锶的红色颜色。

Sodium 钠

Copper 铜

Strontium 锶