Chemistry Lab: Flame Tests
Friday, September 19th, 2014
The purpose of this lab was to see how, when in a flame, different compounds burn in particular colours to aid us in discovering the identity of the substance.
â€¢ Bunsen burner
â€¢ 250mL beakers
â€¢ Barbecue lighter
â€¢ Wooden splints soaked in water
â€¢ Distilled water
â€¢ Potassium nitrate
â€¢ Sodium nitrate
â€¢ Copper (II) acetate
â€¢ Strontium nitrate
â€¢ Sodium chloride
â€¢ Barium nitrate
â€¢ Calcium carbonate
â€¢ Copper (II) nitrate
â€¢ Unknown substances #1-4
â€¢ Wear goggles
â€¢ Tie back long hair
â€¢ Do not wave splints
â€¢ Do not allow to splint ...view middle of the document...
Both calcium chloride and calcium carbonate have the same positive metal ion so I would expect them to burn almost the same colour.
3. Some strontium compounds are used in the production of fireworks. What colour would you predict for such fireworks?
I would expect fireworks that contain strontium to be red.
4. How could you distinguish the following white artificial sweetener powders using flame tests: Equal (C14H18N2O5- a non-ionic compound), Ace-K (K+C3H4NO4S-) and Sweet `N Low (Ca2+[C7H4NO3S-]2)?
Ace-K has potassium which would burn purple. Sweet 'N Low has calcium which would burn red. Equal has no ionic compounds so would not produce any colour.
5. Glass contains sodium compounds. How does this explain what happens to the colour of a flame when fire polishing glass?
When fire polishing glass, the flame turns yellow. This is explained by the way the sodium compound burned yellow in the flame test.
6. Salt substitutes such as "No Salt" produce pink or violet colours in a flame test. What ion do they likely contain?
If they burn purple or pink, they likely contain the potassium ion.
7. The splints used in this lab were soaked in distilled water rather than tap water. Why?
The splints used were soaked in distilled water instead because tap water can sometimes contain some minerals of its...