Chemistry Lab: Flame Tests
Friday, September 19th, 2014
Objective:
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.
Materials:
• Bunsen burner
• Scoopula
• 250mL beakers
• Barbecue lighter
• Wooden splints soaked in water
• Distilled water
• Potassium nitrate
• Sodium nitrate
• Copper (II) acetate
• Strontium nitrate
• Sodium chloride
• Barium nitrate
• Calcium carbonate
• Copper (II) nitrate
• Unknown substances #1-4
• Mixture
Safety:
• Wear goggles
• Tie back long hair
• Do not wave splints
• Do not allow to splint to ignite
• Rinse used splints in cold tap water before disposing in garbage can
Procedure:
1. Obtain 11 pieces of scrap paper. Label them with the eight solids you will be testing and one labeled "mixture". Label the last two papers "unknown".
2. Pour a small amount of the crystals on the labeled papers.
3. Take a wet wooden splint and dip the wet end into a pile of crystals. (The splint should not burn, only the chemicals.)
4. Hold the crystals in the Bunsen burner flame and observe the color of the flame above the splint.
5. Record the color in the data chart.
Questions
1. Is the flame colour determined by the positive metal ion or the negative ion in the compound? Explain how you made your decision based on the data.
It is the positive ion that determines the flame colour. I made this decision based on how flame colour changes with the metal. For example, both sodium samples had an orange flame colour and both copper samples had a green flame colour. Whereas the four nitrates all burned different colours.
2. What colour would you expect CaCl2 to produce in a flame? Why?
I would expect little orange when calcium chloride is burned because though our calcium carbonate had little colour change, it still did have a few orange flames and I believe we did just not use enough crystals. Both calcium...