Groups IV, V, IVB, and VB (14 and 15)- Organometallics- Pyrophoric Carbon

Extinguishing Candles with Carbon Dioxide

Preparation and Properties of Carbon Dioxide

Colorful Stalagmites: The Silicate Garden

Samples of Silicate Minerals

Equilibrium Between Nitrogen Dioxide and Dinitrogen Tetroxide

Explosive Decomposition of Nitrogen Triiodide

Properties of Nitric Oxide

Catalytic Oxidation of Ammonia

Phosphorus Writing

Leeching Lead Into Acidic Solution

Pyrophoric Carbon

An Orange Clock Reaction

A Simple, Vivid Demonstration of Selective Precipitation

Reaction of Aluminum and Mercury (II) Chloride

Pyrophoric Carbon

Description: Carbon and potassium are heated and mixed in an air free environment. The mixture is sealed and allowed to cool. The mixture is then opened to air and poured out of the tube onto a fire-resistant surface. As the mixture falls from the tube, it combines with oxygen in the air in an exothermic reaction that produces heat, smoke and sparks as it falls. The experiment was created to demonstrate the energetics of lithium ion battery components, and the exothermic inter phase reaction between the solid mixture and the oxygen gas in the air. This effect can be amplified if the mixture is added to a tube or vessel containing pure O₂(g).

2KC₈(s) + 12O₂(g) → K₂CO₃(s) + 10CO₂(g)+ CO(g)

2KC₈(s) + 7O₂(g) → K₂CO₃(s) + 4CO₂(g)+ 3CO(g)+ 8C(s)

2KC₈(s) + 4O₂(g) → K₂CO₃(s) + 5CO(g)+ 10C(s)

The above equation assumes complete combustion. With less complete reactions, the amount of CO₂ decreases, while the incomplete combustion products, CO(g) and C(s) increase.

Source: Xiulei Ji*, Zelang Jian, Wei Luo,  Journal of American Chemical Society

Year: 2015   Vol: 137 Issue 36   Page: 11566 – 11569

Keywords: Carbon, Potassium, Redox, Combustion, Oxygen, Sparks

Rating:

Hazard: High

• Use of pyrophoric reagents
• Use of highly reactive reagents

Effectiveness: Good

• Results are observable without guidance
• Strong effects are seen by audience
• Low failure rate
• Time to results is very low
• Good connection from demo to course material

Difficulty: High

• Sequential and sensitive manipulations required
• High temperature exothermic reaction
• Use of sensitive reagents
• Use of flammable reagents
• Demos that require training to perform effectively
• Use of water sensitive reagents

Safety Precautions:

• Eye protection required
• Gloves required
• Fume hood recommended
• Thermally resistant surface
• Fire extinguisher on hand
• Perform in a well-ventilated area

Class: Group IV, V, IVB and VB (14 and 15), Metal Amalgam

Division:  Inorganic Chemistry

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