SCH 3U Combustion of Carbon Compounds Name: ______

Purpose- In this lab activity a variety of substances will be burned in order to compare complete and incomplete combustion.

Introduction-

Combustion reactions can be complete or incomplete.

Complete combustion occurs when there is sufficient oxygen to convert all of the combustible material to carbon dioxide (CO2) and water (H2O).

Characteristics: blue flame, no solids like soot (ie: a clean burn)

Incomplete combustion occurs when oxygen is insufficient and leads to hazardous (and lethal) products, especially carbon monoxide (CO), and water as usual. Many homes now have carbon monoxide detectors when heating with natural gas.

Characteristics: yellow flame, possibly solids like soot and smoke

CAUTION: All combustion reactions carry a degree of danger and must be conducted with extreme caution. All reactions will be carried out using small quantities of the combustible material and all flames must be extinguished (ie: tea light candles) once the material has been ignited. To avoid injury, all hair must be tied back and loose sleeves should be rolled up.

Materials- Bunsen burner, tea light, splint, watch glass, propane, methanol, ethanol, propanol, butanol, kerosene, paraffin wax

Procedure-

1. Combustion of propane (______: using the Bunsen burners):

Light the Bunsen burner to produce a yellow flame.

Adjust the barrel to increase the intensity of the flame (blue flame).

Which of the flames indicates complete combustion?

***For each procedural step, complete the following test to aid in the combustion classification.***

Using tongs, hold a glass plate over the watch glass without extinguishing the flame. Note any products that accumulate on the plate. Record your results.

2. Combustion of methanol (CH3OH)

Obtain about 2 mL of methanol in a watch glass. Ignite the alcohol using a splint. Observe and record the colour of the flame and the relative rate of fuel combustion.

3. Combustion of ethanol (C2H5OH)

Obtain about 2 mL of ethanol in a watch glass. Ignite the alcohol using a splint.

Observe and record the colour of the flame and the relative rate of fuel combustion.

4. Combustion of propanol (C3H7OH)

Obtain about 2 mL of propanol in a watch glass. Ignite the alcohol using a splint.

Observe and record the colour of the flame and the relative rate of fuel combustion.

5. Combustion of kerosene (camp fuel C10H22 up to C16H34; a mixture of hydrocarbons)

Obtain about 2 mL of kerosene in a watch glass. Ignite the fuel using a splint. Observe and record the colour of the flame and the relative rate of fuel combustion.

6. Combustion of paraffin wax (C18H36O2 + other products); stearic acid:

Light the tea light candle and observe the flame. Record the colour or the flame. Record your results.

Observations–

Complete a table of observations using the following format. Create a descriptive and appropriate title for your observation table.

Title: ______

Substance Combusted (name and formula) / Physical properties (state, odour, clarity, viscosity) / Observations during burning (ie. flame colour, presence or absence of soot) / Relative Rate of fuel combustion
(fast or slow) / Combustion classification (complete or incomplete combustion)

Analysis:

1. Describe complete and incomplete combustion in your own words and how you can distinguish between them.

2. Write balanced chemical equations for the combustion of the various reactants used in the lab.