Bunsen Burner Efficiency
Journal of Chemical Education, Vol. 74 No. 2 February 1997
In this experiment, you will determine the efficiency of a Bunsen burner used to heat water.
The burner most commonly used in laboratories today was developed in 1854 by Robert Bunsen, a German chemist, and his laboratory assistant, Peter Desaga. The Bunsen/Desaga design generates a hot, sootless, non-luminous flame by mixing the gas with air in a controlled fashion before combustion. The gas used in this laboratory is methane, CH4.
CH4(g) + 2 O2(g) ( CO2(g) + 2 H2O(l)
ΔHr = -802.3 kJ/mol
Not all of the heat given off by the burning methane is absorbed by the water. The efficiency of a laboratory burner is the ratio of the amount of heat absorbed by the water to the amount of energy liberated by the burning methane.
% efficiency = _______heat absorbed by water______ x 100
energy given off by burning methane
heat absorbed by water (J) = (4.184 J/ g oC)(mass of water (g)) ( ΔTwater)
1 m length of rubber hose
2-L plastic soda bottle
100-mL graduated cylinder
EYE PROTECTION MUST BE WORN AT ALL TIMES
Inhalation of methane can cause dizziness. Perform this experiment in a well-ventilated laboratory, and dispose of methane as directed in the fume hood.
1. Assemble the equipment as directed by the instructor.
2. Add 100.0 mL of tap water to the beaker. Record the volume and initial temperature of the water.
3. Determine the mass of the water using the Absolute Density of Water table on my webpage.
4. Using the graduated cylinder, fill a 2-L plastic soda bottle to the very top with tap water. Record the total volume of the bottle. This will be the volume of methane gas collected by downward displacement of water.
5. Carefully invert the full 2-L bottle into a pneumatic trough filled with water. Do not allow any air i...