Using a Bunsen Burner
Introduction:
The Bunsen burner is the most common source of heat in the chemistry laboratory. Natural gas
enters the burner near the base, rises through a barrel, mixes with air, and burns. By proper
adjustments the most efficient flame can be obtained.
The typical Bunsen burner contains the parts shown in Figure 1. Variations such as a combination
collar and barrel are often seen. Look at your burner and identify each of the parts shown in
Figure 1. Gather the materials given in the list below and begin your investigation of the problem.
Figure 1: Parts of a Bunsen Burner
Pre-lab:
Answer the Prelab Questions in your science journal (read the Introduction and Procedure to help
you find the answers).
1. Draw a Bunsen burner in your science journal and label its parts.
2. What is the proper color for a burner flame?
Materials:
Safety goggles
Bunsen burner
Tripod
Wire gauze
Beaker tongs
Thermometer
250 mL beaker
100 mL graduated cylinder
Heatproof mat
Safety:
Wear safety goggles whenever working in the laboratory.
When using a Bunsen burner:
Tie back long hair and remove loose clothing
Never leave a burner unattended
Do not reach over a lit burner
Make sure no flammables are near the burner
Procedure
Part 1: Use of the Burner
Setting the flame
1. Be sure the hose is securely fastened to both the burner and the gas outlet.
2. Light your match, then turn on the gas to the maximum open position. Light the burner
with the match by holding the match just off to the side of the top of the barrel.
3. The flame height can be adjusted by turning the needle valve.
4. The flame color can be adjusted by turning the barrel (or opening the air vents).
5. If the flame is a yellow color, it is not getting enough air. Use the barrel and air ports to
adjust it until it is completely blue and shows an inner cone as illustrated in the picture
shown to you by your teacher. Too much air will cause the flame to be noisy and possibly
blow out.
6. If the flame is blue without an inner cone, adjust the barrel or air ports until an inner cone
is visible.
Heating a liquid
To heat large amounts of water use the set-up shown in figure 2 below. Assemble this apparatus
now (without the beaker) for use in the next part of your investigation.
Figure 2: Tripod setup
Part 2: Efficiency of the Bunsen Burner
Make a Data Table for this section in your science journal with the headings shown below:
Location of Beaker in
the Bunsen Burner
Flame
Trial 1: Top of flame
heats bottom of beaker
Trial 2: Top of inner blue
cone heats bottom of
beaker
Initial
temp. of
water
(˚C)
Temp. of
water
(˚C) at 1
min.
2
minutes
3
minutes
4
minutes
5
minutes
6
minutes
7
minutes
1. Light the burner and adjust the flame properly.
2. For each trial measure 80.0 mL of water using a graduated cylinder and pour it into the
beaker.
3. Take the initial temperature of the water and record in your data table.
4. Place the burner under the beaker and heat the water for 7 minutes taking the
temperature of the water every minute.
a. NOTE: For each temperature reading the temperature will change very rapidly
when the thermometer is first placed in the water. Wait to record the temperature
until the rate of change is slow. After recording your data, remove the
thermometer and carefully place it on the table.
5. After the last temperature reading remove the burner from under the beaker. Remember
not to turn it off!
6. Carefully remove the beaker (use tongs) from the stand and set it on the lab bench to cool.
7. Record the initial temperature of the water in your second beaker and it onto the tripod.
Place the burner below, and adjust the height of the flame so that the bottom of the
beaker is heated by the inner cone.
8. Repeat steps 3 - 5 for trial 2. Be sure to record the data after each measurement.
Cleaning Up:
If your glassware has cooled sufficiently, pour the water down the sink and dry your beakers.
Leave the lab station just as you found it!
Analysis:
1. Make a graph of temperature versus time on a separate sheet of graph paper (this will be
turned in for a grade). Plot time on the x- axis (horizontal) and the water temperature for
each flame location on the y-axis (vertical). Draw a line of best fit for each set of data.
2. Which line shows the most efficient heating of the water? Explain why you chose this line.
3. Where is the hottest part of the blue flame? Check your answer using the diagram below.
4. What are the advantages of using a blue flame instead of a yellow one for heating objects
in the laboratory?
5. When heating a substance over a Bunsen burner where should the object be placed for
most efficient heating? Why?
6. How does graphing the data help to determine the most efficient height for heating a
liquid in a beaker?