The Bunsen Burner

Background Information:

Bunsen burners are often used in lab to heat materials. The burner functions by the combustion of a mixture of air and gas. The amount of air and gas used can and needs to be controlled for the burner to function properly. In this lab, you will learn the parts of the Bunsen burner and their functions. You will also learn how to best use the burner in future laboratory experiments.

Safety Precautions: Closed-toed shoes, safety goggles, and lab aprons must be worn during this lab. Glassware will be hot. Use precaution when working with an open flame. (Tie back hair if it is long.)

Materials:
Bunsen burner2- 250 mL beakers50 mL graduated cylinder
2 Ring stands2-Wire gauzeStriker
Iron ringBeaker tongsRuler

Procedure:

  1. Examine your burner before you connect it to the gas outlet. Look at Figure 1 below and locate the parts listed on the burner at your lab station.

Figure 1

  1. When finished, connect the rubber tube to the gas outlet. Be sure to remove all flammable materials from your lab station.
  2. Adjust the air intake valve until it is half-open. Have your striker on hand and slowly turn on the gas valve at your station until it is fully open. Hold the striker over the burner and strike it until your burner lights. If after 2 or 3 tries the burner has not lit, turn off the gas valve clear the air and try again.
  3. Turn off the burner by turning off the gas valve
  4. Have each group member practice lighting the Bunsen burner. Adjust the air intake so that the flame is blue and a pale blue inner cone is visible. Put out the flame.
  5. Arrange your ring stand, iron ring, wire gauze and Bunsen burner as shown below. Light the burner. Do not put the beaker on yet.

  1. Adjust the iron ring so that it is 2 cm above the base of the Bunsen burner. Move the Bunsen burner to the opposite side of the ring stand. Place a second iron ring so that it is 6 cm above the base of the Bunsen Burner. Light burner.
  2. Add 50 mL of water to one 250 mL beaker. Place the beaker on the wire mesh. Note what time you put the beaker on the flame. Record how long it takes for the water to boil. Use tongs to remove the beaker.
  3. Fill a second 250 mL beaker with 50 mL of water. Place this beaker on the second iron ring with wire mesh.Move the burner under this beaker. Note what time you put the beaker on the flame. Record how long it takes for the water to boil.
  4. Use beaker tongs to remove the beaker. Empty the water into the sink and place the beaker on a towel to cool. (Allow to cool for at least 3 minutes.)
  5. Clean up your station.

Data Table:

Height above burner (cm) / Time it takes to boil (sec)
2
6

Questions:

  1. What would happen if the air intake opening was made very small?
  1. If the burner did not light after opening the gas valve, what might be wrong?
  1. Based on your data, where is the hottest part of the flame?
  1. At what height does the water boil the quickest according to your data?
  1. Why was it important to make sure the starting water volume was the same?
  1. Why did you need to use two separate beakers, iron rings, and wire meshes?