LAB: Finding the Molar Mass of Butane
Materials:
• Volumetric Flask 500.0 mL
• Plastic bucket
• Butane lighter
• Electronic balance
• (Optional – Compressed air)
Procedure:
1. Read this procedure and construct a data table that will accommodate the data you will
collect. Use a spread sheet program to produce the data table.
2. Find the mass of the butane lighter
3. Fill the bucket 2/3 full of warm tap water
4. Drop lighter into water and wait 5 min for it to equalize in temperature
5. During this 5 minute wait, obtain the 500.0 mL volumetric flask, fill it with water at the same
temperature as that in the bucket, measure and record the temperature of the water.
6. Stopper the flask and invert into bucket.
7. Remove the stopper and keep the opening of the flask under water.
8. Depress the lever of the lighter and allow the butane gas to bubble up into the flask.
9. BE PATIENT! THIS WILL TAKE AT LEAST SEVERAL MINUTES. You may need to take
turns with your partner holding the lighter and flask.
10. Fill the flask to the 500.0 mL mark.
11. Stopper the flask and remove it from the bucket.
12. Place the flask into the fume hood and remove the stopper to allow it to vent the butane
(butane is flammable of course).
13. Carefully and
thoroughly dry the lighter and find it’s mass again. If compressed air is
available, a stream of high velocity air will aid in removing the water from the small crevices
of the lighter.
14. Determine the following values:
• Barometric pressure of the air in the room (internet weather info or weather channel)
• Vapor pressure of water at the temperature you measured (table provided).
