Summer Research Program for Science Teachers

Robert Nociti

George Washington H.S.

How can we calculate the molecular weight of butane?

[9-12 Content Standard B- Structure and properties of matter]

Materials:

Apron and goggles

Volumetric flask (1 L)

Stopper / cardboard square from milk container

Water displacement trough / deep plastic basin

Butane lighter (striker removed)

Electronic balance

Q - tips and paper towels

Periodic table [Teaching Standard D- Make accessible science tools]

Procedure:

1. Weigh lighter and record in the space provided

2. Fill trough and flask with water

3. Stopper flask and invert into trough

4. Remove stopper and maintain neck of flask underwater

5. Have partner place lighter underwater and fill flask to 1L mark

6. Stopper flask and remove from trough

7. Carefully dry lighter and reweigh

8. Place flask into fume hood and remove stopper to allow venting

Questions:

1. What is the weight of your lighter? ______________

2. What is the weight after step 5? -______________

3. What is the weight of 1 Liter of butane? = ______________

4. What would 1 mole of butane weigh? (22.4L) ______________ [Content Standard Unifying Concepts- Change, constancy, and measurement]

5. Calculate the formula weight of butane (C₄H₁₀) ______________

6. Calculate your percent error ______________

100% - (Formula weight/calculated mole weight) X 100%

7. How well do your results compare with the rest of the class?