Introduction

Throughout this semester we have provided experiments that illustrate some of the more complex concepts of chemistry as you were learning about them in lecture. We have also presented you with evidence that each of the concepts or techniques covered was either valuable to your future as a chemist or relevant to your everyday life.  This experiment on ‘Gas Laws and Airbags’ is both. Gas laws and the general concepts of gas volumes and pressures are vital for anyone deciding on a career in chemistry and even more important to those focusing on medicine. For example, oxygen saturation in the body is controlled by both internal and external pressures. Why is it harder to breathe at higher altitudes? What is hypoxia? What happens to a patient who receives too much oxygen? Not enough? And how do you as the doctor or nurse control the volume delivered? None of these questions can be answered without a firm understanding of the gas laws.

The experiment you will conduct today will not require you to administer oxygen to a patient (hopefully) but rather focuses on the automobile airbag, another very useful device that depends on the use of gas laws. Airbag deployment is chemically created because mechanical deployment would be too slow. An explosive production of nitrogen gas from sodium azide creates the filled airbag in a fraction of a second. Gas laws allow the construction of a completely full but not overfull bag of gas that keeps the driver and passenger(s) of a car from serious injury during a collision.

In order to study how gas laws can provide answers to the construction of airbags, you are going to design and build one.  In addition to constructing the airbag, we are also going to revisit the use of a barometer to measure the atmospheric pressure. Some barometers use a Vernier scale, so make sure you remember how to read this type of scale (See Experiment 2: A Submarine Adventure for a refresher).