Airbags

The first thing you must know is that an airbag is deployed when the car decelerates very quickly, and a crash sensor releases a signal that initiates the inflation of the airbag.When the crash sensor senses the impact, its signal turns on an electrical circuit that ignites a pellet of NaN3, also known as sodium azide. This creates a reaction that produces hot nitrogen gas that fills the airbag. When the driver hits the airbag, though, the airbag has already begun deflating to create a cushion for the driver. Image

The gas laws are involved in different ways. How the airbag is inflated is due to Charles law, which states that volume and temperature are directly proportional when the pressure is constant. T1=The nitrogen gas that fills the airbag is extremely hot from the reaction, causing it to inflate; V1=Since the temperature is very hot the gas expands rapidly as well, filling the airbag; T2=While expanding, the gas cools down significantly from the temperature of the outside air; V2=The volume will decrease, deflating the bag slowly to create a cushion for impact. To solve for the amount of Nitrogen gas after inflation, you must now that when the reaction occurs the heat generated is 300 degrees Celsius or 573 K. Airbags are usually 60.0 L, the volume that the N2 fills into, and the temperature of the N2 returns to 25 degrees Celsius when the gas had fully inflated the airbag, and has begun to deflate. 

(V1)(T2)=(T1)(V2)

(60.0L)(298K)=(V)(573K)

(17880 L K)=(V)(573K)

V=31.20418 L

Airbags are essential in preventing many injuries from car accidents in our society.Airbags are continuously being developed, and perhaps in the future, scientists can create an airbag that will protect us during and after the crashes.

Sources

http://www.chemistry.wustl.edu/~edudev/LabTutorials/Airbags/airbags.html

http://www.lanl.gov/quarterly/q_sum03/airbags.shtml

Class Notes

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1 Comment

  1. Nice blog! I like how you included the equation for Charles’ Law. Make sure when you include equations, to write what the variables stand for. In this case, it’s self-explanatory, but it will help the lost reader 🙂

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