The ideal gas equation
Edit Date: 2016-10-08 11:34:31
Question:

The simple gas laws describe the relationships involving the pressure, volume, temperature, and amount of an ideal gas.

• Boyle’s law states that for a fixed amount of gas at a constant temperature, the gas volume is inversely proportional to the gas pressure. $V\propto \frac{1}{p}$
• Avogadro’s law states that the volume of a gas is proportional to the amount of the gas (at constant temperature and pressure. $V\propto n$
• Charles law (also called Charles-Gay Lussac’s law) states that the volume of a fixed amount of gas at constant pressure is directly proportional to its temperature (in Kelvin).$V\propto T$

The combination of these three laws is: $V\propto \frac{nT}{P}$

This law can be rearranged to:$PV\propto nT$

The proportional relationship can be written as equation: $PV = nRT$ , where R is a proportional constant termed the gas constant.  The value of R (in SI unit) is:

$R = 8.3145Jmol^{-1}K^{-1}$

One well known characteristic of gases in that the expand to fill their containers and assume the shape of their containers.  A practical application of these characteristics is the reaction that forms N2(g)  in an automobile air-bag safety system. This reaction utilizes the rapid decomposition of sodium azide.

$2NaN_{3}(s)\overset{\Delta }{\rightarrow}2Na(1) + 3N_{2}(g)$

Simulation

Here is a simulation that simulates gas behavior:

The essential components of the system are an ignition device and a pellet containing sodium azide.  When activated, the system inflates and air bag in a very short time (milliseconds range).  Note: the liquid sodium is converted to harmless solid sodium due to special additives that are also present initially.

Picture credit:

http://auto.howstuffworks.com/car-driving-safety/safety-regulatory-devices/airbag1.htm

Question:

Which statement regarding the above chemical reaction is true: