Presentation on theme: "Air Bag Composition Air Bags require fast chemical reactions There are several important parts to the air bag Crash Sensors, and Propellant Air Bags use."— Presentation transcript:
Air Bag Composition Air Bags require fast chemical reactions There are several important parts to the air bag Crash Sensors, and Propellant Air Bags use the decomposition of Sodium Azide or NaN3 to inflate the bag
Explosives Explosives use the principle of turning a small volume of liquid or solid, into large volume of gas A shockwave is produced when an explosive is ignited due to the rapid expansion of gas
Nitrogen Nitrogen is used in many types of explosives, for example Dynamite (Nitroglycerine) It is very toxic, but it decomposes after being ignited It has low molar mass, the molecules reach a very high velocity Sodium Azide doesnt require other elements (Eg. Oxygen)
Sensor reads crash Propellant is heated/ignited Gas has no where to go but into the bag Bag inflates rapidly Bag begins to deflate as soon as blown up fully(Allowing for actual cushion) This all happens within 1/20 th of a second.Formula : 2 NaN3(s) 2 Na(l) + 3 N2(g)
Relating Air Bags To KMT 2) Particles move in rapid straight line motion. 5) At any given temperature, the average kinetic energy of the particles in all gases is the same. When the Nitrogen Azide is ignited it turns into a gas, and as it is being heated the kinetic energy increases greatly, and because particles move in rapid straight line motion they move out into the airbag.
Relating Air Bags to Charles' law Once the nitrogen azide is ignited its temperature is very hot and so it expands rapidly (chemical reaction produces heat), but as it expands it also cools down significantly from the outside air temperature. So the nitrogen gas takes up less volume and the bag deflates slightly allowing for it to actually act as a cushion instead of a wall.
Rockets Newtons third law of motion – For every action, there is an equal and opposite reaction
Newtons third law Must have low Molecular Mass Chemical reaction must be extremely fast Reaction must release a lot of heat
Common Propellants Used in Rockets The Space shuttle must contain gasoline (or diesel) and oxygen since there is no air to provide the other reactant. The chemists of space shuttle discovered that the shuttle uses liquid hydrogen and liquid oxygen in which they react together in a violent reaction to form water vapour with low molecular mass of 18.
Relating Rocket to KMT The first and third criteria in previous slide relate to the KMT of gases because both criteria state how, for example, If you take two balloons, fill one with Hydrogen Gas and one with Carbon Dioxide and find that the balloon filled with H 2 deflates faster than the balloon filled with CO 2
Relating Rockets to Gay – Lussacs law As the temperature of any gas is increased, the average kinetic energy increases. So the last criterion for a rocket fuel, the increases temperature, would also lead to an increase in molecular velocities.