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The accelerometer keeps track of how quickly the speed of your vehicle is changing. When your car hits another car—or wall or telephone pole or deer—the accelerometer triggers the circuit. The circuit then sends an electrical current through the heating element, which is kind of like the ones in your toaster, except it heats up a whole lot quicker. This ignites the charge which prompts a decomposition reaction that fills the deflated nylon airbag (packed in your steering column, dashboard or car door) at about 200 miles per hour. The whole process takes a mere 1/25 of a second. The bag itself has tiny holes that begin releasing the gas as soon as it’s filled. The goal is for the bag to be deflating by time your head hits it. That way it absorbs the impact, rather than your head bouncing back off the fully inflated airbag and causing you the sort of whiplash that could break your neck. Sometimes a puff of white powder comes out of the bag. That’s cornstarch or talcum powder to keep the bag supple while it’s in storage. (Just like a rubberband that dries out and cracks with age, airbags can do the same thing.) Most airbags today have silicone coatings, which makes this unnecessary. Advanced airbags are multistage devices capable of adjusting inflation speed and pressure according to the size of the occupant requiring protection. Those determinations are made from information provided by seat-position and occupant-mass sensors. The SDM also knows whether a belt or child restraint is in use.



Today, manufacturers want to make sure that what’s occurring is in fact an accident and not, say, an impact with a pothole or a curb. Accidental airbag deployments would, after all, attract trial lawyers in wholesale lots. So if you want to know exactly what the deployment algorithm stored in the SDM is, just do what GM has done: Crash thousands of cars and study thousands of accidents. The Detonation: Decomposition Reactions Manufacturers use different chemical stews to fill their airbags. A solid chemical mix is held in what is basically a small tray within the steering column. When the mechanism is triggered, an electric charge heats up a small filament to ignite the chemicals and—BLAMMO!—a rapid reaction produces a lot of nitrogen gas. Think of it as supersonic Jiffy Pop, with the kernels as the propellant. This type of chemical reaction is called “decomposition”. A decomposition reaction is a reaction in which a compound breaks down into two or more simpler substances. A reaction is also considered to be decomposition even when one or more of the products are still compounds.



Equation 1. general form of decomposition equations When sodium azide (NaN3) decomposes, it generates solid sodium and nitrogen gas, making it a great way to inflate something as the small volume of solid turns into a large volume of gas. The decomposition of sodium azide results in sodium metal which is highly reactive and potentially explosive. For this reason, most airbags also contain potassium nitrate and silicon dioxide which react with sodium metal to convert it to harmless compounds. Equation 2. decomposition of sodium azide Ammonium nitrate (NH4NO3), though most commonly used in fertilizers, could also naturally decompose into gas if it’s heated enough, making it a non-toxic option as an airbag ingredient. Compared to the sodium axide standard, half the amount of solid starting material is required to produce the same three total moles of gas, though that total is comprised of two types, dinitrogen monoxide (N2O) and water vapor (H2O). Equation 3. decomposition of ammonium nitrate Highly explosive compounds like nitroglycerin (C3H5N3O9) are effective in construction, demolition, and mining applications, in part, because the products of decomposition are also environmentally safe and nontoxic. However, they are too shock-sensitive for airbag applications. Even a little bit of friction can cause nitroglycerin to explode, making it difficult to control. The explosive nature of this chemical is attributed to its predictable decomposition which results in nearly five times the number of moles of gas from only four moles of liquid starting material when compared to both sodium azide and ammonium nitrate alternatives.





You're are NOT answering this: Scientific question: How does the choice of chemical ingredient ia airbn ag influence their effectiveness.

As you talks about the dimensional analysis setup, stock and explain each part using da ts format he article.


Point directly to the collected data as evidence. Since the scientific question relates the chemical ingredients to effectiveness, you might consider discussing all the outcomes for each chemical ingredient (time, volume, popped/not inflated, enough/inflated perfectly, amount initially used separately.

Answer 1

The choice of chemical ingredients in airbags influences their effectiveness in several ways:

Time: Sodium azide ignites faster than ammonium nitrate, decomposing in under 1/25 sec vs. requiring heating to ignite. Sodium azide's faster ignition leads to quicker airbag inflation.

Volume: Sodium azide produces 3 moles of gas from 2 moles of solid, while ammonium nitrate produces 3 moles of gas from 4 moles of solid to achieve the same total moles of gas. Less starting material is needed for sodium azide to produce the same volume of gas.

Amount used: To produce the same volume of gas, half the amount of solid sodium azide (2 moles) is required compared to ammonium nitrate (4 moles). Less ingredient is needed for sodium azide.

Popped/Not inflated: Highly explosive compounds like nitroglycerin are too shock-sensitive and difficult to control, easily popping the airbag before it fully inflates. Sodium azide and ammonium nitrate can be controlled to properly inflate the airbag.

Enough/Inflated perfectly: Advanced airbags with sensors can determine the optimal amount of each chemical to inflate based on occupant size. Multiple stages of inflation are possible for perfect inflation control and cushioning. Single-stage less controlled explosions may over- or under-inflate the airbag.

Data:

Equation 1: General decomposition equation

Equation 2: Decomposition of sodium azide

Equation 3: Decomposition of ammonium nitrate

Sodium azide → 3 moles gas / 2 moles solid

Ammonium nitrate → 3 moles gas / 4 moles solid

Nitroglycerin → 5 moles gas / 4 moles liquid

In summary, the choice of chemical impacts how quickly, how much, and how controllably the airbag inflates. Sodium azide and ammonium nitrate can be optimized and controlled, while nitroglycerin is too volatile. Less material is needed for faster-acting sodium azide. Advanced sensors enable perfectly inflating multistage airbags regardless of the chemical mixture. The data and equations show the mole ratios for each chemical decomposition.

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