In this experiment, a simple airbag will be constructed which will inflate on an impact. The bag will be made of thin plastic. A chemical reaction will be used to inflate the airbag.
HYPOTHESIS:
Reaction of an acid with a carbonate salt should liberate enough gas, in a closed bag, to make an airbag.
VARIABLES:
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Independent variables – Quantity of reactants used.
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Dependent variables – The amount of gas released to fill the pouch.
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Controlled variables – Temperature and pressure.
REQUIREMENTS:
- Dilute HCl
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Hydrogen bicarbonate salt (H2CO3)
APPARATUS:
- Measuring cylinder
- Analytical balance
- Plastic zip-pouch
- Test tube
- Rubber cork
- Small beaker
PROCEDURE:
The airbag is made in a manner that the gas is released only when there is an impact. The impact leads to the inflation of the airbag. The airbag is made according to the following method:
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Measure 200.0 cm3 of dilute HCl with a measuring cylinder and pour it into the plastic zip-pouch.
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Weigh 8.0 grams of H2CO3 with an analytical balance.
- Divide the weighed salt into two equal parts and add it into two test tubes. Cork the test tubes with rubber corks.
- Add the test tube into the zip-pouch.
When the airbag is ready, an impact has to be applied on the airbag. The impact will shatter the test tubes and the dilute acid present will react with the carbonate salt to give out gas.
DATA COLLECTION:
Least counts:
Measuring cylinder = 0.20 cm3
Analytical balance = 0.01 g
Colour:
HCl solution = Colourless
Hydrogen bicarbonate salt = White (amorphous)
DATA ANALYSIS:
H2CO3 (s) + HCl(aq) → H2O + CO2 + HCl
The above reaction is the reaction that occurs in the airbag. The airbag inflates into a tight plastic bag soon after the impact. Due to a large amount of acid and salt present in the bag, there is spontaneous reaction and a lot of carbon dioxide gas is released.
As the reaction proceeds the amount of carbon dioxide formed decreases.
CONCLUSION & EVALUATION:
The airbag was effectively constructed. The reactants produced enough carbon dioxide to totally inflate the pouch. Concentrated HCl was not used as it would have reacted with the plastic bag and the contents would have spilled out of the pouch. There also could have been small leakages which may have increased the time taken for the pouch to inflate. Although the experiment was easy to follow, the amount of time taken for the bag to inflate is not appropriate enough for an accident. Hence, a more effective method should be used, in which the amount of time taken for the reactants to produce the gas reduces (like reactions between Mg and dilute HCl). Airbags have various applications in everyday life and play an important part in today’s world. Some of these applications are listed below:
- It is used to protect the occupants of a car, motorcycle, etc. in an accident
- It is used as a cushion for landing of various space exploration machines, like Mars Pathfinder.
- It is used to cushion the landing of objects from heights.
- It reduces the injuries sustained to an automobile driver.
