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Chapter 5: Problem 99

The air bags that provide protection in automobiles in the event of an accident expand because of a rapid chemical reaction. From the viewpoint of the chemical reactants as the system, what do you expect for the signs of \(q\) and \(w\) in this process?

Short Answer

Expert verified
In the rapid chemical reaction that causes the airbags to expand, heat is released from the system (chemical reactants) to the surroundings (airbags), resulting in a positive sign for the heat transfer (q). Additionally, work is done by the system on the surroundings as the gas produced exerts pressure on the airbags to expand, leading to a positive sign for the work done (w). Therefore, the expected signs are: \(q > 0\) and \(w > 0\).

Step by step solution

01

The Sign of Heat Transfer (q)

During the rapid chemical reaction in the airbags, gas is produced that causes the airbags to inflate. The conversion of reactants into products usually releases energy in the form of heat (exothermic reaction). Therefore, we expect a positive sign for "q" as heat is being transferred from the system (chemical reactants) to the surroundings (the airbags).
02

The Sign of Work Done (w)

When the airbags expand, the gas produced during the reaction exerts pressure on the surroundings (the airbags' interior). This means that the gas expansion causes work to be done on the surroundings as the pressure is applied from within the system, pushing the airbags to expand. In this case, the sign of "w" will be positive, as work is done by the system (chemical reactants) to the surroundings (airbags). #Summary# In conclusion, for the rapid chemical reaction that occurs in the automobile airbags during an accident, the expected signs are: 1. Heat Transfer (q): Positive 2. Work Done (w): Positive

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Most popular questions from this chapter

A sample of a hydrocarbon is combusted completely in \(\mathrm{O}_{2}(g)\) to produce $21.83 \mathrm{~g} \mathrm{CO}_{2}(g), 4.47 \mathrm{~g} \mathrm{H}_{2} \mathrm{O}(g),\( and \)311 \mathrm{~kJ}$ of heat. (a) What is the mass of the hydrocarbon sample that was combusted? (b) What is the empirical formula of the hydrocarbon? (c) Calculate the value of \(\Delta H_{f}^{\circ}\) per empiricalformula unit of the hydrocarbon. (d) Do you think that the hydrocarbon is one of those listed in Appendix C? Explain your answer.

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