Chapter 13, Problem 72E

A mixture of gases A₂ and B₂ are introduced to a slender metal cylinder that has one end closed and the other fitted with a piston that makes a gas-tight seal so that the gases are a closed system. The cylinder is submerged in a large beaker of water whose temperature is 25 °C, and a spark is used to trigger a reaction in the cylinder. At the completion of the reaction, the piston hasmoved downward, and the temperature of the water bath has increased to 28 °C. If we define the system as the gases inside the cylinder, which of the following best describes the signs of q, w, and SE for this reaction?

1. q< 0, w< 0, ΔE< 0
2. q< 0, w> 0, ΔE< 0
3. q< 0, w> 0, the sign of ΔE cannot be determined from the information given
4. q>0, w>0, ΔE>0
5. q>0, w< 0, the sign ofΔE cannot be determined from the information given