which statement is correct?

Question

Gasoline is injected into the cylinder of a car’s engine and compressed on the upstroke of the piston. The compression is well modeled as adiabatic. At the moment when the cylinder’s volume is at its lowest, but before the sparkplug ignites the mixture,
A. The ideal gas law applies, but will not apply after the ignition because it does not account for reactions such as combustion.
B. The temperature of the gas is higher than it was before the compression started.
C. You cannot plausibly write an energy balance using“the gas inside the cylinder” as a system, because of the very complex physical shape of the spark plug.
D. If a cubic equation of state describing the fluid at this point yields only one real number solution, this is an indication that the pressure of the gas is above the critical pressure.
E. None of these are correct.

Answer 1

A. Incorrect. During the compression phase it is unlikely the ideal gas law will be accurate because of the high pressures. After the reaction the pressure will be even higher. (No equation of state explicitly “accounts” for a reaction, only the relationships between P-V-T.)
B. Correct.The work added during the compression process would increase the temperature of the gas.
C. Incorrect. You can define “the gas inside the cylinder” as a system and write an energy balance even if you don’t know exactly what the shape of the cylinder is.
D. Incorrect. A cubic EOS yields only one real solution for pressure above the critical temperature, and this is true whether the pressure is above or below the critical pressure.
E. Incorrect. One statement is true.