ZAMBONI! $(22$ points$)$

At indoor ice$-$skating rinks, the resurfacing machine, known as a Zamboni, is typically powered by

means of an internal combustion engine that emits air pollutants into the rink building, including

carbon monoxide $($CO$).$ As we will learn more about later in the semester, CO is poisonous because

it binds to hemoglobin in your blood, reducing the amount of oxygen that can be delivered throughout

your body.

Let's model the rink as a CMFR$,$ with volume $V=20,000m^3$ and ventilation rate $Q=250m^{3}mi{n}^{-1}.$

Assume that the CO concentration in outdoor air is negligible. Also assume that the indoor

concentration is zero before the Zamboni begins operation, and the ambient air temperature is $15C.$

Consider the CO concentration that results from one operation cycle of the Zamboni. To resurface the

ice, the Zamboni operates for $15$ minutes and emits $100gmi{n}^{-1}$ of CO during operation.

$($a$)$ What is the peak CO concentration in the air in the rink during and after the single Zamboni

operation cycle? Give your answer in mole fraction. $(8$ points$)$

$($b$)$ Sketch the CO concentration in the rink air versus time for a $2-$hour period beginning with the

start of the resurfacing operation. Label the components of the graph using the same level of detail

that we did in class. $(8$ points$)$

$($c$)$ A skater exercises on the rink for $1$ hour beginning immediately after the resurfacing operation is

complete. What is the CO concentration at the end of that hour? Give your answer in mole

fraction. $(6$ points$)$