The partial pressure of a compound A changes as follows: time 0 10 20 30 40 50min PA 4.00 2.94 2.32 1.92 1.64 1.42 Pa Make a graph of PA versus time. Use your graph to evaluate (i) the average reaction rate (in Pa min-1) over the first 40 minutes, and (ii) the instantaneous reaction rate (in Pa min-1) at time = 40 min.