Consider the following hypothetical reaction: X(g) -----> Y(g) A 200.0-mL flask is filled with 0.120 moles of X. The disappearance of X is monitored at timed intervals. Assume that temperature and volume are kept constant. The data obtained are shown in the table below. Time (min) 0 20 40 60 80 moles of X 0.120 0.103 0.085 0.071 0.066 (b) Calculate the average disappearance of X in M/s in the first two 20-minute intervals. (c) What is the average rate of appearance of Y between the 20- and 60-minute intervals?