A reaction in aqueous solution follows the stoichiometry
X + 2 Y → 3 Z
The concentration of X is monitored over time and the following data are obtained:
Time (s): 0 25
[X] (M): 0.100 0.085
(a) Calculate the average rate of disappearance of X, in M⋅s−1, for the interval 0 s → 25 s.
(b) Determine the average rate of appearance of Z over the same time interval.
(c) Derive an algebraic expression that relates the rate of change of [Y] to the rate of change of [X] for this reaction. Then calculate the average rate of change of [Y] during the 0 s → 25 s interval.
(d) Using your results, calculate the average rate of change of the total molar concentration, [X] + [Y] + [Z], over the interval. State whether the total molar concentration increases, decreases, or remains constant, and justify your conclusion based on stoichiometry.