Discussion chemical Equilibria and kinetics Essay

916 Words Dec 14th, 2013 4 Pages
Discussion Our experiment is divided into 9 parts:
A. Effect of Nature of Reactants to the reaction rate.
B. Effect of Temperature to the reaction
C. Effect of Concentration to the Reaction Rate
D. Effect of Catalyst to the Reaction Rate
E. Chromate-Dichromate Equilibrium
F. Thiocyanatoiron (III) Complex Ion Equilibrium
G. Weak Acid Equilibrium (Ionization of Acetic Acid)
H. Weak Base Equilibrium Ionization of Ammonia
I. Saturated Salt (Sodium Chloride) Equilibrium
On part (A) we are to observe which reaction rate is faster, and doing the experiment. We have concluded that:
“Aluminum had faster rate of reaction rate than iron because it is more active than iron based on the activity series.”
TABLE B.
Temperature (C)
Time
…show more content…
In (i), a reaction vessel starts out with 100% A, and it begins to undergo conversion to B. At very early times (leftmost region of the graph, shaded pink), only a negligible amount of B is present, so the observed rate is that corresponding to the forward reaction, A → B. As B begins to accumulate (middle portion of graph, lavender), some of it undergoes the reverse reaction, B → A. The net rate still favors production of B, so that the concentration of B continues to rise and [A] still drops, but more slowly. The conversion from A to B is still faster than the conversion of B to A, and this is indicated in the figure by the relative length of the arrows in the chemical equation. Finally, enough B is present so that the forward and reverse reaction rates are in balance, and the net rate is zero (right side of graph, purple). These equilibrium conditions, once attained, persist indefinitely.

If the starting conditions are 100% B, as in (ii), the kinetics at very early times (leftmost region of the graph) are dominated by the reverse reaction, B → A. Once some A forms, the rate of the forward reaction begins to pick up. The net rate still favors production of A for a short time (middle graph), but its concentration levels off by ~60 s, having attained equilibrium level. Notably, these equilibrium conditions are the same as those in (i) - this assumes both experiments are carried out at the same temperature.

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