Chemistry

Problem

A research team measures the rate of the reaction

\mathrm{D} + \mathrm{E} \rightarrow \text{products}

(30\,^{\circ}\text{C})

a total of five times. Two trials are intended as replicates to assess reliability. The initial-rate results are collected in the table.

Trial	$[\mathrm{D}]_0\,(\text{M})$	$[\mathrm{E}]_0\,(\text{M})$	Initial rate $(\text{M}\,\text{s}^{-1})$
1	0.10	0.10	$2.50 \times 10^{-5}$
2	0.20	0.10	$9.80 \times 10^{-5}$
3	0.10	0.20	$5.10 \times 10^{-5}$
4	0.20	0.20	$2.10 \times 10^{-4}$
5	0.10	0.10	$3.80 \times 10^{-5}$

Assume a rate expression of the form

\text{rate} = k[\mathrm{D}]^r[\mathrm{E}]^s

. (a) Using the data, determine the reaction order with respect to D and to E. Clearly indicate which trials you select for each comparison and justify how you dealt with the discrepancy between Trials 1 and 5. (b) Compute the numerical value and appropriate units of the rate constant

k

, using an average initial rate for the duplicated concentration set. (c) Propose two plausible experimental sources of error that could account for the difference between Trials 1 and 5, and explain how each source would influence the measured initial rate. (d) Predict the initial rate for a new experiment conducted with

[\mathrm{D}]_0 = 0.15\,\text{M}

and

[\mathrm{E}]_0 = 0.30\,\text{M}

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