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For the reaction 2A + B + 2C ? D + E the following initial rate data was collected at constant temperature. Determine the correct rate law for this reaction. All units are arbitrary.

Trial [A] [B] [C] Rate
1.0.225 0.150 0.350 0.0217
2.0.320 0.150 0.350 0.0439
3.0.225 0.250 0.350 0.0362
4.0.225 0.150 0.600 0.01270
A.Rate = k [A][B]^2[C]^-1
B.Rate = k [A]^2[B][C]
C.Rate = k [A]^2[B][C]^-1
D. Rate = k [A][B][C]
E.none of these choices is correct

User Aximili
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1 Answer

6 votes

Final answer:

From the given data, the correct rate law cannot be determined because none of the provided choices match the observed data exactly. The rate appears to be first order with respect to A, but additional experimentation is required to accurately determine the orders for B and C. E.none of these choices is correct

Step-by-step explanation:

To determine the correct rate law for the given reaction 2A + B + 2C → D + E, we need to analyze how changes in the concentrations of reactants affect the reaction rate.

Comparing trial 1 and trial 2, the concentration of A increases while B and C remain constant. The rate increases from 0.0217 to 0.0439 units. This implies that as the concentration of A increases, the rate increases proportionally, suggesting that the reaction is first order with respect to A.

Comparing trial 1 and trial 3, the concentration of B increases while A and C remain constant. The rate increases from 0.0217 to 0.0362 units, which is not a direct proportion to the increase in B. Thus, this comparison is not enough to conclude the order with respect to B.

Finally, comparing trial 1 and trial 4, the concentration of C doubles, while that of A and B remains constant. However, the rate decreases, indicating that the rate is inversely proportional to the concentration of C, or that the reaction may have negative order with respect to C.

As none of the provided rate law options ([A][B]^2[C]^-1, [A]^2[B][C], [A]^2[B][C]^-1, [A][B][C]) match the experimental observations perfectly, option E: 'none of these choices is correct' may be the best choice based on the given data. The proper rate law should be determined by further experimentation with isolated variations in concentrations.

User Vland
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