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For the reaction A + B → products, the following observations are made:
(1) If only the initial concentration of A is doubled, the reaction rate becomes twice its original value.
(2) If the initial concentrations of both A and B are doubled together, the reaction rate increases by a factor of 8.
The rate law for this reaction is:
- rate = k [A][B]²
- rate = k [A]² [B]²
- rate = k [A][B]
- rate = k [A]² [B]
Correct answer: rate = k [A][B]²
Solution
Doubling A -> 2x means order in A = 1. Doubling both -> 8x means 2^(1+b)=8, so b=2. Rate = k[A][B]^2.
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