Physics I / Reaction rates and collision reasoning
Practice question · Fill in the blanks

Complete the statement with the correct term.

For a first-order reaction A → products, the rate law is rate = k·[A]ⁿ. The exponent n equals ______.

Word bank: 0 · 2 · 1 · 3

Hints
  1. The order is the exponent on concentration in the rate law.
  2. For this order the half-life does not depend on the starting amount.
Show the answer

For a first-order reaction A → products, the rate law is rate = k·[A]ⁿ. The exponent n equals 1.

Why

First-order means rate ∝ [A]¹. The exponent (reaction order) is 1, and the half-life t1t_{1}/₂ = ln(2)\ln(2)/k is independent of concentration.

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