(A) For a first order reaction, the rate law is given by the equation: rate = k[A], where k is the rate constant and [A] is the concentration of the reactant.
Given:
Rate constant (k) = 2.5 * 10^-6 s^-1
Initial concentration ([A]) = 1.0 moldm^-3
To find the initial rate, substitute the given values into the rate law equation:
Rate = k[A]
Rate = (2.5 * 10^-6 s^-1) * (1.0 moldm^-3)
Rate = 2.5 * 10^-6 moldm^-3s^-1
Therefore, the initial rate is 2.5 * 10^-6 moldm^-3s^-1.
(B) For a second order reaction, the rate law is given by the equation: rate = k[A]^2, where k is the rate constant and [A] is the concentration of the reactant.
Given:
Initial rate = 5.0 * 10^-7 moldm^-3s^-1
Initial concentration ([A]) = 0.2 moldm^-3
To find the rate constant, rearrange the rate law equation to solve for k:
Rate = k[A]^2
k = Rate / [A]^2
k = (5.0 * 10^-7 moldm^-3s^-1) / (0.2 moldm^-3)^2
k = (5.0 * 10^-7 moldm^-3s^-1) / 0.04 moldm^-6
k = 1.25 * 10^-5 s^-1
Therefore, the rate constant is 1.25 * 10^-5 dm^3mol^-1s^-1.
1 (A). The rate constant of a first order reaction is 2.5 * 10^-6s^-1 and the initial concentration is 1.0 moldm^-3. What is the initial rate in moldm^-3s^-1.
(B). The initial rate of a second order reaction is 5.0 * 10^-7 moldm^-3s^-1 and the initial concentration of the two reacting substances are each 0.2 moldm^-3. What is the rate constant in dm^3mol^-1s^-1?
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