## 15.13 part a?

$aR \to bP, Rate = -\frac{1}{a} \frac{d[R]}{dt} = \frac{1}{b}\frac{d[P]}{dt}$

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### 15.13 part a?

So since the formation of HI is second- order wouldn't the formula for finding the rate = k x concentration^2?
The solutions says " From the units of the rate constant, it follows that the reaction is second-order; therefore, rate= k [H2] [I]

Isita Tripathi 2E
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### Re: 15.13 part a?

They're probably referring to the overall order of the reaction. Since there are two reactants, and each is first order, the overall order = 1+1 = 2.
The rate constant's units depend on the overall order.

skalvakota2H
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### Re: 15.13 part a?

Note that the equation for the formation of HI is given by: H2 + I2 → 2 HI
Since the question gives that each reactant is to the first order, this means that the total order, given by the sum of individual orders for each reactant, is 1+1, or 2.
A reaction need not be dependent on only one reactant concentration. Two different reactants can be combined in an elementary step, such as this, and still yield a second order reaction, since the reaction order is the total order.

Angel Ni 2K
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### Re: 15.13 part a?

The rate equals k(concentration of H2)(concentration of I2). It is, in a way, k(concentration)^2.