Question

PROCESSING THE DATA

1. Was the reation zero, first, or second order. with respect to the concentration of crystal violet? Explain.
2. Calculate the rate constant, k, using the slope of the linear regression line for your linear curve (k = -slope for zero and first order and k = slope for second order). Be sure to include correct units for the rate constant. Note: This constant is sometimes referred to as the pseudo rate constant, because it does not take into account the effect of the other reactant, OH-.
3. Write the correct rate law expression for the reaction, in terms of crystal violet (omit OH-).
4. Using the printed data table, estimate the half-life of the reaction; select two points, one with an absorbance value that is about half of the other absorbance value. The time it takes the absorbance (or concentration) to be halved is known the half-life for the reaction. (As an alternative, you may choose to calculate the half-life from the rate constant, k, using the appropriate concentration-time formula.)

Answer 1

To determine the reaction order with respect to the concentration of crystal violet, compare the changes in initial reaction rates with the corresponding changes in initial concentrations. Use the slope of the linear regression line to calculate the rate constant. The rate law expression can be determined from the balanced chemical equation. The half-life of the reaction can be estimated using the absorbance values.

Step-by-step explanation:

To determine the reaction order with respect to the concentration of crystal violet, you can compare the changes in the initial reaction rates with the corresponding changes in the initial concentrations. If the initial reaction rate changes linearly with the concentration, the reaction is first order. If the initial reaction rate doubles when the concentration doubles, the reaction is second order. If the initial reaction rate remains constant regardless of the concentration, the reaction is zero order.

To calculate the rate constant, k, for the reaction, you can use the slope of the linear regression line for the linear curve. If the reaction is zero or first order, the rate constant, k, is equal to the negative slope. If the reaction is second order, the rate constant, k, is equal to the slope.

The rate law expression for the reaction in terms of crystal violet can be determined by looking at the balanced chemical equation. The rate law expression will include the concentration of crystal violet raised to an exponent that corresponds to the reaction order. For example, if the reaction is first order, the rate law expression will be rate = k * [crystal violet].

The half-life of a reaction can be estimated by selecting two points on the graph where the absorbance values are halved. The time it takes for the absorbance to be halved is known as the half-life. Alternatively, you can calculate the half-life from the rate constant using the appropriate concentration-time formula.