The data below has been taken for the reaction of a dye with the hydroxide ion. The reaction was performed at two different hydroxide ion concentrations while the dye concentration was kept constant. What is the rate law?
[OH─] = 0.10 M [OH─] = 0.20 M
t (min) Abs ln(Abs) Abs ln(Abs)
0 1.000 0.000 1.000 0.000
1 0.905 -0.100 0.678 -0.389
2 0.811 -0.209 0.451 -0.796
3 0.735 -0.308 0.288 -1.245
4 0.664 -0.409 0.185 -1.687
I don't even know when to start. Can Someone do generic steps for a problem like this so i can understand how to do them?
Sure! Here are the general steps you can follow to determine the rate law from this set of data:
1. Understand the general form of the rate law: The rate law describes the relationship between the concentration of reactants and the rate of reaction. It is usually expressed in the form of rate = k[A]^m[B]^n, where [A] and [B] represent the concentrations of reactants, k is the rate constant, and m and n are the reaction orders with respect to A and B, respectively.
2. Determine the overall reaction order (m + n): To do this, you can compare the initial rate of reaction for the two different hydroxide ion concentrations at time 0. If the rate doubles when the concentration of reactant doubles, the reaction is first order with respect to the reactant. If the rate quadruples, the reaction is second order, and so on.
3. Calculate the reaction rate for each set of data: The data table provides the absorbance (abs) values and natural logarithm of absorbance (ln(Abs)) at different time intervals. To calculate the reaction rate, you need to calculate the change in absorbance with respect to time (ΔAbs/Δt) for each set of data points.
4. Calculate the initial rate of the reaction: The initial rate can be determined by taking the slope of the tangent line to the curve at t = 0. To do this, you can estimate the slope by calculating the change in ln(Abs) divided by the change in time (∆ln(Abs)/∆t) for the points closest to t = 0.
5. Determine the reaction order for each reactant: Once you have the initial rate, you can compare the initial rates for different concentrations of the hydroxide ion. If the rate of reaction changes as the concentration of the hydroxide ion changes, you can determine the order of the reaction with respect to the hydroxide ion.
6. Write the rate law: Using the determined reaction orders for each reactant, you can express the rate law for the reaction. For example, if the reaction is first order with respect to hydroxide ion ([OH^-]) and zero order with respect to the dye concentration, the rate law would be rate = k[OH^-]^1 (since anything raised to the power of 0 is equal to 1).
By following these steps, you should be able to determine the rate law for this reaction based on the provided data.