The rate law of a reaction, A-> B+C is given by the expression: Rate=k, where k=0.0113 mol/L min. If the initial concentration of the reactant is 0.225 mol/L, how long does it take for the concentration to decrease to 0.180 mol/L?
I know i have to find the order of the reaction to use the right integrated rate equation but how do i get the order of the reaction?
If rate = k, isn't that a zero order reaction?
Yes in fact it is. So does that mean that the time it takes for the concentration to decrease to 0.180 mol/l would just be k then since its a zero order?
To determine the order of the reaction, you can use the method of initial rates or the method of integrated rate equations.
Method of initial rates:
1. Perform a series of experiments with different initial concentrations of reactant A.
2. Keep the concentrations of reactants B and C constant.
3. Measure the initial rate of each experiment.
4. Compare the initial rates at different concentrations of reactant A.
5. If the initial rate changes significantly as the concentration of A changes, the reaction is likely not first order. You might need to try different potential orders (e.g. zero, first, second) until you find the one that matches the experimental data.
Method of integrated rate equations:
1. The integrated rate equation for a first-order reaction is given by: ln([A]t/[A]0) = -kt
where [A]t is the concentration of reactant A at time t, [A]0 is the initial concentration of reactant A, k is the rate constant, and t is time.
2. Rearrange the equation to isolate t: t = (-1/k) * ln([A]t/[A]0)
3. Calculate the values of t using the given concentration values and the rate constant, k.
4. If the obtained values of t show a linear relationship with ln([A]t/[A]0), then the reaction is likely first order. If not, you might need to try different potential orders until you find the one that matches the experimental data.
In this specific case, since the rate law is given as Rate = k, it implies that the reaction is independent of the concentration of the reactant A (zero order). Hence, the reaction is first order overall with respect to A.