How to determine the order of a reaction?

Question

For a postlab, I have to graph the absorbance of a reaction between crystal violet and NaOH against time in sec, ln(absorbance) vs sec, and 1/abs vs sec. I'm supposed to be able to determine the order (0, 1, 2) of the reaction from looking at the three graphs. Do I look for which graph gives a positive slope?

Answer 1

In a zero order reaction if you plot [A] vs. time you get a straight line with a negative slope

In a first order reaction if you plot ln [A] vs. time you get a straight line with a negative slope

In a second order reaction if you plot 1/[A] vs time you get a straight line with a positive slope.