4 posts • Page 1 of 1
I am confused as to the meaning of n and m concerning the overall reaction order. In lecture, we used an examples with NH4+ and NO2-, and we determined that rate 2/rate 1 = 2 = 2.0^m, therefore m is 1. I don't know where the 2.0 value came from, or how to determine n.
n and m are the variables used to represent the order of the individual reactants. Essentially, you could use any variables to represent the same thing but n and m are most commonly used. The overall order of the reaction is found by adding all of the orders of the individual reactants, so if there were only two reactants then the overall order would be n+m. The value of 2.0 comes from using the experimental data given in the problem. You set the ratio of the concentrations of two trials in the data raised to the power n (or m or whatever variable you use) equal to the ratio of the rate for each of the two trials. In the example you gave, both ratios were equal to 2 so the value of n would be 1 and the reactant would be first order.
When given an experiment table, you choose the two experiments in which one concentration is the same and one is changing. In this case, the concentration of one of the reactants is double so we divide the rates on one side and set it equal to the concentrations divided by each other, which is 2.0, to the power of m. the value of m is determined by seeing what it needs to be so that both sides are equal.
Who is online
Users browsing this forum: No registered users and 2 guests