Dimensions of chemical reaction rates

2.1.3.P16

 

The concentration of a chemical, A, is often written a "[A]". Since we are using square brackets to tell us to do a dimensional analysis, we will instead use the notation "c_A" to represent the concentration of a chemical A. We express dimensionality to show how different measurements must be combined to create the quantity involved:  in powers of M (measured by a scale), L (measured by a ruler), and T (measured by a clock).The dimensionality of a concentration is number/unit volume, [c] = 1/L³. 

 

1. If the chemical reaction

 

 

has rate constants k_f for the forward reaction and k_r for the reverse reaction, then (in the absence of a catalyst) the rate of change of the concentration of the chemical AB is given by

 

 

If this is so, are the dimensionalities of k_f and k_r the same?

• Yes
• No
• Cannot tell from the information given. 

 

Explain the reasoning you used to make your decision. 

 

2. What is the dimensionality of the rate constant k_f ?

 

 

Joe Redish 10/21/16