Integrated Rate Law for 2nd Order Reactions

[samy4408]

hello i have a question about kinetics : to have the integrated rate law for second order reaction the professor write the following

why we don't write the rate like this : rate = -1/2(d[1]/dt) ?
why we ignore the stoichiometric coefficient ?

 

[Borek]

Rate is defined as a speed of change of the concentration, period.

 

[mjc123]

"Rate of reaction" is often defined as (1/a)*d[A]/dt, where a is the stoichiometric coefficient of A (negative for reactants, positive for products). Then it's the same whichever reagent you look at, but it depends how you write the equation, e.g. it would be different for A → ½B or 4A → 2B. My preference is always to talk in terms of the rate of change of concentration of a specified reagent.