### Differential vs Integrated

Posted:

**Mon Mar 05, 2018 8:26 pm**I have a general question as to when to know to use the differential or integrated equations for first, second, or zero order.

Thanks.

Thanks.

Created by Dr. Laurence Lavelle

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https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=149&t=29016

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Posted: **Mon Mar 05, 2018 8:26 pm**

I have a general question as to when to know to use the differential or integrated equations for first, second, or zero order.

Thanks.

Thanks.

Posted: **Mon Mar 05, 2018 8:35 pm**

Usually the question tells you if a reaction is first, second, or zero order, but if you need to calculate it you can by comparing the rates of separate equations and how reactant concentrations change with them.

You use the differential rate law when determining a rate of an equation (either a general rate or a rate at a specific time (t)) and the integrated rate law for finding a specific concentration and deriving the half-life formula.

You use the differential rate law when determining a rate of an equation (either a general rate or a rate at a specific time (t)) and the integrated rate law for finding a specific concentration and deriving the half-life formula.

Posted: **Wed Mar 07, 2018 4:26 pm**

Since differential would be something like rate=k[A]^x[B]^y[C]^z, we can use it to:

calculate the rate given k, concentration of reactants, and order of reactants

calculate the rate constant k given rate, concentration of reactants, order of reactants

etc.

We cannot use it to calculate a new rate given an initial rate, or to calculate the time taken to get from x amount of reactant to y amount of reactant; we must use the integrated rate laws for this. Also, use integrated rate laws to find k given t, [A], and [A] initial.

Hope this is helpful!

calculate the rate given k, concentration of reactants, and order of reactants

calculate the rate constant k given rate, concentration of reactants, order of reactants

etc.

We cannot use it to calculate a new rate given an initial rate, or to calculate the time taken to get from x amount of reactant to y amount of reactant; we must use the integrated rate laws for this. Also, use integrated rate laws to find k given t, [A], and [A] initial.

Hope this is helpful!

Posted: **Sat Mar 10, 2018 5:48 pm**

You would use differential rate law if you need to find the rate given certain concentrations.

Integrated rate law is used for finding concentrations given a certain time, or finding a final concentration from an initial concentration.

Integrated rate law is used for finding concentrations given a certain time, or finding a final concentration from an initial concentration.

Posted: **Sun Mar 11, 2018 2:08 pm**

If you are given the concentration and time, use integrated rate law.