### 2nd order

Posted:

**Sun Mar 10, 2019 10:18 pm**Can someone explain why a second order graph has a positive slope? Does this mean that the concentration is increasing?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=149&t=44050

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Posted: **Sun Mar 10, 2019 10:18 pm**

Can someone explain why a second order graph has a positive slope? Does this mean that the concentration is increasing?

Posted: **Mon Mar 11, 2019 1:08 am**

The second order graph has nothing to do with the concentration, but rather the second derivative.

Posted: **Mon Mar 11, 2019 2:16 am**

The y-axis is the inverse of the concentration of A. Thus, the slope shows that as time increases, the inverse of [A] increases (not [A] itself).

Posted: **Mon Mar 11, 2019 2:33 am**

Do we also have to know or study the graphs for half-life?

Posted: **Mon Mar 11, 2019 4:10 pm**

Since the graph is 1/A v time and when you integrate that you'll get 1/[A] = kt + 1/[A]o, and when you plot 1/[A] against t you'll get a positive slope because k is positive