## negative and k

Jonathan Pai 2I
Posts: 121
Joined: Fri Sep 28, 2018 12:27 am

### negative and k

A first order problem asks to find k, so we used ln[A]=-kt+ln[A]o, but in the solution ignore the negative k value. I thought k could be negative because dont 1st and 0th order have negative slopes in their graph. Do we ignore the negative or how does this work?

Kyle Golden Dis 2G
Posts: 67
Joined: Fri Sep 28, 2018 12:17 am

### Re: negative and k

The "k" value can never be negative. For a first order reaction, the slope=-k. Since the slope is negative, k is the opposite sign of what ever the slope is.

Cole Doolittle 2K
Posts: 30
Joined: Fri Sep 28, 2018 12:20 am

### Re: negative and k

K cannot be negative because you can't have a negative concentration

Alysa Rallistan 2G
Posts: 32
Joined: Thu Jan 17, 2019 12:16 am

### Re: negative and k

The negative in the equation already accounts for the negative slope however the actual value of the rate constant cannot be negative as seen from its units mol/L/s since time is involved you cannot have negative time