## If slope for ln(A) vs. t is negative is k?

$\frac{d[R]}{dt}=-k[R]; \ln [R]=-kt + \ln [R]_{0}; t_{\frac{1}{2}}=\frac{0.693}{k}$

Nicole Leppi 2K
Posts: 20
Joined: Fri Sep 26, 2014 2:02 pm

### If slope for ln(A) vs. t is negative is k?

For example if a slope for a first order reaction (ln(A)) vs. t) was -3 would k=-3 or would k=3?

Neil DSilva 1L
Posts: 70
Joined: Fri Sep 26, 2014 2:02 pm

### Re: If slope for ln(A) vs. t is negative is k?

The negative sign is added so that the slope can be negative while k remains positive, so if the slope was -3:
$slope = -3 = -k$
and k is just 3 (still positive).

Just remember, the proportionality constant, k, is always positive.