## half life

$aR \to bP, Rate = -\frac{1}{a} \frac{d[R]}{dt} = \frac{1}{b}\frac{d[P]}{dt}$

josmit_1D
Posts: 107
Joined: Fri Aug 09, 2019 12:17 am

### half life

from the half life equation, how do we determine how long it takes the concentration to decrease to other levels such at 1/4 or 1/16 of its original value?

PranaviKolla2B
Posts: 114
Joined: Fri Aug 30, 2019 12:17 am

### Re: half life

Since it takes a certain amount of time to become half of the original value (its half life), it would take double the half-life to get to 1/4 of the original amount.

romina_4C
Posts: 100
Joined: Thu Jul 11, 2019 12:17 am

### Re: half life

For those types of problems, you just have to use the integrated rate law equations (specified for which order reaction it is). In that case, your [A] will be (1/16)[A]initial, or whatever fraction of the initial the problem specifies.

Natalie Benitez 1E
Posts: 100
Joined: Fri Aug 02, 2019 12:15 am

### Re: half life

Based on the half-life you calculated in order to get to get to 1/4 or say 1/6 you would double or triple the half-life you got.

Matthew Tsai 2H
Posts: 101
Joined: Wed Sep 18, 2019 12:20 am

### Re: half life

You would use the same integrated rate law depending on the order of reaction and set concentration to 1/4, 1/8, etc. of the initial concentration and solve for t.

kausalya_1k
Posts: 50
Joined: Wed Nov 14, 2018 12:23 am

### Re: half life

you would use the integrated rate law in order to find it for values after 1/2 (such as 1/4 and 1/16)