## What does Kc have to be less than for you to estimate?

Nathan Tran 4K
Posts: 92
Joined: Fri Sep 28, 2018 12:16 am

### What does Kc have to be less than for you to estimate?

What value does Kc have to be less than for you to estimate, meaning you can negate the -x term when employing ice method to solving for concentrations of products given initial reactant concentration? Is it less than 10^-3 or something else? Just making sure!

Josephine Lu 4L
Posts: 62
Joined: Fri Sep 28, 2018 12:18 am

### Re: What does Kc have to be less than for you to estimate?

if Kc<10^-3, then you can use the approximation and ignore x in the denominator

Posts: 37
Joined: Mon Apr 23, 2018 3:00 am

### Re: What does Kc have to be less than for you to estimate?

You can also double check by calculating the percent ionization. If it's less than 5%, the approximation is valid.

Arta Kasaeian 2C
Posts: 30
Joined: Mon Jan 07, 2019 8:22 am

### Re: What does Kc have to be less than for you to estimate?

I would personally use the 5% rule (percent protonation should be less than this) to approximate.