Page **1** of **1**

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

Posted: **Tue Jan 22, 2019 12:03 am**

by **Nathan Tran 4K**

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!

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

Posted: **Tue Jan 22, 2019 12:04 am**

by **Josephine Lu 4L**

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

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

Posted: **Tue Jan 22, 2019 12:06 am**

by **Madeline Ho 1C**

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

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

Posted: **Tue Jan 22, 2019 1:50 am**

by **Arta Kasaeian 2C**

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