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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.