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5% Rule

Posted: Sat Mar 14, 2020 5:37 pm
by Jose Robles 1D
Can someone elaborate what the 5% rule is?

Re: 5% Rule

Posted: Sat Mar 14, 2020 5:38 pm
by Kate Osborne 1H
when using the approximation (removing x when you are subtracting/adding it to something) you must check to make sure that x is less than 5% of the reactant that it is formed from (x will likely be H or OH- so you would use the acid or base)

Re: 5% Rule

Posted: Sat Mar 14, 2020 5:40 pm
by Jose Robles 1D
So if it meets the rule, do we just ignore the value?

Re: 5% Rule

Posted: Sat Mar 14, 2020 5:41 pm
by Brittney Hun 2C
You put the concentration you got from approximated the concentrations in the equilibrium values (from an ICE table) over the original concentration that's given and if it is less than 5% the approximation is sound, then if not then you have to use the quadratic formula to find the values.

Re: 5% Rule

Posted: Sat Mar 14, 2020 5:43 pm
by gabbymaraziti
You also know that you can use the approximation if your equilibrium constant, K, is small enough.

Re: 5% Rule

Posted: Sat Mar 14, 2020 5:58 pm
by JesseAuLec1Dis1G
The five percent rule is used in ICE tables. If the x value you get is 5% or less than the initial then you can ignore it. I believe that if the K is 10^-3 or less you can usually make this assumption.

Re: 5% Rule

Posted: Sat Mar 14, 2020 7:31 pm
by Madelyn Romberg 1H
Its for simplifying ICE calculations. If the end result is less than 5%, than the approximation is accurate.