5% Rule

[Jose Robles 1D]

Can someone elaborate what the 5% rule is?

[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)

[Jose Robles 1D]

So if it meets the rule, do we just ignore the value?

[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.

[gabbymaraziti]

You also know that you can use the approximation if your equilibrium constant, K, is small enough.

[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.

[Madelyn Romberg 1H]

Its for simplifying ICE calculations. If the end result is less than 5%, than the approximation is accurate.