5% rule

[Jorja De Jesus 2C]

What is the 5% rule and how do you apply it?

[Alexandra Bartolome 2H]

When calculating the percent ionization and it is less than 5%, it confirms that the approximation of x in the ICE table is okay and the use of the quadratic formula is not necessary.

[805097738]

because the change in x is so small, the original molarity of the molecule being changed by x is a suffice approximation.

[Robert Tran 1B]

If the percent deprotonation is less that 5%, then when we calculate equilibrium concentrations, we can ignore the x values relative to the initial concentration because it is not significant.

[Andres Merlos 2L]

The 5% rule generally applies to approximation when trying to find x, after performing an ICE table. Instead of using the quadratic formula, you can disregard x relative to the initial if what you get from the approximation is less than 5% of the initial value. The procedure to finding that value is through the percent Ionization.

[Matt F]

The 5% rule can be applied after making an approximation for x. You calculate x/[initial concentration given] and if the value is less than 5% (0.05) then the approximation is valid. However, if the value is greater than 5% then you must reject the approximation and recalculate x

[Cavalli_1H]

it means you can only approximate a value for x on an ice table. you can sidestep the quadratic equation when you apply the approximation threshold. you do this because the value is so insignificant that it doesn't necessarily affect the solution

[Ritu Gaikwad 2E]

The 5% rule is used normally in indicating if when setting up the Kc expression if x should be factored into the concentration of the initial reactant. You normally approximate without using that x and if the resulting value x/(initial conc) is less than 5% it is valid to not factor that x in the concentration of the initial reactant.

[kevinolvera1j]

The 5% rule is sort of like checking your work. If you approximated by ignoring x, if the percent ionization was less than 5%, then the approximation was fine.

[Charysa Santos 4G]

The 5% rule is for checking whether or not your approximation is valid. This is usually if the K is less than 10^-3 and you take out the X from the denominator of your equilibrium expression.

[Trent Yamamoto 2J]

The 5% Rule essentially means you can approximate the value for x on an ice table because the value is so small it doesn't make a significant change in the concentration. For example, Professor Lavelle talked about how a millionaire giving away $1,000 would barely notice the difference.