ignoring x

[marcus lin 1E]

so for some of the ICE table calculations we ignore x and just pretend it's 0, when do we do that?

[BenJohnson1H]

When k is equal to or less than 10^3 you can omit any X that is being added or subtracted. To check, see if the dissociation of the acid/base is equal to or lower than 5%.

[Miriam Sheetz 2B]

You can ignore x in the ice table when the K value is less than 10^-3 because it the percent ionization will be less than 5%.

[Erin Kim 2G]

You can ignore x in some instances because the amount that dissociates will be so little that it is insignificant to the overall decrease in the molarity. If the K value is extremely small, namely less than 10^-3, it means that reactants are favored in the reaction and so little of the reactants will be converted into products and therefore, the x value is so little and its subtraction is negligent.

[Ian Marquez 2K]

Also, it is important to keep in mind that x is not actually 0 because if you plug in 0 for all x's it will be impossible to solve for x. However, it is useful in approximations to make the calculations more simple as the other replies have stated.

[sonalivij]

Keep in mind that x is only considered to be 0 when it is being added or subtracted to a number, not when it is alone and being multiplied

[Kevin Tang 4L]

You can ignore x in an equilibrium equation when the percent deprotonation or protonation is less than 5%. This is because x will be negligible in the denominator related to the other initial value.

Hope this helps correct me if i'm wrong.

[Sapna Ramappa 1J]

If the K value is less than 10^-3, you can ignore the x in the denominator if it is being added or subtracted to the initial concentration. This is because it'll make such a minute difference in the equilibrium concentration as a whole. Be careful that you don't just substitute all the x values with 0!

[Diana Sandoval 1K]

When k is equal to or less than 10^3.

[Tony Chung 2I]

you can ignore x when youre approximating. this is when your k value is less than or equal to 10^-3

[Luis_Yepez_1F]

You can ignore x when k is less than 1x10^-3

[Mark 1D]

X is zero if follows 5% rule or if K is less than 10^-3. Therefore no need to use quadratic equation

[jlinwashington1B]

X can be ignored when k is less than 1x10^-3

[Sarah_Kang_2K]

You can ignore x when approximating (when K<10^-3), but make sure to check your work after to make sure x is indeed less than or equal to 5% deprotonation!

[sonalivij]

A good way to check if your approximation was valid is to see if x is less than 5% of the initial concentrations

[Nghi Nguyen 2L]

when K is less than 1*10^-3 but I think Dr. Lavelle said on the midterm that he wants use to always use the quadratic formula so I can only assume that applies to the final as well

[Jacqueline Duong 1H]

We can ignore x when the 5% rule applies to it, which is when x is less than 5% of the initial concentration.