ICE BOX

[205150314]

when do we know that X is too small to be making a difference for the denominator in the ICE box?

[Hannah Pham]

You would X is too small when K < 10^3

[Charysa Santos 4G]

If your K is less than 10^-3, you can approximate the denominator.

[Anna Heckler 2C]

If X is smaller than 10^-3, then the affect of subtracting this value from the denominator is negligible.

[105311039]

when your K value is less than 10^-3 you can assume that it is too small to affect your concentration.

[Gabriel Ordonez 2K]

If the Kc, Ka, or Kb is smaller than 10^-3, then you can assume to remove the -x because it is small relative to the other number.

[Jesse Anderson-Ramirez 3I]

If any of the K values are smaller than 10^-3 then they are considered negligible.

[Ashley Nguyen 2L]

If the x is < 10^-3, then you can assume that the x has no effect on the denominator.

[Angus Wu_4G]

You can use the approximation if the K value is less than 1X10^-3. After you obtain your final H30+ concentration, you should also make sure the final H30+ concentration is less than 5% of the initial concentration of acid. If it is less than 5%, your approximation is probably fine. If your final concentration is greater than 5% of the initial acid, then your answer could be potentially off, depending on how many significant figures the problem has.

[vanessas0123]

x is too small if it's < 10^-3.

[Kishan Shah 2G]

yes, the cutoff is 10^-3.

However, I would advise only to use the short cut when the value is 10^-5 since you don't want to take a chance and have your answer be off by a few digits. On the test I would always check your answer using the quadratic formula if you used the short cut.

[005384106]

If K is 10^-3 then do you assume that x can be represented as 0.

[Jialun Chen 4F]

The cutoff is 10^-3. Yet in cases of weak acids and bases, one may want to check the % ionization to ensure the approximation is valid (i.e, the quadratic formula is still necessary if the final percentage is >5%).

[Juana Abana 1G]

When the K value is less than 10^-3 then you can assume that the K value it is too small to affect the concentration.

[Areli C 1L]

I would agree that 10^-3 would be the cut-off, but that margin is so close. 10^-4 or 10^-5 would be a safer option. If you do decide to neglect x at 10^-3 always check at the end if your answer is withing 5%.

[Matthew ILG 1L]

I believe that Dr. Lavelle said we can ignore x when K<10^-3.

[zfinn]

when x is <5% of the initial concentration you can omit it

[Eesha Chattopadhyay 2K]

if the k is smaller than 10^3, then the x in the ice box can be disregarded in the denominator.

[J Medina 2I]

If you exclude the x and want to double check afterwards to see if the approximation is accurate, then you can calculate the protonation percentage, or deprotonation percentage depending on the question, and if it is below 5% then the approximation is correct.

[Owen-Koetters-4I]

x is small when its less than 10^-3 of initial concentration of acid or base

[KHowe_1D]

X is too small when K<10^-3

[AronCainBayot2K]

If the number (x) is less than 10^-3

[Catherine Daye 1L]

When it’s smaller than 10^-3

[Sean Tran 2K]

If X is less than 10^-3

[Maria Poblete 2C]

If x is less than 10^-3, it can be considered negligible.

[Nathan Rothschild_2D]

You also should check again at the end with the 5% dissociation rule. Divide your x by the initial and if it is greater than 5%, then you can't assume it's negligible.

[Jacob Villar 2C]

When K is less than 10^-3, and you'll notice it is able to be approximated if x/initial concentration is less than 5%

[Ashley Alvarado 2C]

X will be too small if it is less than 5% of the initial and if K<10^-3.