2 Positive X-Values in ICE Table

[Kiiana Hilario 2E]

When using the ICE table to solve for x, if you are given two positive x values, how do you know which one to use?

[Jasmine Winter 1A]

Very rarely will there be two positive x values; however, in the case that this occurs, you should individually subtract both x values from the initial concentration provided by the problem. If one of the x values provides a negative equilibrium value for concentration, then the other x value should be selected.

[Brandon_G_1H]

Hello! Like the reply above, if you do get 2 positive values when solving the quadratic, then plug them both in the original equation and disregard the x that gives you a negative value.

[Dylan Cho 3H]

Hello,

Whenever you get two positive values, one is normally going to be larger than the initial concentrations given. Because of this, subtracting from the initial concentration would give you a negative concentration which isn't possible. Therefore, you would want to compare the values and use the one that gives you a positive, not a negative.

Hope this helps! :)

[Payton Zarceno 1E]

Hi! Usually, if I get two positive values one is considerably more significant than the other and doesn't make sense to use in the equation. But if you have two positive values I would suggest subtracting it from the initial concentration, one of the values should give you an unusable negative value.

[Vivian_Lau_2D]

Hello. After solving for the quadratic equation, you would usually get a negative and positive value for X and use only the positive value to solve for the equilibrium molar concentrations. However, if you get two positive values for X, plug both X values into the equilibrium concentration equations, and use the X value that will give you positive equilibrium molar concentrations for all reactants and products in the reaction. Hope this helps!

[Ashlynn_Chen_3H]

When using the ICE table to solve for x, if you are given two positive x values, how do you know which one to use?

if you found 2 positive x values, you use the x value that will not give a negative concentration at equilibrium. Typically, one of the positive x values will be very large or just light large enough so when you calculate equilibrium concentration (initial concentration-X) it will be negative which is not realistic. So that's how you choose the x value