ICE Chart Question

Moderators: Chem_Mod, Chem_Admin

Hasmik Dis 2F
Posts: 120
Joined: Wed Sep 30, 2020 9:50 pm

ICE Chart Question

Postby Hasmik Dis 2F » Mon Jan 25, 2021 5:37 am

Does anyone know why when creating ICE charts, and we have a decrease of "-2x" we still have to include the "2" as an exponent when writing out the constant equation?
For example, if my product is -2x, and whenever it's time to calculate either K or for X, we would then do products over reactants. The products in this case would be (2x)^2. However, isn't this double-counting the coefficient of 2? We already incorporate it when saying -2x, so why do we include it again in the exponent?

Laura 3l
Posts: 118
Joined: Wed Sep 30, 2020 9:55 pm
Been upvoted: 1 time

Re: ICE Chart Question

Postby Laura 3l » Mon Jan 25, 2021 6:01 am

You would still have to include the coefficient 2 as an exponent so it would be [-2x]^2 in your equilibrium equation.
I know it seems like it is taking it into account two times but I'm honestly not sure exactly why...

Madison Wong 3H
Posts: 105
Joined: Wed Sep 30, 2020 9:35 pm
Been upvoted: 2 times

Re: ICE Chart Question

Postby Madison Wong 3H » Mon Jan 25, 2021 9:11 am

You still include the coefficient in calculation for the equilibrium constant. I think this is because the ()^2 accounts for the coefficient in the equilibrium constant calculation while the -2x matters in relation to the molar ratios of other reactants and products.

sophie esherick 3H
Posts: 124
Joined: Wed Sep 30, 2020 9:35 pm
Been upvoted: 6 times

Re: ICE Chart Question

Postby sophie esherick 3H » Mon Jan 25, 2021 9:20 am

You would still have to include the coefficient 2 as an exponent so it would look like [-2x]^2 in your K equation. I'm not entirely sure why we include both but I'm assuming it is because the -2 in -2x matters since it relates to molar ratios of the reactants and other products (whatever x is, since there are two moles of it in the balanced equation you would multiply that x concentration by 2). The ^2 I think is used to acknowledge the coefficient within the equilibrium equation but again I'm not 100% sure.

Aditya Sundaram 3D
Posts: 43
Joined: Wed Nov 18, 2020 12:23 am

Re: ICE Chart Question

Postby Aditya Sundaram 3D » Mon Jan 25, 2021 9:25 am

Hasmik Dis 2F wrote:Does anyone know why when creating ICE charts, and we have a decrease of "-2x" we still have to include the "2" as an exponent when writing out the constant equation?
For example, if my product is -2x, and whenever it's time to calculate either K or for X, we would then do products over reactants. The products in this case would be (2x)^2. However, isn't this double-counting the coefficient of 2? We already incorporate it when saying -2x, so why do we include it again in the exponent?


The 2 is essential to finding the relative proportions and calculating the molar concentration differences from initial to equilibrium constants.

Nick Saeedi 1I
Posts: 112
Joined: Wed Sep 30, 2020 9:39 pm

Re: ICE Chart Question

Postby Nick Saeedi 1I » Mon Jan 25, 2021 5:17 pm

Yes it is also included in the exponent.

Jason Knight - 1F
Posts: 113
Joined: Wed Sep 30, 2020 9:55 pm

Re: ICE Chart Question

Postby Jason Knight - 1F » Tue Jan 26, 2021 8:38 am

When creating ICE charts, even when we decrease by [-2x] we still have to include the ^2 in the equilibrium concentration. For example, in this situation our equilibrium expression for a acid/base with a molar coefficient of 2 will look like [2x]^2.

Mursall M 2A
Posts: 60
Joined: Wed Nov 18, 2020 12:20 am

Re: ICE Chart Question

Postby Mursall M 2A » Tue Jan 26, 2021 8:46 am

You would still need to include the exponent because the 2x on the inside is only representing the concentration. So when you calculate K, you just treat the 2x as a concentration, and plug it into your equation.

Becca Nelson 3F
Posts: 114
Joined: Wed Sep 30, 2020 9:52 pm

Re: ICE Chart Question

Postby Becca Nelson 3F » Tue Jan 26, 2021 9:31 am

Lets say your equation is O2 +2H2 -> 2H2O and you start with only 1 mol hydrogen gas and oxygen.

For every two water molecule made you will loose 2 hydrogens and 1 oxygen, so your ICE table would have -x for change for oxygen, -2x for hydrogen and +2x for water. In your equilibrium it would be 1-x and 1-2x. You still square the hydrogen and water because they have the coefficients of 2.

your final K would be (2x)^2/([1-x][1-2x]^2). Hope this helps!

Kimiya Aframian IB
Posts: 131
Joined: Wed Sep 30, 2020 9:34 pm

Re: ICE Chart Question

Postby Kimiya Aframian IB » Tue Jan 26, 2021 10:20 am

Hasmik Dis 2F wrote:Does anyone know why when creating ICE charts, and we have a decrease of "-2x" we still have to include the "2" as an exponent when writing out the constant equation?
For example, if my product is -2x, and whenever it's time to calculate either K or for X, we would then do products over reactants. The products in this case would be (2x)^2. However, isn't this double-counting the coefficient of 2? We already incorporate it when saying -2x, so why do we include it again in the exponent?

Hi! The reason that we need to do -2x or +2x is because there are two moles so the change must be at this ratio as well. Then, we need to square it because when calculating our K value, the concentration (or partial pressure) but be raised to the power of its coefficient. Hope this helps!

Andy Hon 3E
Posts: 55
Joined: Wed Nov 18, 2020 12:27 am

Re: ICE Chart Question

Postby Andy Hon 3E » Wed Jan 27, 2021 12:52 am

You would leave it in because the -2x gives you the equilibrium concentration. You use that equation to plug it into the equilibrium constant equation. You would still have to square it or raise it to its stoichiometric coefficient.

Claudia_Danysh_2B
Posts: 99
Joined: Wed Sep 30, 2020 9:58 pm

Re: ICE Chart Question

Postby Claudia_Danysh_2B » Sun Jan 31, 2021 2:12 pm

Yes, we still include 2 in the K equation!!

Liam Bertrand 3
Posts: 101
Joined: Wed Sep 30, 2020 9:53 pm

Re: ICE Chart Question

Postby Liam Bertrand 3 » Sun Jan 31, 2021 2:12 pm

You would still take into account the exponents.

Chinmayi Mutyala 3H
Posts: 105
Joined: Wed Sep 30, 2020 9:50 pm

Re: ICE Chart Question

Postby Chinmayi Mutyala 3H » Sun Feb 07, 2021 11:18 pm

2x is considered to be the concentration of that compound. When you calculate K, you do each concentration to the power of it's stoichiometric coefficient so it would be (2x)^n. The exponent would be on the 2 as well.

Michael Cardenas 3B
Posts: 66
Joined: Wed Sep 30, 2020 9:34 pm

Re: ICE Chart Question

Postby Michael Cardenas 3B » Sun Feb 07, 2021 11:31 pm

You would still use the exponents because they are a part of the equation for Q, which is separate from the ice chart.

Charmaine Ng 2D
Posts: 108
Joined: Wed Sep 30, 2020 9:37 pm

Re: ICE Chart Question

Postby Charmaine Ng 2D » Sun Feb 07, 2021 11:36 pm

Yep, you would still take them into consideration for the exponents! :))

Jacob Schwarz-Discussion 3I
Posts: 111
Joined: Wed Sep 30, 2020 10:01 pm

Re: ICE Chart Question

Postby Jacob Schwarz-Discussion 3I » Thu Feb 25, 2021 4:29 pm

Yes you still do take it into consideration for the exponents. This is because the -2x accounts for the molar concentrations whereas the ^2 exponent is related to the equilibrium concentration.

Lorena_Morales_1K
Posts: 53
Joined: Wed Sep 30, 2020 10:11 pm

Re: ICE Chart Question

Postby Lorena_Morales_1K » Fri Mar 12, 2021 12:36 pm

Yes you still do take it into consideration for the exponents.

Sara Sandri 2B
Posts: 60
Joined: Wed Nov 18, 2020 12:18 am

Re: ICE Chart Question

Postby Sara Sandri 2B » Fri Mar 12, 2021 3:22 pm

Coefficients matter for both what you subtract (-2X) and what power your raise the concentration 2. I was confused on this as well!

tholz11
Posts: 108
Joined: Wed Sep 30, 2020 9:38 pm

Re: ICE Chart Question

Postby tholz11 » Mon Mar 15, 2021 9:29 pm

You have to account for it "twice," once by writing in 2x and then a second time by squaring the concentration in the K expression.

Constance Newell
Posts: 100
Joined: Wed Sep 30, 2020 9:38 pm

Re: ICE Chart Question

Postby Constance Newell » Mon Mar 15, 2021 9:39 pm

You have to do both, I can't explain why but I guess the concentration has some sort of exponential effect on the constant

Britney Tran IJ
Posts: 103
Joined: Fri Aug 30, 2019 12:18 am

Re: ICE Chart Question

Postby Britney Tran IJ » Mon Mar 15, 2021 10:13 pm

yeah you have to consider the coefficients for the exponents

Diana Aguilar 3H
Posts: 120
Joined: Wed Sep 30, 2020 9:50 pm

Re: ICE Chart Question

Postby Diana Aguilar 3H » Mon Mar 15, 2021 10:42 pm

Hi! I believe you still have to take into consideration the coefficients for the exponents when writing the constant equation.

Naomi Hernandez-Ramirez 1J
Posts: 70
Joined: Wed Feb 19, 2020 12:17 am

Re: ICE Chart Question

Postby Naomi Hernandez-Ramirez 1J » Tue Mar 16, 2021 8:37 am

even when you decrease by -2x you still have to include the ^2 in the equilibrium concentration

Audrey Banzali-Marks 1A
Posts: 108
Joined: Fri Sep 24, 2021 6:32 am

Re: ICE Chart Question

Postby Audrey Banzali-Marks 1A » Wed Jan 05, 2022 6:22 pm

You have to include the 2 in 2x because it's fully counting the concentration of the associated reactant or product. For example, if you have Cl2 <-> 2 Cl, you have to include K = [2x]^2/[Cl2-x] because if you wrote K=[x]^2/[Cl2-x], it would only count half of the product's concentration. The formula for K is K=[product concentration]^coefficient/[reactant concentration]^coefficient, so you won't be double counting if you include the 2 and square it because the coefficient-power part is unrelated to the concentration. I hope that helps!

Naomi Christian 1E
Posts: 104
Joined: Fri Sep 24, 2021 5:45 am

Re: ICE Chart Question

Postby Naomi Christian 1E » Wed Jan 05, 2022 8:47 pm

Yes, you would still have to include the 2. It is because this coefficient relates to the change in molar concentration, and is not related to the stoichiometric coefficient. If you don't you will get the wrong answer.

Michelle Argueta 1E
Posts: 103
Joined: Fri Sep 24, 2021 6:53 am

Re: ICE Chart Question

Postby Michelle Argueta 1E » Thu Jan 06, 2022 11:04 pm

Hello! I believe that you still have to use the "2" in consideration of the exponent as it is still the coefficient of one of the reactants and/or products and therefore important when solving for the equilibrium constant. The squaring of the concentration when solving for the equilibrium constant is important to include in order to get the accurate K.


Return to “Non-Equilibrium Conditions & The Reaction Quotient”

Who is online

Users browsing this forum: No registered users and 2 guests