Ice Box

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Matt Sanruk 2H
Posts: 131
Joined: Wed Sep 18, 2019 12:21 am

Ice Box

Postby Matt Sanruk 2H » Wed Jan 15, 2020 11:06 pm

For ICE box, would the given concentrations always be a negative change?

Sarah Zhari 1D
Posts: 103
Joined: Sat Sep 14, 2019 12:16 am

Re: Ice Box

Postby Sarah Zhari 1D » Wed Jan 15, 2020 11:17 pm

If you are looking at a reaction where the reactants form products, the concentrations of the products would increase (a positive value in the C row) whereas the concentrations of the reactants would decrease (a negative value in the C row)

JasonLiu_2J
Posts: 109
Joined: Sat Aug 24, 2019 12:17 am

Re: Ice Box

Postby JasonLiu_2J » Wed Jan 15, 2020 11:18 pm

The given concentrations won't always have a negative change in concentration since sometimes you are given an initial concentration of both products and reactants and asked to calculate the equilibrium concentrations. In such a case, you would need to calculate Q using the initial concentrations of product and reactant and determine which the direction the reaction will proceed in to reach equilibrium. If Q>K and favors reactant formation, then products will decrease (have a change of -x), whereas if Q<K and favors product formation, reactants will decrease (change by -x)

MAC 4G
Posts: 121
Joined: Wed Sep 18, 2019 12:16 am

Re: Ice Box

Postby MAC 4G » Wed Jan 15, 2020 11:20 pm

I believe that based on the information you are given, like whether the products or the reactants are increasing or decreasing, would determine whether the change is positive or negative.
Something to keep in mind:
-If you are given initial concentrations and all of them are nonzero, calculate the reaction quotient Q.
-If the reaction moves toward the products, there would be +x for the products and -x for the reactants.
-If the reaction moves toward the reactants, there would be -x for the products and +x for the reactants.

Asha Agarwal 1E
Posts: 51
Joined: Fri Aug 30, 2019 12:16 am

Re: Ice Box

Postby Asha Agarwal 1E » Wed Jan 15, 2020 11:21 pm

The negative change is given to the reactant when you are given an initial concentration of reactants at the beginning because the system is proceeding from there. However, if you were given products and the reverse reaction were to occur to reach equilibrium, the negative change would be with the products.

Matt Sanruk 2H
Posts: 131
Joined: Wed Sep 18, 2019 12:21 am

Re: Ice Box

Postby Matt Sanruk 2H » Mon Jan 20, 2020 8:00 pm

Ok, so at times there will be reactants and products given you base the changed signs on the equilibrium

Juana Abana 1G
Posts: 100
Joined: Wed Sep 18, 2019 12:15 am

Re: Ice Box

Postby Juana Abana 1G » Mon Jan 20, 2020 10:15 pm

MAC 4G wrote:I believe that based on the information you are given, like whether the products or the reactants are increasing or decreasing, would determine whether the change is positive or negative.
Something to keep in mind:
-If you are given initial concentrations and all of them are nonzero, calculate the reaction quotient Q.
-If the reaction moves toward the products, there would be +x for the products and -x for the reactants.
-If the reaction moves toward the reactants, there would be -x for the products and +x for the reactants.


Thank you so much this is really helpful.

Matt Sanruk 2H
Posts: 131
Joined: Wed Sep 18, 2019 12:21 am

Re: Ice Box

Postby Matt Sanruk 2H » Wed Jan 22, 2020 9:43 pm

Do we get points off for not doing ICE boxes?

Hailey Kim 4G
Posts: 110
Joined: Sat Jul 20, 2019 12:16 am

Re: Ice Box

Postby Hailey Kim 4G » Wed Jan 22, 2020 9:48 pm

Matt Sanruk 2H wrote:Do we get points off for not doing ICE boxes?

I would make an ICE box just to be safe. This way, you can show all your work and less likely to make errors.

805422680
Posts: 103
Joined: Sat Sep 14, 2019 12:16 am

Re: Ice Box

Postby 805422680 » Wed Jan 22, 2020 10:01 pm

For an ICE box problem, the change would always be subtracted on the reactants side and added on the products side.


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