Good day,
Regarding ICE tables, how would you know which x's would be positive or negative for the Change row?
I've heard to "always put the positive x's on the side with 0/no values"; is this correct? Also, what if both reactants and products were given a value -- which side would be positive or negative then? Thank you
Take the reaction A +B ==> Z and you mix 0.1M A and 0.1M B then you KNOW Z is zero to start so you put down
...................A + B ==> Z
I................0.1..0.1.........0, then
C...............-x......-x.........+x
If you start with A at 0.1 and B at 0.1 then some of A and some of B will react. You don't know how much so that is x. Thus -x for A and -x for B are leaving A and B. Whatever A and B lose must go to Z so C line is +x for Z. Then E line is the sum of I and C so the E line is
............0.1-x....0.1-x .........x
If one side has zero the +x goes there but I think it's better to work it through logically as I've done above.
For the case where both sides have a quantity listed for initial as in above
......................A + B ==> Z
I................0.1......0.1.......0.1
Now what? Some problems will tell you with the E line (equilibrium) is. Say
E................0.09. So you can calculate that change for A must be 0.1-0.09 = 0.01. If change for A is -0.01 then change for B must be 0.01 and change for Z must be +0.01. That finishes the E line to look like this.
.................0.09.........0.09...........0.11
What about the case where the E line is NOT given. Then it looks like this
..............A + B ==> Z
I...........0.01..0.01.....0.01
C..........
E............
In this case you don't know which way the reaction will shift (move) in order to reach equilibrium. So you will have the Keq given. Let's say it is 100. Now you compare Qeq with Keq like this.
Keq = 100 = (Z)/(A)(B)
Qeq = ;(0.1)/(0.1)(0.1)] = 10
To reach equilibrium, Q must be the same as K. It isn't so the reaction will move to the left or the right to make Q = K. You can see that Q at 10 is smaller than K at 100. How do we make Q larger. Easy. If the numerator is larger and the denominator is smaller that will make Q larger than 10. So the reaction will move to the right to make Z larger and A and B smaller so now you know the -x goes on the left and +x goes on the right.
Hope this helps. It's a little tough to do this without a blackboard and having you here in person.
No, that was a wonderful explanation! Thank you so much!
Good day to you too!
Ah, the mysterious x's in ICE tables, the algebraic unknowns that keep us on our toes. Now, let's tackle your question.
When filling out the Change row of an ICE table, it's not about positive or negative values for the x's. It's actually about the direction of the reaction. If the reaction moves forward, we say it's "positive," and if it moves backward, it's "negative." So, it's not a matter of placing positive or negative x's on a particular side.
If both reactants and products are given values, it implies that the reaction has already reached an equilibrium state. At equilibrium, the forward and backward reactions are occurring at the same rate, so both x's would be positive in this case.
Remember, it's all about understanding the direction of the reaction, not the sign of the x's. Stick with that, and you'll be the ICE-master in no time!
Hope this helps, and may the x's be ever in your favor.
Good day!
In an ICE table, the "x" values represent the changes in the concentrations of reactants and products during a chemical reaction. To determine whether the "x" values should be positive or negative in the Change row, you need to consider the stoichiometry of the reaction.
The general rule is that if a reactant is consumed (its concentration decreases), the corresponding "x" value should be negative. On the other hand, if a product is formed (its concentration increases), the corresponding "x" value should be positive.
Let's consider a simple example reaction: A + B -> C + D
If the initial concentrations of A and B are given, and you want to determine their change in concentration, you will put negative "x" values for A and B in the Change row. This is because they are being consumed during the reaction.
If the initial concentrations of C and D are given, and you want to determine their change in concentration, you will put positive "x" values for C and D in the Change row. This is because they are being formed during the reaction.
However, if both reactants and products have initial concentrations given, then you would need additional information to determine which side would have positive or negative "x" values. This additional information could be the stoichiometric coefficients of the reaction or any other relevant data provided.
It is important to note that the sign conventions for "x" values in an ICE table may vary depending on the specific problem or context. Therefore, it's always a good idea to carefully analyze the given information and follow any guidelines or instructions provided with the problem.
I hope this helps clarify your question! Let me know if there's anything else I can assist you with.
Good day! When using ICE tables, the x's represent the change in concentration for each species involved in the reaction. To determine whether the x's in the change row should be positive or negative, you need to consider the direction of the reaction.
If the reaction is proceeding from left to right (reactants to products), you would expect the concentrations of the reactants to decrease and the concentrations of the products to increase. Therefore, the x's for the reactants in the change row would be negative (indicating a decrease), while the x's for the products would be positive (indicating an increase).
Conversely, if the reaction is proceeding from right to left (products to reactants), the concentrations of the reactants would increase and the concentrations of the products would decrease. In this case, the x's for the reactants would be positive, while the x's for the products would be negative.
Following this logic, you can determine whether to assign positive or negative values to the x's depending on the direction of the reaction.
Regarding your question of what to do when both reactants and products have given values, it is important to provide more context. If you are given initial concentrations for both reactants and products, you would generally set up the change row in a way that reflects the direction of the reaction. The x's for the species that are decreasing in concentration would be negative, and the x's for the species that are increasing would be positive.
However, if you are given equilibrium concentrations for both reactants and products, you would not need to make any assumptions about the direction of the reaction. The equilibrium concentrations can directly be used to determine the values in the change row, without the need to assign positive or negative signs to the x's.
I hope this clarifies how to determine the signs of the x's in the change row of an ICE table. Feel free to ask if you have any further questions!