ICE Charts: Videos & Practice Problems

ICE charts, standing for Initial, Change, and Equilibrium, are essential tools in chemistry for simplifying the calculations of equilibrium reactions. They are particularly useful when multiple equilibrium amounts for compounds in a balanced chemical reaction are unknown. The units used in ICE charts are atmospheres for the equilibrium constant K_p or molarity for K_c. These charts not only assist in determining equilibrium amounts but also in organizing data to calculate the equilibrium constant, K, which is the ratio of product to reactant concentrations at equilibrium. When only one equilibrium amount is provided, ICE charts can be pivotal in solving for K, streamlining the process of understanding chemical equilibria.

ICE Charts and Equilibrium Amount

ICE charts, which stand for Initial, Change, and Equilibrium, are essential tools used in the study of chemical equilibrium. They serve to simplify the calculations involved in equilibrium reactions, particularly when more than one equilibrium amount is unknown. This structured approach allows for a clearer understanding of how concentrations or pressures of reactants and products change as a system reaches equilibrium.

In an ICE chart, the initial concentrations or pressures of the reactants and products are recorded in the first row. The second row captures the changes that occur as the reaction progresses, while the final row reflects the equilibrium concentrations or pressures. The units used in ICE charts are typically in atmospheres (for the equilibrium constant \( K_p \)) or in molarity (for the equilibrium constant \( K_c \)). This distinction is crucial, as it directly relates to the type of equilibrium constant being utilized.

Utilizing ICE charts is particularly beneficial when dealing with complex equilibrium equations, as they help organize the necessary information systematically. By clearly laying out the initial conditions, the changes that occur during the reaction, and the final equilibrium states, students can more easily solve for unknown quantities and understand the dynamics of the reaction. Remember, ICE charts are a valuable resource whenever multiple equilibrium amounts are missing in a balanced chemical reaction.

Calculate Equilibrium Amount with ICE Chart Example

The formation of hydrogen iodide (HI) from hydrogen gas (H₂) and iodine gas (I₂) can be represented by the balanced chemical equation:

H₂(g) + I₂(g) ⇌ 2 HI(g)

At 25 degrees Celsius, the equilibrium constant (K_c) for this reaction is 0.0218. To find the equilibrium concentration of hydrogen iodide when the initial concentrations of H₂ and I₂ are both 0.10 M and there is no HI present initially, we can use an ICE (Initial, Change, Equilibrium) chart.

Initially, we have:

• [H₂] = 0.10 M
• [I₂] = 0.10 M
• [HI] = 0 M

As the reaction proceeds, let x be the change in concentration of H₂ and I₂ that reacts. The changes in concentration can be represented as:

• [H₂] = 0.10 - x
• [I₂] = 0.10 - x
• [HI] = 2x

Substituting these expressions into the equilibrium constant expression:

K_c = \(\frac{[HI]^2}{[H_2][I_2]}\)

We can write:

0.0218 = \(\frac{(2x)^2}{(0.10 - x)(0.10 - x)}\)

To simplify, we can take the square root of both sides, which allows us to avoid the quadratic formula:

\(\sqrt{0.0218} = \frac{2x}{0.10 - x}\)

Calculating the square root gives:

0.1476 = \(\frac{2x}{0.10 - x}\)

Cross-multiplying yields:

0.01476 - 0.1476x = 2x

Rearranging gives:

0.01476 = 2.1476x

Solving for x results in:

x = \(\frac{0.01476}{2.1476} \approx 0.00688\)

To find the equilibrium concentration of hydrogen iodide, we use the relationship [HI] = 2x:

[HI] = 2(0.00688) = 0.01376 M

Thus, the equilibrium concentration of hydrogen iodide in the sealed reaction vessel is 0.01376 M.

At a given temperature the gas phase reaction: N₂ (g) + O₂ (g) ⇄ 2 NO (g) has an equilibrium constant of 4.18 x 10^-7. What will be the concentration of NO at equilibrium if 2.00 moles of nitrogen and 6.00 moles oxygen are allowed to come to equilibrium in a 2.0 L flask?

• A. 1.1 × 10⁻³ M
• B. 3.1 × 10⁻⁷ M
• C. 1.2 × 10⁻⁶ M
• D. 6.2 × 10⁻⁷ M

Answer: (A)

Consider the following reaction:
COBr2 (g) ⇌ CO (g) + Br2 (g)
A reaction mixture initially contains 0.15 atm COBr2. Determine the equilibrium concentration of CO if Kp for the reaction at 25°C is 4.08.

• A. 0.782 atm
• B. 0.145 atm
• C. 0.005 atm
• D. 4.225 atm

Answer: (B)

ICE Charts and Equilibrium Constant

Ice charts, which stand for Initial, Change, and Equilibrium, are valuable tools in chemistry for organizing information related to chemical equilibria. They help in determining both the equilibrium amounts of reactants and products, as well as calculating the equilibrium constant, denoted as K.

The equilibrium constant K is defined as the ratio of the concentrations of products to the concentrations of reactants at equilibrium. Mathematically, it can be expressed as:

K = \frac{[products]}{[reactants]}

When provided with a single equilibrium concentration, it is possible to derive the equilibrium constant. This involves using the known equilibrium amount to backtrack and find the initial concentrations and the changes that occurred during the reaction. By substituting these values into the equilibrium expression, one can solve for K.

Understanding how to manipulate these values is crucial for predicting the behavior of chemical systems and for performing calculations related to equilibrium. Mastery of this concept allows for a deeper comprehension of dynamic chemical processes and their applications in various scientific fields.

Calculate Equilibrium Constant with ICE Chart Example

In the formation of acid rain, a significant reaction occurs where 2 moles of sulfur dioxide (SO₂) react with 1 mole of oxygen gas (O₂) to produce 2 moles of sulfur trioxide (SO₃). The reaction can be represented as:

2 SO₂ + O₂ ⇌ 2 SO₃

To calculate the equilibrium constant (K_c) for this reaction at 340 degrees Celsius, we start with the initial concentrations: 0.30 M of SO₂ and 0.20 M of O₂. At equilibrium, the concentration of SO₃ is found to be 0.0150 M.

We can use an ICE (Initial, Change, Equilibrium) table to track the changes in concentration. Initially, the concentrations are:

• SO₂: 0.30 M
• O₂: 0.20 M
• SO₃: 0 M

As the reaction proceeds, we denote the change in concentration of SO₂ as -2x, for O₂ as -x, and for SO₃ as +2x. Thus, the equilibrium concentrations can be expressed as:

• SO₂: 0.30 - 2x
• O₂: 0.20 - x
• SO₃: 2x

Given that at equilibrium, SO₃ = 0.0150 M, we can set up the equation:

2x = 0.0150 M

From this, we find:

x = 0.0075 M

Now, substituting x back into the expressions for the equilibrium concentrations gives us:

• SO₂: 0.30 - 2(0.0075) = 0.285 M
• O₂: 0.20 - 0.0075 = 0.1925 M
• SO₃: 0.0150 M (as given)

Next, we can set up the equilibrium constant expression:

K_c = \(\frac{[SO_3]^2}{[SO_2]^2 \cdot [O_2]}\)

Substituting the equilibrium concentrations into the expression yields:

K_c = \(\frac{(0.0150)^2}{(0.285)^2 \cdot (0.1925)}\)

Calculating this gives:

K_c = 0.01439

Considering significant figures, the final value for the equilibrium constant is reported as:

K_c = 0.014

It is important to note that equilibrium constants are dimensionless, meaning they have no units.

At a certain temperature, 0.810 mol NO is placed in a 5.00 L container. At equilibrium, 0.075 mol N₂ is present. Calculate K_c. 
2 NO (g) ⇌ N₂ (g) + O₂ (g)

• A. 0.013
• B. 0.026
• C. 0.66
• D. 0.11

Answer: (A)

When 0.600 atm of NO­­₂ was allowed to come to equilibrium the total pressure was 0.875 atm. Calculate the K_p­ of the reaction. 
2 NO₂ (g) ⇌ 2 NO (g) + O₂ (g)

• A. 1.66
• B. 3.02
• C. 60.5
• D. 33.3

Answer: (D)

Here’s what students ask on this topic:

How to do ICE charts?

An ICE chart is a tool used in chemistry to keep track of the changes in concentration for each species in a chemical reaction. ICE stands for Initial, Change, and Equilibrium. Here's how to create and use an ICE chart:

1. Write down the balanced chemical equation for the reaction.
2. Below the equation, create a chart with three rows labeled "I" for initial concentrations, "C" for change in concentrations, and "E" for equilibrium concentrations.
3. Fill in the initial concentrations of reactants and products. If a product is not present initially, its concentration is zero.
4. Use stoichiometry to determine the changes in concentration. These changes are often represented by 'x', which is added or subtracted from the initial concentrations to find the equilibrium concentrations. The changes should reflect the molar ratios from the balanced equation.
5. Apply the changes to the initial concentrations to calculate the equilibrium concentrations. For reactants, the change will be a subtraction, and for products, it will be an addition.
6. If you are given the equilibrium concentration for one species, you can calculate 'x' and then find the equilibrium concentrations for all other species.

Remember, the direction of the change (whether you add or subtract 'x') depends on whether the reaction is proceeding forward or in reverse.

How can ICE charts be solved?

An ICE chart, which stands for Initial, Change, and Equilibrium, is a tool used to solve equilibrium problems in chemistry. Here's how to solve an ICE chart step by step:

1. Identify the balanced chemical equation for the reaction and write it at the top of your chart.
2. Initial Concentrations: Write down the initial concentrations of reactants and products. If a substance is not present initially, write 0.
3. Change: Determine the change in concentration for each substance as the system moves towards equilibrium. Use variables like 'x' to represent this change. If the reaction consumes a reactant, the change will be negative (-x), and if it produces a product, the change will be positive (+x).
4. Equilibrium Concentrations: Add the initial concentration and change together to find the equilibrium concentrations for all substances.
5. Write the equilibrium expression for the reaction using the equilibrium concentrations.
6. Solve for 'x': Use the equilibrium constant (K) given for the reaction to solve for 'x'. This may involve some algebraic manipulation.
7. Check: Plug the value of 'x' back into the equilibrium concentrations to ensure they make sense chemically (e.g. no negative concentrations).
8. Answer: Now that you have the value of 'x', you can determine the equilibrium concentrations of all species involved.

How do you use ICE charts?

An ICE chart (which stands for Initial, Change, Equilibrium) is a tool used to keep track of the concentrations of reactants and products during a chemical reaction, especially when dealing with equilibrium reactions.

Here's how to use an ICE chart:

1. Identify the reaction: Write down the balanced chemical equation for the reaction you're analyzing.
2. Initial concentrations: List the initial concentrations (or pressures) of the reactants and products before any reaction has occurred under the "I" column. If a product is not present initially, its concentration is zero.
3. Change in concentrations: Under the "C" column, indicate the changes in concentrations (or pressures) as the reaction progresses. Use variables like 'x' to represent these changes. If the reaction consumes reactants, the change will be negative; if it produces more products, the change will be positive.
4. Equilibrium concentrations: Under the "E" column, express the equilibrium concentrations (or pressures) of the reactants and products. This is done by adding the initial concentrations and the changes together.
5. Apply the equilibrium constant: Use the equilibrium constant expression for the reaction to relate the changes in concentrations to the known equilibrium constant value. Solve for the unknown variable.
6. Solve for concentrations: Once you have the value of the change (x)