# Solve 3 Chemical Equilibrium Questions & Calculate Kc

• Maximillien
In summary, the conversation covers questions related to equilibrium constant, temperature, and calculations for a chemical reaction. The first question discusses how the equilibrium constant at a certain temperature can only have one value and how the units for concentration do not affect its calculation. The second question involves comparing two different temperatures and determining which one will result in a higher amount of B at equilibrium. The third question provides information on a gas mixture injected into a container and asks for the calculation of the equilibrium constant at a specific temperature.
Maximillien
Hi, I have 3 questions i can't seem to solve anyways thanks in advance.

1) If the equilbrium constant at a cetain temperature is 24 for the reaction, 2NO(g) <-> N2(g) + 02(g). Both of the systems listed below cannon be in equilbrium because at this temperature because there is only one value of Kc.

[NO] = System 1 - System 2
1.06 1.56
[N2]
[O2]

Since the equilbrium constant does not have units it doesn't matter which unit we use for concentration when calculating Kc.

2a) At T1, K=0.013
At T2, K = 083

If 1.00 mole of A is placed in a 1.00L reaction vessel, at which temperature will the amount of B at equilbfrium be higher? Explain your answer.

2b) If delta H < 0, which temperature is higher? T1 or T2? Explain your answer.

3) Use the information below to calculate Kc for the follwing reactiosn at 600 decrees celcius

C02(g) + H2(g) <-> CO(g) + H2O(g)

A gas mixture that consits of equal amounts of Co and H20 was injected into a 1.97 rigid walled container at 600 degreees ceclius until the pressure reached 7.25 atm. When the reaction reaced equilbirum, 0.024 mole Of CO were present.

Thx much.

So...what have you tried so far?

1) To calculate Kc, we need to set up the equilibrium expression and plug in the given values for the concentrations of the reactants and products. In this case, the equilibrium expression is Kc = [N2][O2]/[NO]^2. Plugging in the concentrations from System 1, we get Kc = (1.06 x 1.06)/(1.56)^2 = 0.46. Similarly, for System 2, we get Kc = (1.56 x 1.56)/(1.06)^2 = 2.32. Since these two values of Kc are not equal, neither system is at equilibrium.

2a) To determine which temperature will result in a higher amount of B at equilibrium, we need to compare the values of Kc at T1 and T2. Since Kc is directly proportional to temperature, a higher value of Kc indicates a higher amount of B at equilibrium. Therefore, at T2, the amount of B at equilibrium will be higher.

2b) If delta H is negative, it means that the reaction is exothermic. In this case, at T2, the temperature is higher and therefore the reaction will favor the products, resulting in a higher amount of B at equilibrium.

3) To calculate Kc, we need to use the ideal gas law to convert the given pressure and number of moles into concentrations. The ideal gas law is PV = nRT, where P is pressure, V is volume, n is number of moles, R is the gas constant, and T is temperature. Rearranging this equation, we get n/V = P/RT. Plugging in the given values, we get n/V = 7.25/0.0821 x 873 = 0.0951. Since the gas mixture consists of equal amounts of CO and H2O, the concentration of CO is 0.0951/2 = 0.04755 and the concentration of H2O is also 0.04755. Plugging these values into the equilibrium expression Kc = [CO][H2O]/[CO2]

## 1. What is chemical equilibrium?

Chemical equilibrium is a state in a chemical reaction where the rate of the forward reaction is equal to the rate of the reverse reaction, resulting in no overall change in the amount of reactants and products.

## 2. How do you calculate Kc?

Kc, or the equilibrium constant, is calculated by taking the concentration of products raised to their respective stoichiometric coefficients and dividing it by the concentration of reactants raised to their respective stoichiometric coefficients. This is only applicable for reactions in a closed system at equilibrium.

## 3. What factors can affect the value of Kc?

The value of Kc can be affected by changes in temperature, pressure, and the initial concentrations of reactants and products. Changes in any of these factors can shift the equilibrium position and therefore change the value of Kc.

## 4. How can you use Kc to predict the direction of a reaction?

If Kc is greater than 1, it indicates that the products are favored at equilibrium and the reaction will proceed in the forward direction. If Kc is less than 1, it indicates that the reactants are favored at equilibrium and the reaction will proceed in the reverse direction. If Kc is equal to 1, it indicates that the reaction is at equilibrium.

## 5. Can Kc be used for all types of chemical reactions?

No, Kc is only applicable for reactions where the concentrations of reactants and products are measurable and the reaction is in a closed system at equilibrium. Reactions involving gases or ions in solution are usually more suitable for Kc calculations.

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