Consider the reaction: NH 4 HS(s) ⇌ NH 3 (g) + H 2 S(g) At a certain temperature, K c = 8.5⨉10 -3 . A reaction mixture at this temperature containing solid NH 4 HS has [NH 3 ] = 0.166 M and [H 2 S] = 0.166 M. Will more of the solid form or will some of the existing solid decompose as equilibrium is reached?

Hello everyone. So in this video we're gonna go ahead and take a look at this equation over here and we're just seeing if more of the CCO three will form or will some of the existing C C 03 to compose as equilibrium is reached in this reaction. So some things we need to go ahead and take a look at is first of all we need of course calculate for Q. If Q is equal to K value, then the reaction is at equilibrium. If our Q value is less than r K value, then the reaction shifts to the forward direction. And as you have guessed if Q is greater than R K value, then the reaction will shift in the reverse direction to reach equilibrium. Alright, so to go ahead and calculate for a Q value that's going to equal to the concentration of carbon dioxide. So these brackets just indicates the concentration value. And let's see here the Q value Is going to equal two or 0.215. And why is that? It's because we see that the concentration of CO2 is going to be given to us right there. That's why I wrote this here. So Because this 0.215 value is greater than our constant value which is listed right over here. So let's go ahead and actually highlight these to the problem. So we see that obviously 0.215 is greater than 0.0132 in the case. This just means that the reaction will go ahead and shift to the reverse direction to go ahead and try to reach equilibrium. So formally. Our answer then, is that if the equilibrium will ship in the reverse direction, then more solids will form. So our answer is that more CAC 03 four, And this is going to be my final answer for this problem. Thank you all so much for watching.

Ch.16 - Chemical Equilibrium

Tro - Chemistry: A Molecular Approach 5th Edition

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Ch.16 - Chemical Equilibrium

Problem 47

Chapter 16, Problem 47

Consider the reaction: NH₄HS(s) ⇌ NH₃(g) + H₂S(g) At a certain temperature, K_c = 8.5⨉10^-3. A reaction mixture at this temperature containing solid NH₄HS has [NH₃] = 0.166 M and [H₂S] = 0.166 M. Will more of the solid form or will some of the existing solid decompose as equilibrium is reached?

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Identify the reaction and the equilibrium constant expression: NH4HS(s) ⇌ NH3(g) + H2S(g). The equilibrium constant expression is K_c = [NH3][H2S].

Substitute the given concentrations into the equilibrium expression: K_c = (0.166)(0.166).

Calculate the reaction quotient, Q, using the initial concentrations: Q = [NH3][H2S] = (0.166)(0.166).

Compare the calculated Q with the given K_c value (8.5 \times 10^{-3}).

Determine the direction of the reaction: If Q < K_c, the reaction will proceed to the right, decomposing more solid NH4HS. If Q > K_c, the reaction will proceed to the left, forming more solid NH4HS.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Chemical Equilibrium

Chemical equilibrium occurs when the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products. In this state, the system is dynamic, meaning that reactions continue to occur, but there is no net change in the concentrations. Understanding equilibrium is crucial for predicting how changes in concentration, pressure, or temperature will affect the position of the equilibrium.

Equilibrium Constant (Kc)

The equilibrium constant (Kc) is a numerical value that expresses the ratio of the concentrations of products to reactants at equilibrium, each raised to the power of their coefficients in the balanced equation. For the reaction NH4HS(s) ⇌ NH3(g) + H2S(g), Kc = [NH3][H2S] / [NH4HS]. A small Kc value, like 8.5 * 10^-3, indicates that at equilibrium, the concentration of products is much lower than that of reactants, suggesting that the reaction favors the formation of reactants.

Le Chatelier's Principle

Le Chatelier's Principle states that if a system at equilibrium is subjected to a change in concentration, temperature, or pressure, the system will adjust to counteract that change and restore a new equilibrium. In the context of the given reaction, if the concentration of NH3 and H2S is increased, the system will shift to favor the formation of NH4HS, leading to the decomposition of some solid NH4HS to reach equilibrium.

Consider the reaction: NH4HS(s) ⇌ NH3(g) + H2S(g) At a certain temperature, Kc = 8.5⨉10-3. A reaction mixture at this temperature containing solid NH4HS has [NH3] = 0.166 M and [H2S] = 0.166 M. Will more of the solid form or will some of the existing solid decompose as equilibrium is reached?

Verified video answer for a similar problem:

Key Concepts

Chemical Equilibrium

Equilibrium Constant (Kc)

Le Chatelier's Principle