Which of the following equilibrium expressions for the dissolution of calcium fluoride (CaF2 ) in water is correct?
Ksp = [Ca2+ ] [ F − ]^2
When 1 mg of solid AgCl is dissolved in water, the following equilibrium is established with an equilibrium constant value of K1:
AgCl(s) <==> Ag+(aq) + Cl-(aq)
After equilibrium is established, an additional 9g of AgCl is added to the mixture. The equilibrium position shifts, and a new equilibrium is established with a equilibrium constant value of K2. How are K1 and K2 related?
K1 is equal to K2
C(s) + CO2(g) <==> 2CO(g)
When this system is at equilibrium at 700 degrees C in a 1 L container, there are 0.2 mol CO, 0.4 mol CO2, and 0.8 mol C. When the system is cooled to 600 degrees C, an additional 0.04 mol C forms. Calculate the equilibrium constant at 700 degrees C and again at 600 degrees C.
Kc = 0.1 at 700 °C and Kc = 0.033 at 600 °C
For the reaction
C(s) + CO2(g) <==> 2CO(g), Kp = 3.7. If the final total pressure is 2.78 atm, Which of the following shows the correct quadratic equation to solve for the change in partial pressure?
x ^2 + 3.7x − 10.3 = 0
For the reaction N2O4(g) <==> 2NO2(g), Kp = 2.9 If the total pressure at equilibrium is 1.63 atm, what are the final partial pressure for the system at equilibrium?
1.16 atm (for NO2 ); 0.47 atm (for N2O4 )
If the value of the equilibrium constant with regard to pressure (Kp ) is found to be 1.5 at 15°C, what is the value of the equilibrium constant with regard to concentration?
N2 + 2O2(g) <==> N2O4(g)
(R = 0.0821 L • atm / (mol • K))
8.4 × 10^2
Which of the following factors will NOT disrupt a system at equilibrium?
leaving the reaction untouched for an infinite period of time
For a reaction A+B -> AB, the value of the equilibrium constant is less than 1. Therefore, which of the following statements is correct?
Equilibrium lies toward the formation of the reactants.
The ideal gas equation can be written as _______________
P = (n / V)RT
In the ideal gas equation, the volume, V, ____________________
varies inversely with pressure
Which statement best describes how the equilibrium constant and the reaction quotient can help a chemist?
They help a chemist evaluate in which direction a reaction will proceed in order to achieve equilibrium
Look at the reaction of hydrogen and iodine to form HI gas.
H2(g) + I2(g) <==> 2HI(g)
Q is the reaction quotient. The value for Q at any point in this reaction is equal to [HI]2 / [H2 ] [ I2 ]. Which statement about Q is not correct?
The values for Q and Keq for the reaction are constant.
Look at the following system.
PCl5(g) <==> PCl3(g) + Cl2(g)
Suppose that the equilibrium constant, KP, is 490 (at 340°C). If the partial pressure of PCl3 is 1.87 atm and the partial pressure of Cl2 is 0.29 atm, what is the partial pressure of PCl5?
0.0011 atm
Look at the following equilibrium reaction of three gases.
N2(g) + 3H2(g) <==> 2NH3(g)
What would happen to the value of Q in this system if the volume was changed from 3 L to 9 L. If the system was at equilibrium at 3 L, in which direction would the reaction proceed to reach equilibrium at 9 L.
The new value for Q would be nine times the original value for Q. Therefore, the reverse reaction would occur in order to reach a new equilibrium.
Which of the following statements about a catalyst is correct?
A catalyst affects the rate of reaction
If the value of the equilibrium constant with regard to concentration (Kc ) is found to be 2.54 × 106 at 30°C, what is the value of the equilibrium constant with regard to pressure?
(R = 0.0821 L • atm / mol • K)
PCl3(g) + Cl2(g) <==> PCl5(g)
1.02 × 10^5
What is the best definition of the reaction quotient, Q?
The reaction quotient is a measure of where a reaction “is at” at a given moment.
Suppose that you have 38 L of components in a flask (at 400 degrees C). The components include 2.7 mol N2, 0.28 mol H2, and 1.3 mol NH3. If the equilibrium equation is N2(g) + 3H2(g) <==> 2NH3(g) (where Keq = 0.50 at 400 degrees C), which of the following shows the correct expression for the reaction quotient and the correct concentration values for each gas?
Q = [ NH3 ]2 / [ N2 ] [H2 ]^3; [ NH3 ] = 0.034 mol / L; [ N2 ] = 0.071 mol / L; [H2 ] = 0.007 mol / L
In the following reaction, CH4(g) + H2O(g) <==> CO(g) + 3H2(g) (where Kp = 1.8*10^-7 (at 600K)), assume that, initially , there is no methane. Assume also that you have large amounts of the two products. Which statement summarizes the predicted movement of the reaction as it shifts toward equilibrium?
The reaction will move to the left because there initially is no methane
Why is it true that an equilibrium does not depend on where you start the reaction?
The substances will want to assume their most stable arrangement. This is achieved by the system moving to equilibrium.
Look at the following ICE diagram problem. Which gas is the limiting reagent? CH4(g) + H2O(g) <==> CO(g) + 3H2(g)
CO
H2(g) + I2(g) <==> 2HI(g) Kp = 92,.6 for this reaction. Suppose that you start with PH2 = 0.207 atm, PI2 = 0.191 atm, and PHI = 2.32 atm. You add H2 until its concentration reaches 0.299 atm. Let x equal the change in partial pressure of H2. What is the correct quadratic equation when solving for x in this reaction?
88.6x^2 - 54.7x - 0.10 = 0
Suppose that you have a flask containing CH3 at a partial pressure of 2.3, H2O at a partial pressure of 1.5, CO at a partial pressure of 2.8, and H2 at a partial pressure of 0.3. What is the reaction quotient for this reaction? CH4(g) + H2O(g) <==> CO(g) + 3H2(g)
0.022
Is the following statement true or false?
At high temperatures, enthalpy is a key component that determines where chemical equilibrium lies.
false
The term dynamic equilibrium means___________
that reactants and products are continuously interconverting, though their concentration remains the same.