# CHEM126 – CHAPTER 14 – BASIC HOMEWORK / EQUILIBRIUM I

### Question 1 Help: Equilibrium expression

Select one: ### Explanation ### Question 2 Help: Equilibrium expression example

Select one: Look above!

### Question 3 Select one: f. –

### Explanation

Look above!

* Remember NOT to include liquids and/or solids in the expression.

### Question 4 Select one: ### Explanation

Look above!

Again tricky tricky no solids and/or liquids.

### Question 5 Select one: ### Explanation

YOU GOT THIS KIDDOS

### Question 6

Consider the reaction: 3A(g) + B(s) ↔ 5C(s) + 2D(g).
In a 5.00 L container the reactants and products are at equilibrium. There are 0.44 mol A, 0.30 mol B, 1.43 mol C, and 0.47 mol D. What is the equilibrium constant?

Help: Equilibrium constant ### Explanation

Hint, remember to first write the equilibrium expression and convert the moles to concentrations.

K = [D]^2 / [A]^3
K= [0.47/5]^2/ [0.44/5]^3
K=12.966

### Question 7

Consider the reaction: A(g) + 3B(s) ↔ 3C(g) + 2D(g).
In a 2.00 L container the reactants and products are at equilibrium. There are 0.47 mol A, 0.58 mol B, 1.84 mol C, and 0.27 mol D. What is the equilibrium constant? ### Explanation

Hint, remember to first write the equilibrium expression and convert the moles to concentrations.
K = [C]^3[D]^2 / [A]
K = [1.84/2]^3[0.27/2]^2 / [0.47/2]
K=0.06038974

### Question 8  ### Explanation

2-x =1.14

x=0.86

y=3x=2.58

x=z=0.86

3H2 = 4 – 3(0.86) = 1.42

2NH3 = 0 + 0.86 = 0.86

Kc = [0.86]^2/ [1.14][1.42]^3= 0.145

### Question 9

What is y, that is, how much hydrogen is used?

(Hint, use one of the methods used in the balance equation review problems to do the calculation. Enter amount as a positive quantity. An additional hint is given in the feedback.) ### Explanation

Additional hint: What is x? It is the amount of nitrogen used. What is the relationship between the amount of nitrogen used and the amount of hydrogen used?

### Question 10

What is the equilibrium number of moles of hydrogen? ### Question 11

What is z, that is, how much ammonia is produce? ### Question 12

What is the equilibrium constant, Keq?

(Remember to convert the number of moles to moles per liter or concentration in the equilibrium expression.) ### Question 13

What is the equilibrium expression for:

Ca(OH)2(s) ↔ Ca2+(aq) + 2OH(aq)?

Select one: ### Explanation

IF YOU’RE NOT A GAS YOU CANT SIT WITH US

### Question 14

Determine the equilibrium constant for the above reaction.

0.1 mol of Ca(OH)2 is placed in 2 L of water and stirred. At equilibrium, at a certain temperature, 0.0224 mol of Ca(OH)2 dissolves. What is Keq? (Assume, the volume of the solution is the same as the initial volume of water.) ### Explanation

After determining the mol of Ca2+ and the mol of OH, remember to convert them to concentrations.
Kc= [Ca^2+][OH-]^2
(0.0224/2)(2*0.0224/2)^2 = 5.6e6

### Question 15

Consider the reaction: 3A(g) + B(s) ↔ 5C(s) + 2D(g) Keq = 0.42 M-1.
[A] = 0.73 M and [D] =0.22 M. Some B and C are present. What is Q?

Help: Q and Keq ### Explanation ### Question 16

For the above value of Q
Select one: ### Question 17

Consider the reaction: 3A(g) + B(s) ↔ 5C(s) + 2D(g) Keq = 0.42 M-1

Same reaction and Keq, but this time:
[A] = 0.94 M and [D] =0.95 M. Some B and C are present. What is Q? ### Explanation

Q= [0.95]^2/[0.94]^3=1.09

### Question 18

For the above value of Q

Select one: ### Explanation

Q is large than Keq  so to obtain equilibrium the reaction must move to the left so there is more reactant and less product.