Equilibrium Review (Set 2)

Gaseous hydrogen bromide decomposes at elevated temperatures according to the following equation:

2HBr (g) ⇄ H₂ (g) + Br₂(g)

At a certain temperature a 2.00 L flask is initially filled only with 0.600 mol of HBr. What is the value of K_c at that temperature if the flask contains 0.104 mol of H₂ at equilibrium?

• 7.04 x 10^-2

• 4.40 x 10^-2

• 0.210

• 3.00 x 10^-2

K_p is equal to 48.70 at 731 K for the reaction: H₂ (g) + I₂(g) ⇄ 2HI(g)

Initially the mixture contains 0.08592 atm each of H₂ and I₂ and 1.0000 atm of HI. What is the pressure (in atom) of HI at equilibrium?

• 0.9108 atm

• 0.9140 atm

• 0.7955 atm

• 0.9498 atm

The pictures represent the equilibrium state for four different reactions with the same generic equation A₂ + X₂ ⇄ 2AX (Where X is either B, C, D, or E). [NOTE: "X" atoms are shaded and A atoms are unshaded.] Which reaction has the SMALLEST equilibrium constant?

• A₂ + B₂ ⇄ 2AB

• A₂ + C₂ ⇄ 2AC

• A₂ + D₂ ⇄ 2AD

• A₂ + E₂ ⇄ 2AE

Tags

NGSS.HS-PS1-7

For the equilibrium reaction

2NH₃(g) + 22 kJ ⇄ N₂(g) + 3H₂(g),

which of the following changes would result in the formation of more N₂ and H₂ at equilibrium?

• increasing pressure

• increasing temperature

• adding N₂

• removing NH₃

Tags

NGSS.HS-PS1-6

Q4. A mixture initially containing 0.392 M A(g) and 0.452 M B(g) is allowed to come to equilibrium at 300 K. The reaction is as follows: 3 A(g) + 2 B(g) ⇄ C(g) + D(g)

At equilibrium, [C] = 0.00128 M. What is the value of K_c?

• 1.39 x 10^-4

• 7.35 x 10^-3

• 7.19 × 10⁶

• 1.36 × 10²

What is the equilibrium-constant expression for

CO₂(g) + H₂(g) ⇄ CO(g) + H₂O(l)

• K_c= [CO][H₂O]/[CO₂][H₂]

• K_c= [CO₂][H₂]/[CO]

• K_c= [CO₂][H₂]/[CO][H₂O]

• K_c= [CO]/[CO₂][H₂]

When the system X + 2 Y ⇄ Z has reached equilibrium, which of the following is TRUE?

• The forward reaction and backward reaction stop.

• The forward reaction has sped up and backward reaction has slowed down.

• The forward and backward reactions occur at the same rate.

• The forward reaction has slowed down and backward reaction has sped up.

Why is equilibrium called a dynamic state?

• Chemists try to convert as much reactants as possible into products.
• The reactions at equilibrium continue to take place once equilibrium is established.
• The products of a forward reaction are favored, so equilibrium lies to the right.
• All chemical reactions are considered to be reversible under suitable conditions.

Tags

NGSS.HS-PS1-6

What kind of equilibrium does the reaction below show?
CaCO_{3 (s)} ⇌  CaO _(s) + CO_{2 (g)}

• Heterogeneous equilibrium, all the reactants and products are in the same physical state.
• Homogeneous equilibrium, all the reactants and products are in the same physical state.
• Heterogeneous equilibrium, the reactants and products are present in more than one physical state
• Homogeneous equilibrium, the reactants and products are present in more than one physical state

Q21. Determine the value of K for the reaction:

2 N₂(g) + O₂(g) ⇄ 2 N₂O(g)

Equilibrium concentrations are:

[N₂] = 3.6 M, [O₂] = 4.1 M,

[N₂O] = 3.3 × 10^-18 M

• 2.0 × 10^-37

• 4.5 × 10¹⁸

• 5.0 × 10³⁶

• 2.2 × 10^-19