Equilibrium review

Define chemical equilibrium.

• A reaction is reversible.
• The concentration of the reactants is equal to the concentration of the products.
• The rate of a forward reaction is equal to the rate of the reverse reaction.
• The reaction stops and no further change in concentration occurs.

Which of the two graphs shows a reaction / reactions that reach equilibrium?

• The left one.
• The right one.
• Both of them.
• Neither.

For the reaction...
N₂  +  O₂  ⇌  2NO:  Δ H = +182 kJ mol^-1.
If the temperature is increased the equilibrium position will shift _______.

• to the left
• to the right
• to the left and right
• neither left nor right

What was the equation for this reaction? All the substances were gases.

• A + B ⇌ 2C
• 2A + B ⇌ 2C
• 2C ⇌ 2A + B
• A2 + B ⇌ C2

For the reaction...
H₂ (g) + Cl₂ (g) ⇌  2HCl (g)  +ΔH
If the pressure in the system is increased, the value of Kc will _______.

• decrease
• increase
• not shift at all (2 mol of gas each side)
• stay the same

2SO₂(g)+ O₂(g) ⇌ 2SO₃(g)
Decreasing volume of container (increasing the pressure)will

• shift equilibrium to the right
• shift equilibrium to the left
• change the value of Kc
• have no change on equikliibrium position

N₂O₄(g) ⇌ 2NO₂(g)
What is the concentration equilibrium constant expression?

• K_c = [NO₂]² / [N₂O₄]
• K_c = [N₂O₄] /[ NO₂]²
• K_c = [N₂O₄]² / [NO₂]
• K_c = [N₂O₄] x [NO₂]²

Tags

NGSS.HS-PS1-7

 A + B ⇌ C -ΔH
If heat energy is then removed (it is cooled), the equilibrium will shift

• toward the middle
• toward the reactant side
• toward the product side

Le Chatelier's Principle states that if a chemical system at equilibrium is stressed (a change is made)

• the system will adjust to increase the stress / imposed change
• the system will adjust to reduce the stress / imposed change
• the system will not adjust

 CH₄(g) + 2O₂(g) ⇌ CO₂(g) + 2H₂O(g)   ΔH = + 30 kJ
If some CH₄ is removed, which reaction is favoured?

• Right
• Left
• Reverse 
• Forward