What is equilibrium?
A state of a system where no observable or measurable change occurs over time.
What is static equilibrium?
A state where a system is at rest and remains in a fixed position.
What is dynamic equilibrium?
A state in a reversible reaction where forward and backward reactions occur at equal rates.
What happens to concentrations at dynamic equilibrium?
Concentrations of reactants and products remain constant.
Give an example of a reversible reaction.
N₂O₄(g) ⇌ 2NO₂(g)
What type of system is required for equilibrium?
A closed system.
State Le Chatelier’s Principle.
If a system at equilibrium is disturbed, it adjusts to counteract the disturbance.
List three factors affecting equilibrium.
Temperature, concentration, and pressure.
How does increasing reactant concentration affect equilibrium?
Shifts equilibrium to the right (forward reaction).
How does increasing product concentration affect equilibrium?
Shifts equilibrium to the left (backward reaction).
How does increasing temperature affect an endothermic reaction?
It favors the forward reaction.
How does increasing temperature affect an exothermic reaction?
It favors the backward reaction.
How does increasing pressure affect gaseous equilibrium?
It favors the side with fewer moles of gas.
What is the effect of a catalyst on equilibrium position?
It does not change the position of equilibrium.
What does a catalyst do in equilibrium?
Speeds up both forward and backward reactions equally.
Write the Haber process equation.
N₂(g) + 3H₂(g) ⇌ 2NH₃(g)
Why does high pressure favor ammonia formation?
Because the reaction reduces gas moles from 4 to 2.
Why is a moderate temperature used in the Haber process?
To balance yield and reaction speed.
State the Law of Mass Action.
Reaction rate is proportional to the product of reactant concentrations raised to their coefficients.
Write the rate expression for aA + bB → products.
r = k[A]a[B]b
Write the general expression for Kc.
$$ K_c = \frac{[C]^c[D]^d}{[A]^a[B]^b} $$
Write the general expression for Kp.
$$ K_p = \frac{P_C^c \cdot P_D^d}{P_A^a \cdot P_B^b} $$
Are solids included in equilibrium constant expressions?
No, solids are excluded.
What does Kc > 1 indicate?
Products are favored at equilibrium.
What does Kc < 1 indicate?
Reactants are favored at equilibrium.
What does Kc = 1 indicate?
Neither reactants nor products are favored.
Does equilibrium depend on starting with reactants or products?
No, equilibrium can be reached from either side.
What is physical equilibrium?
Equilibrium during a reversible physical change.
What is chemical equilibrium?
Equilibrium during a reversible chemical reaction.
Why is equilibrium important in industry?
It helps determine optimal conditions for maximum yield and efficiency.
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