Tensai Science Academy

Chemical equilibrium is reached when what occurs?

Forward and reverse reactions occur at equal rates
All reactions stop
Only products remain
Only reactants remain

At equilibrium, the concentrations of reactants and products are what?

Shifts equilibrium toward products
Shifts equilibrium toward reactants
Has no effect
Stops the reaction

The equilibrium constant is represented by which symbol?

Shifts equilibrium to increase products
Shifts equilibrium to increase reactants
No shift occurs
Reaction stops

If Kc is much greater than 1, what does this indicate?

Increases pressure, favors fewer gas molecules
Increases pressure, favors more gas molecules
No effect on gases
Decreases reaction rate only

What effect does increasing temperature have on an exothermic equilibrium reaction?

Shifts equilibrium to absorb heat (endothermic direction)
Shifts equilibrium to release heat
No change
Reaction stops

Which factor does not affect the value of the equilibrium constant?

Catalyst speeds up rate, but equilibrium position unchanged
Catalyst shifts equilibrium to products
Catalyst shifts equilibrium to reactants
Catalyst removes equilibrium

Which factor changes both the rate of forward and reverse reactions equally?

Kc = [products]/[reactants]
Kc = [reactants]/[products]
Kc = 1/[products]

In the Haber process, what catalyst is used?

Large Kc means products favored
Large Kc means reactants favored
Kc unrelated to position
Kc = 0 always

What happens to equilibrium when pressure is increased for a reaction involving gases?

Small Kc means reactants favored
Small Kc means products favored
Kc has no meaning
Kc is negative

Which equilibrium expression corresponds to the reaction: N? + 3H? ? 2NH??

No, pure solids/liquids are excluded
Yes, always included
Sometimes, depending on reaction
Only liquids excluded

A reaction quotient (Q) is used to predict what about a system?

Only aqueous and gases are included
Only solids included
All states included
Only liquids included

When Q < K, the reaction shifts in which direction?

Yes, concentrations are raised to power of stoichiometric coefficients
No, coefficients ignored
Only reactants squared
Only products squared

When Q > K, the reaction shifts in which direction?

Reaction quotient (Q)
Activation energy
Entropy
Heat capacity

What is the unit of equilibrium constant Kc for gaseous reactions?

Q < Kc: forward reaction favored
Q > Kc: forward reaction favored
Q = Kc: forward favored
Q < Kc: equilibrium reached

A dynamic equilibrium means what at the molecular level?

Q > Kc: reverse reaction favored
Q < Kc: reverse favored
Q = Kc: reverse favored
Q > Kc: equilibrium reached

Which principle is applied in industrial processes to maximize yield?

Q = Kc: system is at equilibrium
Q = Kc: products favored
Q = Kc: reactants favored
Q = Kc: no reaction possible

The addition of an inert gas at constant volume has what effect on equilibrium?

Temperature
Pressure
Concentration
Catalyst presence

At equilibrium, the forward and reverse rates are what?

Adding catalyst speeds up equilibrium but does not shift it
Catalyst shifts equilibrium toward products
Catalyst shifts equilibrium toward reactants
Catalyst removes equilibrium

The equilibrium constant for a reaction depends on what factor?

Changes equilibrium position and Kc
Changes equilibrium position only
Changes Kc only
Has no effect at all

Tensai Science Quiz

Chemical Equilibrium