Chapter Three: Equilibrium 1

Question 1

Physical Equilibrium

Answer 1

Does not involve changes to the chemical properties of the substance. Requires a closed system at a constant temperature.

Question 2

Chemical Equilibrium

Answer 2

Changes in the chemical composition of substances. Involves bond breaking and formation.

• Requires a closed system at a constant temperature.
• rate of forward reaction = rate of reverse

Question 3

Steady State vs Equilibrium

Answer 3

• A steady state system is an open system with an equal amount of materials entering and exiting the system
• Equilibrium is a closed system with no outside matter or energy

Question 4

How does a reversible reaction reach equilibrium? (3)

Answer 4

1. Closed system
2. Observable properties constant
3. Continual microscopic change between reactants and products
4. Rate of forward reaction = rate of reverse

Question 5

Keq

Answer 5

• equilibrium constant
• exponents in the expression are the same as the coefficients in the balanced chemical equation
• relates the concentration of products to reactants at equilibrium

Question 6

Homogeneous Equilibrium

Answer 6

All reactants and products are in the same physical state.

Question 7

Heterogeneous Equilibrium

Answer 7

Reactants and products are in different physical states.

Question 8

Le Chatelier’s Principle

Answer 8

If a system at equilibrium is subjected to an external stress, the equilibrium will shift to minimize the stress.

Question 9

Factors Affecting Equilibrium: Concentration

Answer 9

An increase in concentration will cause the reaction to shift towards the opposite side. Keq does not change.

Question 10

YOU CAN DO IT!!!!!!!

Answer 10

Seriously. Just a few more cards.

Question 11

Factors Affecting Equilibrium: Pressure

Answer 11

• Changing pressure only affects a reaction. with gases present.
• Increasing pressure will cause the side will the fewest moles to be favoured.
• does not change Keq

Question 12

Factors Affecting Equilibrium: Temperature

Answer 12

• An increase in temperature will favour the reaction that absorbs heat (endothermic: heat as a reactant)
• A decrease in temperature will favour the reaction that releases heat (exothermic: heat as a product)

Question 13

How does temperature change Keq?

Answer 13

• An entire side is favoured over the other, which alters the values
• if the forward reaction is favoured, more products and fewer reactants are produced, so Keq increases

Question 14

Factors Affecting Equilibrium: Catalysts

Answer 14

• Adding a catalyst will not change equilibrium, since it speeds up both the forward and reverse reaction. One side is not favoured over another
• just helps system reach equilibrium sooner