equilibrium

Question 1

what is a closed system?

Answer 1

a chemical system that is separated from its surroundings by a definite boundary so that no matter can enter or leave, but energy can enter or leave

Question 2

what is equilibrium and the three types?

Answer 2

chemical system with constant macroscopic properties (no observable change), phase, solubility, and chemical reaction.

Question 3

what is phase equilibrium

Answer 3

involves a single chemical substance existing in more than one phase in a closed system.

Question 4

what is solubility equilibrium?

Answer 4

involves a single chemical solute interacting with a solvent substance, where excess solute is in contact with the saturated solution.

Question 5

what is chemical reaction equilibrium?

Answer 5

involves the reactants and the products of a chemical reaction

Question 6

what is dynamic equilibrium?

Answer 6

• a balance between two opposite processes occurring at the same rate

Question 7

what is a forward reaction?

Answer 7

left-to-right change in an equilibrium

Question 8

what is a reverse reaction?

Answer 8

right-to-left change in an equilibrium

Question 9

what is the equilibrium constant?+ formula

Answer 9

• mathematical relationship that provides a constant value for a chemical system over a range of amount concentrations
  -Kc

Question 10

what is the equilibrium law?

Answer 10

• Kc = {[C]c[D]d}/{[A]a[B]b}
• ABCD represent chemical entity formulas
  -abcd represent coefficients in balanced equation
  (for reaction) aA + bB <> cC + dD

Question 11

rules and guidelines of an equilibrium constant value? (6)

Answer 11

• depends on system temperature
• independent of: reagent concentrations, catalyst present, time to reach equilibrium
• stated as numerical value, no units
• greater the more the system favours the formation of products

Question 12

what is le chatelier’s principle? (definition)

Answer 12

when a chemical system at equilibrium is disturbed by a change in property of the system, the system always appears to react in the direction that opposes change, until a new equilibrium is reached.
three stages: initial equilibrium, shifting non-equilibrium, and new equilibrium

Question 13

what is an equilibrium shift?

Answer 13

• change in concentration that occurs when an equilibrium is disrupted

Question 14

le chatelier’s principle: concentration

Answer 14

increase: shift to consume added reactant/product
decrease: shift to replace removed reactant/product

Question 15

le chatelier’s principle: temperature

Answer 15

increase: shift to absorb added heat energy
decrease: shift to replace removed heat energy

Question 16

le chatelier’s principle: volume

Answer 16

(gaseous systems only)
increase: decrease pressure, shift toward side with larger total chemical amount of gaseous entities
decrease: increase pressure, shift toward side with smaller total chemical amount of gaseous entities