UNIT 4 𖦹⋆｡°✩ Flashcards
(30 cards)
what is chemical equilibrium
the phenomenon that occurs when the rate of the forward reaction equals the rate of the reverse reaction
what happens to the concentrations of all participants during chemical equilibrium
the concentrations in the reaction remain unchanged
what are the characteristics of a system in dynamic equilibrium
༻ there is some amount of every reactant and product present in the system
༻ the system is dynamic at the microscopic level
༻ the system is unchanging at the macroscopic level
༻ the system must be closed
what is equilibrium stress
a change in the environmental conditions of a system
what is Le Chatelier’s Principle
when an equilibrium system undergoes stress, it reacts to this stress in an attempt to minimize it
what factors affect a system at equilibrium
༻ concentration changes
༻ temperature changes
༻ pressure/volume changes
༻ catalysts
༻ addition of an inert gas
where does equilibrium lie if Keq is very large
the equilibrium lies far to the right since product concentrations must be greater than reactant concentrations (numerator > denominator)
where does equilibrium lie if Keq is very small
the equilibrium lies far to the left since reactant concentrations must be greater than product concentrations (numerator < denominator)
where does equilibrium lie if Keq = 1
equilibrium does not lie in any particular direction because the reactant concentrations must be very close to the product concentrations
what does changing the temperature do to the Keq of an endothermic reaction
increasing temperature causes equilibrium to shift to the right, so Keq increases as temperature increases and decreases as temperature decreases
what does changing the temperature do to the Keq of an exothermic reaction
increasing temperature causes the equilibrium to shift to the left, so Keq decreases as temperature increases and increases as temperature decreases
what is a heterogeneous system
one which involves a reaction between 2 or more states of matter
what is a homogeneous system
involves a reaction where all participants are present in the same state
what is the difference between saturated and unsaturated solution
an unsaturated solution will continue to dissolve solute, and a saturated solution can no longer dissolve solute particles
what does Ksp stand for
solubility product constant
what does it mean if Ksp is very large
equilibrium lies far to the right favouring the forward reaction and product formation
what does it mean if Ksp is very small
equilibrium lies far to the left favouring the reverse reaction and reactant formation
what is a salt
any ionic compound that does not contain H+, OH-, or O2-
what is molar solubility
the amount of solute dissolved in 1.0L of its saturated solution
why must ions be present in water
because water is a good conductor of electricity
what is the pH scale
a numerical scale from 0-14 used to measure acidity and alkalinity
what is an Arrhenius acid
any substance that reacts with water to increase the hydrogen ion concentration
what is an Arrhenius base
any substance that reacts with water to increase the hydroxide ion concentration
what are the characteristics of strong acids and bases
༻ no equilibrium present
༻ molecules are completely ionized
༻ ion concentration is extremely high
༻ Ka/b values are very high
