1.7- Simple Equilibria and Acid Base Reactions Flashcards
-What are reversible reactions?
where the reactants react to form products, which then react to reform the initial reactants
How is a reversible reaction shown in an equation?
double arrow
What does dynamic equilibrium mean?
the rate of the forward reactions equals the rate of the reverse reaction
concentrations at equilibrium?
reactants and products remain constant
When can dynamic equilibrium occur?
in closed systems where no substances can get in or out in order to influence the reactions
What is Le Chatelier’s principle?
when a system in dynamic equilibrium is subjected to a change
the position of equilibrium will shift to minimise the change
What is the position of equilibrium if the temperature increases?
it will shift to favour the endothermic route as the excess heat needs to be removed from the system to lessen the effect of the initial increase
therefore it will increase the yield of the products in the endothermic route
What is the position of equilibrium if the temperature decreases?
it will shift to favour the exothermic route as the heat needs to be gained
so the yield of the products in the exothermic route will increase
What is the position of equilibrium if pressure increases?
it will shift to favour the side with the least number of moles, to reduce the pressure
increasing the yield of the products on this side of the reaction
What is the position of equilibrium if pressure decreases?
it will shift to favour the side with the most number of moles, as the pressure has been lost
increasing the yield of the products on this side of the reaction
What is the position of equilibrium if concentration of the reactants increases?
it will shift to favour the forward reaction that produces the products as more molecules
increases the yield of products
What is the position of equilibrium if concentration of the products increases?
it will shift to favour the backward reaction that reforms the reactants
What affect does catalysts have to reactions?
no effect to the position of equilibrium as they increase the rate of the forward and backward reaction equally
they do allow equilibrium to be reached faster
What is equilibrium constant?
known as Kc
indicates the position of equilibrium in terms of concentration
What can change Kc for an equilibrium?
temperature
What is the equation for Kc?
(C)^c x (D)^d / (A)^a x (B)^b
What is Bronsted/Lowry theory?
Acids will act as donors of protons H+ (aq)
Bases will react in order to accept a proton H+ (aq)
What is water said to be in terms of acid and base?
amphoteric
as it can react as an acid and a base depending on conditions
What does dissociation mean?
refers to a reaction where a molecule or substance breaks apart into smaller units
What is ionisation?
refers to a reaction which forms ions from charged particles
What is pH?
-log[H^+(aq)]
What does H^+ refer to in pH equation?
concentration
What is a strong acid?
an acid that fully dissociates into ions
What is a weak acid?
an acid that only partially dissociates into ions
