Chapter 7 - Chemical Equilibrium Flashcards
what is atmospheric carbon dioxide?
a greenhouse gas
what does atmospheric carbon dioxide contribute to?
climate change
how is carbon dioxide gas released to the atmosphere?
through combustion of fossil fuels
an example of a reversible reaction involving carbon dioxide gas
carbon dioxide gas dissolves in water to produce carbonic acid H2CO3 (aq), this is reversible, carbonic acid decomposes to produce water and carbon dixoide gas
what happens when concentrations of reactants and products are stable?
there is a balance in the rates of the forward and reverse reactions
is carbon dioxide gas in the atmosphere stable and what does this cause?
no, the formation of carbonic acid increases
what does the increase of carbonic acid in oceans cause?
acidification, and has an impact on shells composed of calcium carbonate (CaCO3 (s)), which dissolves in acidic solutions, can lead to bleaching of coral reefs
what does it mean when a chemical reaction proceeds to completion
one of the reactants runs out
define chemical equilibrium
the state of a reaction in which all reactants and products have reached constant concentrations in a closed system
define dynamic equilibrium
a balance between forward and reverse reactions that are occurring stimultaneously (rates of forward and reverse reactions are equal)
what are all chemical equilibriums?
dynamic equilibriums
what happens to reversible reactions in a closed system?
reach chemical equilibrium
what does it mean when molar ratio is the same?
concentrations are the same
what does a vertical line mean for reaction progress?
equilibrium
define equilibrium position
the relative concentrations of reactants and products in a system in dynamic equilibrium
by convention, how is equilibrium position communicated in reference to?
the left hand side (reactant side) or the right hand side (the product side)
what does it mean when equilibrium position is to the far right?
almost all reactants are converted to products, but the concentrations of reactants never reach zero
define reversible reactions
a chemical reaction that proceeds in both the forward and reverse directions, setting up an equilibrium in a closed system
at dynamic equilibrium, what is the concentration of reactants?
constant
how are reversible reactions indicated?
⇌
generalization for forward and reverse reactions regarding a closed chemical equilibrium system in constant environmental conditions
the same equilibrium concentrations are reached regardless of the direction by which equilibrium is reached
when is an ICE table useful?
for chemical equilibrium systems composed of aqueous solutions or gases
define equilibrium law
the mathematical description of a chemical system at equilibrium (reversible reaction)
define equilibrium constant
the numerical value defining the equilibrium law for a given system, units are not included when giving the value of K
what is the symbol for the equilibrium constant?
K
what does not change the K value?
the initial concentrations
what change the value of K?
temperature
what does equilibrium position describe?
the relative concentrations of reactants and products in a chemical reaction system
what can the magnitude of the equilibrium constant help you find?
the equilibrium position of a chemical reaction system
if K equals the forward reaction and K’ equals the reverse reaction, how are they related
they are reciprocals, 1/k’ = k
define homogeneous equilibrium
a chemical equilibrium in which all reactants and products are in the same state of matter
define heterogeneous equilbrium
a chemical equilibrium in which the reactants and products are present in at least 2 different states
what does the equilibrium position not depend on?
pure solids or liquids concentrations are not included in the chemical law equation because they do not affect the equilibrium position
why do pure solids/liquids not affect the equilibrium position?
their concentrations cannot change, they are constants
when the equilibrium constant is much greater than 1, what 3 things does this tell us?
the equilibrium position is far to the right, it favours the products, concentration of products are greater than the concentrations of the reactants
when the equilibrium constant is close to being equal to 1, what 3 things does this tell us?
equilibrium concentration of the products is similar to that of the reactants
when the equilibrium constant is much less than 1, what 3 things does this tell us?
equilibrium position is far to the left, favours reactants, concentration of reactants is greater than those of the products
how can chemical systems at equilibrium be disturbed?
through changes in temperature, pressure, concentration or a combination of these
what was the goal behind Le Chatelier’s investigations?
to maximize the yield of products from equilibrium systems
Le Chatelier’s Principle
when a chemical system at equilibrium is disturbed by a change in a property, the system adjusts in a way that opposes the change
what does le chatelier’s principle allow chemists to do?
predict qualitative effects of changes in concentration, pressure, and temperature on a chemical reaction system at equilibrium
define equilibrium shift
a change in concentration of reactants and products in order to restore an equilibrium state
what happens when you increase the concentration of a reactant to the equilibrium
equilibrium shifts to the right
when a reaction occurs, what happens to the concentration of reactants and products
concentration of reactants decrease while concentration of products increase