gen chem chapter 6 mcat

reversible

reactions eventually reach a state in which energy is minimized and entropy in maximized

dynamic

• The rate of the forward reaction (reactants forming products) equals the rate of the reverse reaction (products forming reactants).

• The concentrations of reactants and products remain constant, even though the reactions are still occurring. 

law of mass action

gives the expression for the equilibrium constant (k eq) the reaction quotient Q has the same form but can be calculated by concentrations on reactants and products

Q

a calculated value that related the reactant and product concentrations at any given time during a reaction

Keq

the ratio of products to reactants and equilibrium, witch each species raised to its stoichiometric coefficient. Is constant at a constant temp

forward direction

Q<Keq G<0

dynamic equilibrium

Q=Keq G=0

reverse direction

Q>Keq G>0

more product

Keq >1

product equals reactants

Keq=1

more reactants

Keq<1

negligible amount of reactant

Keq ««<1

Le chatelier’s principle

states that when a chemical system experiences a stress it will react so as to restore equilibrium

kinetic products

higher in free energy, can form at lower temperatures. termed fast products because they can form quickly

thermodynamic products

lower in free energy, more stable. More spontaneous

right

increasing concentrations of reactants, lowering concentrations of products shifts a reactions to the —

left

increasing the concentrations of products or decreasing concentrations of reactants shifts a reaction to the —

fewer moles of gas

increasing the pressure on a gaseous system (decreasing its volume) will shift the reaction to the side that has —-

more moles of gas

Decreasing the pressure on a gaseous system (increasing its volume) will shift the reaction to the side that has —-

endothermic

heat is a reactant

exothermic

heat is a product