Unit 10- Equilibrium, Acids & Bases Flashcards
Many chemical reactions are _____
Reversible
Initially, only reactants are present and therefore the reaction proceeds only in the forward direction. As the product concentration builds up, however, the reverse reaction begins to occur. Equilibrium is established when the rates of the forward reaction and reverse reaction are _____. Chemical reactions are _____ processes. When equilibrium is reached, reactants are still being converted to products and products are converted to reactants, however the concentrations remain _____.
Equal-Dynamic-Constant
Describe everything about the equilibrium expression.
aA+bB—>cC+dD; K= [C]^c[D]^d/[A]^a[B]^b ; Products/Reactants; Concentrations are expressed in M (mol/liter) ; Only gases and solutions are included in the equilibrium expression- pure liquids and solids are not included as their concentration is constant.
If K>1, then
Product concentration is greater than reactant concentration and the equilibrium lies toward the product side.
If K<1, then
Reactant concentration is greater than product and equilibrium lies toward the reactant side.
During the use of Ice Charts, the sign of the change is determined by
If the initial concentration is 0, it will always be positive; also, the mole ratios are what determine the multiple of the change.
When you’re solving things in the equilibrium section, you must use the _____
Equilibrium Expression
Describe everything about the reaction quotient.
aA+bB—>cC+dD ; Q=[C]0^c[D]0^d/ [A]0^a[B]0^b
If Q>K , then
the product concentration is higher than it will be at equilibrium. Products will be consumed and reactants will be produced in order for equilibrium to be established (shift left).
If Q
the reactant concentration is higher than it will be at equilibrium. Reactants will be consumed and products will be produced in order for equilibrium to be established (shift right).
If Q=K, then
The system is at equilibrium.
When can the assumption rule be used?
You may use the assumption of []-x=[] when k is at least 100x smaller than [] or []eq is within 5% of []0; also, you must always check at the end to see if the answer is within 5% of the assumption used.
Define Le Chatalier’s Principle
The reaction will shift forward or backward in order to re-establish equilibrium. If a substance is added, it will always shift away from it.
In Le Chatalier’s Principle, when asked about heat, …
Figure out of the reaction is exothermic or endothermic; for instance, if it’s exothermic and you increase the temperature, the shift will be to the left.
