Chem Lesson 3: 13.1 - 13.4 Flashcards
Equilibrium
(Dynamic Equilibrium)
The forward and reverse reaction rates are equal and when the concentrations of reactants and products aren’t changing anymore but it doesn’t necessarily mean that they are equal.
-The reversible reaction is still happening.
Reversible Reaction (Half forward arrow over half reverse arrow)
The reactants combine to form products and at the same time products convert into reactants.
-Forward reaction is happening at the same time as reverse reaction.
Reaction Rate
Speed at which a reaction takes place
Rate constant
Constant in the rate law that depends on the specific reactants on hand and is related to the activation energy and temperature.
Equilibrium Constant - Uppercase (K) (Definition)
The ratio of units (pressure or concentration) of the products over the reactants.
-Used to figure out whether we have more products or reactants.
Activity
How many particles appear to be present in a solution.
-Solids and Liquids have an activity of 1 and aren’t used in the equilibrium constants.
K,c Equilibrium Concentration Constant
Ratio of unit concentration of products over reactants.
-Let’s us see if we have more reactants or products in reversible reaction at equilibrium.
K,p Equilibrium Constant
Ratio of unit pressure of products over reactants.
-Let’s us see if we have more reactants or products.
-Ratio surrounded by brackets and starts with p
-K,p = (PCO)^2/(PO,2)
Pressure
Force exerted by gaseous molecules as they collide with the walls of their container.
K,eq
Another meaning for equilibrium constant. May or may not specify p or c.
K (equilibrium constant)»1
More products than reactants if the number is a lot bigger than one.
K (equilibrium constant)«1
A lot more reactants than products at equilibrium if the number is way less than one.
K (equilibrium constant) is close to 1
Similar ratio of reactants and products at equilibrium if the equilibrium constant is close to one.
Reaction Quotient (Q,c or Q,p)
Ratio of units (concentration or pressure) of products over reactants at any given time. (Equilibrium Constant is only at equilibrium).
-Used to determine whether we have more products or reactants in reversible reaction.
K,p Gasses or Aqueous Species?
Only Gasses
K,c Gasses or Aqueous Species?
Both
Homogenous Equilibria
All reactants and products in a reverse equilibrium reaction have the same phase. (Gas, Aqueous, etc)
Q > K (Which direction does reaction proceed)
Left
Q < K (Which direction does reaction proceed)
Right
Q = K (Which direction does reaction proceed)
Rxn at Equilibrium
Total Pressure
The sum of the partial pressures
Total Pressure (Units)
Pa, Kpa, atm, or torrents (look at the question)
Partial Pressure
Pressure of one type of gas in the total pressure.
Ideal Gas Law (Equation)
& what does n and R stand for.
PV = nRT
n= amount of Moles
R = Energy Constant (0.08206 L atm/m*K)
Partial Pressure - Mole Fraction (equation)
(mol of individual pressure)/Total Moles
Partial Pressure (Def)
Pressure of one specific gas molecule that’s apart of total pressure
Partial Pressure (Final step after mole fraction step)
Mole fraction * total pressure (usually given)
How to calculate partial pressure? (Two Steps) (Given Moles)
- Find mole fraction
- Multiple mole fraction by total pressure (not the total moles)
How to calculate partial Pressure (not given moles)
Ideal Gas Law:PV =nRT
R (Gas Law value)
0.0821 L*atm/mol * k
K,p K,c Relationship Equation
K,p = K,c(RT)^delta n
Delta^n (k,p k,c conversion equation
Sum[coefficients of products] - Sum[Coefficients of reactants]
-Must balance equation first
Le Chartilier’s Principle
When a chemical system at equilibrium is disturbed it returns to equilibrium by counteracting the disturbance.
Q < K (Le Charts - need to create more what?)
Products
Q > K (Le Charts - need to create more what?)
Reactants
Stress
Anything that takes the system out of equilibrium.
Increase in Pressure (Le Chart - What direction does the reaction move?)
Side with the less moles.
Decrease in Pressure (Le Chart - What direction does the reaction move?)
Move to the side with more moles.
Le Chart - Does temp affect Q (Concentrations) or Kc (equilibrium constant)?
Both
Le-Chart - Increasing heat in an endothermic reaction causes what shift?
To the right
Le-Chart - Increasing heat in an exothermic reaction at equilibrium causes what shift?
Shift to the left.
Endothermic Reaction
Energy is taken in. (Causes the temperature of the reaction mixture (system) to decrease).
Exothermic Reaction
Energy is given off. (Causes the temperature of the system (reaction mixture) to increase).
Does equilibrium happen in open or closed environments?
Closed
Shift to the left (What do reactants and products do?)
Reactants increase and products decrease
Shift to the right (What do reactants and products do?)
Reactants decrease and the products increase.
Heat
Energy transferred to the motion of atoms or molecules.
Enthalpy (def)
State function that shows heat loss or gain in a system.
